January 04, 2015

Integrated Approach Navigation (IAN) - Review and Procedures

January 04, 2015/ Flaps 2 Approach

Japanese airlines nearly always gravitate to new technology. ANA landing RJAA (Narita, Japan)

Increased navigational accuracy obtained from software and hardware improvements have led to several enhanced approach types being developed for the Boeing 737. These augmented approach types provide a constant rate of descent, follow an approximate 3 degree glide path, and eliminate the traditional step-down style of approach.

This improves landing capability in adverse weather conditions, in areas of difficult terrain, and on existing difficult to fly approach paths. Not to mention, the benefits that a stabilized and safer approach bring: greater passenger comfort, less engine wear and tear, and lower fuel usage while bringing less workload for the flight crew.

In this article, I will discuss the concept of Integrated Approach Navigation (IAN) and explain the procedures recommended by Boeing to successfully implement IAN.

The Boeing Flight Crew Training Manual (FCTM) has an excellent section addressing IAN, and I recommend you read it to gain a greater understanding of how the IAN system functions.

The Navigation Performance Scales (NPS), which augment IAN, will not be discussed. NPS will form part of a future article. Information in this article relates to FMC software U10.8A.

Overview

Integrated Approach Navigation (IAN) derives information from an approach type selected from the Flight Management Computer (FMC) database to generate a 3 degree glide path from the Final Approach Fix to the threshold of the runway. In so doing, it displays visual cues similar to the Instrument Landing System (ILS). Flight path guidance is derived from the FMC, navigational radios, or combination of both.

To use IAN, an approach with a glide path must be selected from the FMC database. The approach must include a series of waypoints that depict a vertical profile that includes a glide path.

An IAN approach may be flown with a single autopilot, raw data, or by following the visual cues displayed on the Flight Director (FD).

IAN is an airline option, and although not every airline carrier will have IAN as part of their avionics suite, the technology is becoming more popular as the safety and economic benefits of IAN are understood by airline carriers.

Geometric Path (Glide Path)

An IAN Approach approximates a 3 degree glide path (descent profile) from the Final Approach Fix (FAF) to approximately 50 feet above the runway threshold. Although, the glide path may not comply with altitude constraints in the FMC prior to the FAF, the generated glide path will always be at or above the altitude constraints between the FAF and the Missed Approach Point (MAP) displayed in the FMC.

Critically, an IAN approach is a Category I Non Precision Approach (NPA) and is not to be confused with an ILS Precision Approach. Therefore, NPA procedures must be adhered to when initiating an approach using IAN.

Although the automation provided by IAN will guide an aircraft (in most cases) to the threshold of the runway, IAN has not been designed to do this. Rather, IAN has been designed to guide the aircraft to the MAP published on the approach chart. The flight crew will then disengage IAN by disengaging the autopilot and autothrottle and fly the remainder of the approach manually as per NPA protocols.

In some instances, the final approach course (FAC) is offset from the runway center line and manoeuvring the aircraft for direct alignment will be necessary, whilst following the glide path angle.

Although the final approach is very similar to an ILS approach, IAN does not support autoland; if the aircraft is not in a stable configuration and you are not visual with the runway at or beyond the MDA, a missed approach procedure (Go-Around) should be executed.

Consistency in Procedures (eighteen approach types to one)

The introduction of IAN has condensed the number of approach types (and differing procedures) to one consistent procedure; minimising the amount of time an airline needs to train pilots in numerous approach types. Time is money and utilising advanced technology such as IAN can increase airline productivity and safety.

Approach Types

IAN can be used for the following approach types:

RNAV
RNAV (RNP) – (provided there are no radius to fix legs)
NDB and VOR
GPS & GNSS
LOC, LOC-BC, TACAN, LDA SDF (or similar style approaches)

Note that if using IAN to execute a Back Course Localiser approach (B/C LOC), the inbound front course must be set in the MCP course window.

During the approach you must monitor raw data and cross check against other navigational cues. Furthermore, although the use of IAN is recommended only for straight-in approaches, line use suggests that flight crews routinely engage IAN up to, but not exceeding 45 degrees from the runway approach course.

IAN is compatible with several approach types, however, being compatible does not necessarily mean that every approach type in the FMC is suitable.

Since IAN was introduced, additional approaches have been developed and added to the RNAV family; in particular, RNAV (RNP) approaches, that use ‘radius to fix’ (RF) to generate a curved path that terminates at a location where an approach procedure begins. These approaches have been designed to optimise airspace and usually have tight separation requirements; to fly these approaches an aircraft is required to have additional on-board navigation performance monitoring and alerting equipment.

These approach charts are identified by the title RNAV (RNP) RWY XX and the letters AR (Authorisation Required) in the description of the chart.

These approaches and are not suitable to use with IAN; they should be flown with LNAV/VNAV.

Recommended Approach Types

The best approach to use with IAN are straight-in or near straight-in approaches. VOR, LOC, NDB, RNAV and RNAV (GNSS) approaches work especially well as these approaches usually provide relatively long straight-in legs.

IAN can be used on an RNP (AR) approaches as long as there are no RF turns involved (straight-in approach only). If flying such an approach you should be aware that the legs can be quite short and IAN may arm and engage quite late in the approach profile.

Important Point:

The use of IAN is not authorised for a RNAV (RNP-AR) approach.

Using IAN – General

IAN does not need to be specifically ‘turned on’ for it to function; the functionality, if installed in the aircraft, is always operational. When the aircraft is within range of the designated approach, the runway data and/or Deviation Pointers will annunciate and be displayed on the PFD. At any time after this point has been reached, IAN can be armed and or engaged by pressing the APP button on the MCP.

Navigation Radios and Radio Frequencies

For an IAN approach to function, an approach procedure with a glide path must be selected from the FMC database. Although selection of navigation radios is not mandatory, selection is recommended, as correct tuning of the radios can provide increased visual awareness and redundancy, should a CDU failure occur, or there be a corruption of the data in the FMC.

Boeing strongly advise to tune the radios to the correct localiser frequency for the approach. This eliminates the possibility of the radio picking-up another approach from a nearby airport (and providing erroneous data to the crew). The ILS frequency must never be used with an IAN approach (unless the glideslope is inoperative). In the case of an inoperative glideslope, the G/S prompt in the CDU must be selected to OFF to ensure that the FMC generated glide path is flown.

Minimum Descent Altitude (MDA)

As mentioned, an IAN approach is a NPA, and when authorised by the Regulatory Authority non-ILS approaches can be flown to a published VNAV Decision Altitude/Height (DA/H) or to a published MDA (the MDA is used as a decision altitude). If not authorised to use the MDA as a decision altitude, crews must use the MDA specified for the approach flown.

To comply with the MDA protocols during a constant angle approach where a level off is not planned at the MDA, it is necessary to add +50 feet to the published MDA. This enables an adequate buffer to prevent incursion below the MDA and adhere to the NPA protocols.

Important Points:

IAN uses the FMC database to generate a 3 degree glide path from the FAF to the runway threshold. IAN does not require the navigation radios to be tuned. However, it is recommended to tune the radios.
Some approaches in the FMC database have a number of glide paths displayed with differing altitudes. When presented with this scenario, always select the first glide path and altitude.

IAN approach to RJAA **ILS X** or **LOC X** Rwy 16L. The localiser has been captured and the FMA displays FAC in green, while G/P is armed (FMA G/P white). The vertical Deviation Pointer is displayed as an outlined magenta-coloured diamond (anticipation pointer) while the localiser is displayed as solid magenta (because FAC has been captured). The source of the runway data is from the FMC (ProSim737 avionics suite)

Using IAN - IAN Annunciations and Displays

IAN can display several visual cues to alert you to the status of the IAN system. The cues are triggered at various flight phases and are displayed on the attitude display of the Primary Flight Display (PFD) and on the Flight Mode Annunciator (FMA).

Runway Data: Runway data (runway identifier, approach front course, approach type and distance to threshold) is displayed in the top left area on the PFD when either the localiser or the selected FMC approach is in range of the runway.

IAN approach to RJAA **ILS X** or **LOC X** Rwy 16L. The localiser and glide path have been captured. The FMA displays FAC and G/P in green and SINGLE CH is displayed. The Deviation Pointers, previously in outline (Figure above), are now solid filled. The aircraft will descent on the glide path to the threshold of the runway (ProSim737 avionics suite)

If the source of the runway data is the navigation radio, then this information will be displayed when the radio is in range of the localiser. However, if the primary data source is from the FMC (radio not tuned) the runway data will be displayed only after IAN has engaged. When IAN engages, the runway data will be sourced from the FMC. This will be evident as the approach type will be displayed on the PFD.

The approach type (LNAV, FMC, LOC, ILS etc) displayed will depend on what type of approach has been selected from the FMC database.

Approach Guidance: Approach guidance (Deviation Pointers) are displayed on the PFD whenever IAN is in range of the runway. When the Deviation Pointers are displayed, IAN can be used.

Final Approach Course (FAC): The letters FAC are displayed on the center FMA when IAN is armed.

It stands to reason, that FAC (lateral guidance) usually annunciates prior to G/P (vertical guidance), but depending on the position of the aircraft when APP in pressed, both annunciations may be displayed at the same time.

Glide Path (G/P): The letters G/P are displayed on the right FMA when IAN is armed.

FMA FAC and G/P Colours: Two FMA colours are used. White indicates that the FAC or G/P is armed. The colour of the FMA display will change from white to green when the aircraft captures either the localiser or glide path.

Mode Control Panel (MCP): Arming IAN (pressing the APP button on the MCP) will cause the letters APP on the MCP to be illuminated in green. The APP light will extinguish when IAN captures the glide path.

Lateral and Vertical Guidance Deviation Pointers: Deviation Pointers display the lateral and vertical position of the aircraft relative to the final approach course of the selected runway. The lateral pointer represents the localiser while the vertical pointer represents the glide path. The pointers are displayed whenever IAN is in range of the runway.

The pointers will initially be displayed as either magenta or white-coloured outlined diamonds. When the aircraft captures either the localiser or glide path, (2 1/2 dots from center) the pointer (s) will change from an outline, to a solid-filed magenta-coloured diamond.

Whether the initial colour of the diamonds is magenta or white depends on which pitch/roll mode has been selected when the aircraft comes into range.

Although the correct name for the pointers is Deviation Pointers, they are often called anticipation pointers, anticipation cues or ghost pointers (ghost pointers being an 'Americanism').

During an IAN approach:

The deviation alerting system will self-test when passing through 1500 feet radio altitude. The self-test will generate a two-second FAC deviation alerting display on each PFD (the pointers will flash in amber); and,
If the autopilot is engaged, and at low radio altitudes, the scale and Deviation Pointers will turn amber and begin to flash if the deviation from either the localiser or glide path is excessive.

SINGLE CH: SINGLE CH will be displayed in green, when the aircraft captures the glide path (both the localiser and glide path). At this time, the Deviation Pointers will change from white-coloured outlines to solid magenta-coloured diamonds. FAC and G/P on the FMA will also be in green. Additionally, the illuminated APP button on the MCP will extinguish. At this point, the aircraft will be guided automatically along the glide path.

Flight Mode Annunciations (FMA): The FMA display will vary depending on the source of the navigation guidance used for the approach.

For localiser-based approaches (LOC, LDS, SDF and ILS (glideslope OUT), the FMA will display VOR/LOC and G/P. For B/C LOC approaches, the FMA will display B/CRS and G/P.

If lateral course guidance is derived from the FMC (RNAV, GPS, VOR, NDB and TACAN approaches), the FMA will display FAC and G/P.

Ground Proximity Warning System (GWPS) Aural Warnings and Displays: GWPS warnings will annunciate if at any time the aircraft deviates below the glide path, and failure to disengage IAN at the appropriate altitude will trigger a GPWS aural warning alert ‘autopilot autopilot’ at 100 feet radio altitude. This is in addition, to the words ‘autopilot’ being displayed on the PFD.

Using IAN – At What Distance Does IAN Work

IAN is not designed to navigate to the airport and its functionality will only be available when the aircraft is in range of the airport runway; for a straight-in approach, this is at approximately 20 nautical miles. However, this distance can be considerably less if the aircraft is not on a straight-in course to the runway.

Important Point:

To give you the longest time from which to transition to an IAN approach, try to choose a suitable approach type (from the FMC) that exhibits a ‘more or less’ straight-in approach.

Using IAN – When to Arm and Engage IAN

IAN can be armed at anytime after the Deviation Pointers are displayed on the PFD.
To arm/select IAN, the flight crew press the APP button on the Mode Control Panel (MCP) similar to performing an ILS approach.
IAN is armed only after clearance for final approach has been received from Air Traffic Control (ATC). By this time, the aircraft is probably on a straight-in approach.
IAN cannot be used for STARS and is not designed to be engaged when the aircraft is ‘miles’ from the designated runway. Transition to an IAN approach can be from any of several pitch/roll modes.
IAN (if armed) engages automatically when the either the localiser or glide path is captured.

IAN should only be armed or engaged when:

The guidance to be used for the final approach is tuned and identified on the navigation radio;
An approach has been selected from the FMC database that has a 3 degree glide path;
The appropriate runway heading is set in the course window in the MCP;
The aircraft is on an inbound intercept heading;
ATC clearance for the approach has been received; and,
The approach guidance information is displayed on the PFD along with the lateral and vertical Deviation Pointers.

Disengaging IAN

IAN is either armed, engaged or not engaged.

If you want to disarm IAN from the arm mode, it is a matter of pressing the APP button on the MCP; the light on the APP button will extinguish and the Deviation Pointers on the PFD will not be visible.

If you want to disengage IAN after it has captured either the localiser or glide path (or both), pressing the APP button on the MCP will do nothing. In this scenario, to disengage IAN you will need to conduct a Go-Around by selecting TOGA, or change the pitch/roll mode (i.e. Level Change).

Disconnecting the autopilot and flying manually will also disengage IAN; the upside being that the Deviation Pointers will remain displayed on the PFD, until a different pitch/roll mode is selected.

Important Points:

If the navigation radio is not tuned to the localiser, the runway data will not be displayed until IAN is engaged, however, the Deviation Pointers will be displayed.
IAN can be armed whenever the aircraft is in range of the runway - in other words whenever the Deviation Pointers are displayed on the PFD.
When IAN is armed, the FAC and G/P display on the FMA is coloured white.
When IAN is engaged (localiser or glide path) the FAC and G/P on the FMA is coloured green.
IAN will only engage after capture of either the lateral (FAC) or vertical glide path (G/P).
When IAN has captured the glide path, SINGLE CH will be displayed in green in the PFD.

Using IAN - Set-Up and Procedure

The following procedures used for an IAN approach are derived from ILS procedures and are consistent for all approach types.

Select the appropriate approach to use from the FMC database. Ensure that the selected approach has a glide path. Do not alter any of the approach constraints.
Set the altitude of the glide path (from the FMC) in the MCP altitude window.
Fly the aircraft in whatever pitch/roll mode to the Initial Approach Fix (IAF). Remember straight-in approaches are best, although offsets between 25 and 45 degrees may be used but not recommended.
Configure the navigation radios to the correct frequency based on the approach type you have selected from the FMC database. Do not use an ILS frequency.
Set the barometric minimums to the altitude published on the approach chart. Add 50 feet to avoid breaking NPA protocols.
Set the correct runway approach course in the MCP course window.
Do not select IAN (press the APP button) until the aircraft is in the correct position relative to the approach course.
When approximately 2 miles from the FAF - GEAR DOWN, FLAPS 15, SPEED CHECK.
At glide path capture (FAF) – FLAPS 25/30 (landing flaps), SPEED CHECK.
At 300 Feet below glide path capture, reset the MCP altitude window to the missed approach altitude. Failure to wait until the aircraft descends 300 feet will cause the ALT HOLD annunciation to display and the aircraft levelling off.
At minima – Disengage autopilot and autothrottle, manually align aircraft to the runway, and follow the Deviation Pointers and Flight Director (FD) cues to the runway threshold. Maintain the glide path to the flare and do not descend below the displayed glide path.

Although glide path guidance can be used as a reference once the aircraft descends below the MDA, the primary means of approach guidance is visual. If not visual at the MDA, execute a Go-Around. Remember, using IAN is a NPA.

Important Points:

When using IAN the aircraft should be configured approximately 2 nautical miles from the FAF (this is one of the fundamental differences between an IAN approach and an ILS approach).
Often, the runway may not be aligned with the FMC generated course. The FCTM states; ‘If the final approach course is offset from the runway centreline, manoeuvring to align with the runway centreline is required. When suitable visual reference is established, continue following the glide path angle while manoeuvring to align with the runway.
Flying an IAN approach is an NPA; it is important to fly visually after passing the MDA.
The approach mode (APP on center CTR knob) on the EFIS can be selected when using IAN. This will display the IAN approach on the Navigation Display as if it is an ILS approach.

Transitioning to an IAN Approach

A flight crew will usually transition to an IAN approach 2 nautical miles prior to the Initial Approach Fix (IAF).

At this distance from the runway there is not a lot of time to configure the aircraft for landing, and if IAN engages when the aircraft is either above or below the glide path, there is a possibility that the aircraft will abruptly and unexpectedly ascend or descend as the automation attempts to capture the glide path. Therefore, you must be in diligent that the aircraft’s altitude roughly matches the position of the Deviation Pointers when close to the FAF.

Techniques to Transition Smoothly to an IAN Approach

There are several techniques that can be used to ensure a smooth transition to an IAN approach.

By far the easiest technique to ensure a seamless transition without any abrupt lateral or vertical deviation, is to position the aircraft ‘more or less’ within one dot deviation of the localiser or glide path (Deviation Pointers) prior to selecting IAN.

In this way you can follow (‘fly’) the Deviation Pointers and engage IAN when the aircraft is more or less aligned with the position of the pointers (similar to how an ILS approach is carried out).

Another technique, is to fly the aircraft until ALT HOLD is displayed in the FMA (assuming that the altitude set in the altitude window in the MCP is approximately 2 nautical miles from the FAF). Then select IAN. This should enable the aircraft to smoothly capture the glide path when reaching the FAF.

Importantly, if transitioning to IAN from VNAV, it is prudent to engage SPD INTV to manually control MCP speed.

**FIGURE 1:** Visual representation of an IAN approach and transition from roll mode. (*Copyright Boeing FCTM).*

Increased Spatial Awareness

Any approach can be busy and it is easy to forget something. Therefore, it is wize to create a circle at 2 miles from the FAF that can be displayed on the Navigation Display (NP).

One way to accomplish this is by using the FIX page in the CDU.

In the LEGS page copy to the scratchpad the FAF (click the line on which the FAF is located). Open the FIX page and upload the FAF (from the scratchpad) to the FIX entry. To create a dashed circle at 2 nautical miles from the FAF, enter /2 to Line Select Left 1.

Important Points:

Maintaining the correct approach speed and altitude is paramount to a successful IAN approach. If the aircraft is travelling too fast, slowing down after IAN has engaged can be difficult. Likewise, if the aircraft is too high and IAN engages, the vertical descent can be steep as the aircraft attempts to follow the FMC generated glide path.
You must be vigilant and anticipate actions and events before they occur.

Using IAN - Situations To Be Attentive Of

Automation can have its pitfalls and IAN is no different. However, once potential shortcomings are known, it is straightforward to bypass them. The most common mistake, especially with virtual pilots, is not following the correct procedure.

Possible 'surprises' associated with an IAN approach are:

1. Failing to configure the aircraft prior to IAN engaging in FAC and G/P mode.

Unlike an ILS approach, where configuration for landing is initiated when the aircraft captures the glideslope (usually some distance from the runway) during an IAN approach configuration for landing is initiated approximately 2 nautical miles from the FAF.

If you have not configured the aircraft for landing prior to the capture of the glide path, there may be insufficient time for you to complete recommended actions and checklists.

If you believe this will occur, there is no reason why configuration cannot occur at an earlier stage.

2. Forgetting to set the Missed Approach Altitude (MAA) in the MCP.

Failing to wait until the aircraft has descended 300 feet below the glide path capture altitude to reset the MCP altitude to the MAA. Failure will cause the ALT HOLD annunciation to display and the aircraft leveling off.

3. Approaching the runway while not on the correct intercept course.

IAN operates flawlessly with straight-in approaches and to a certain extent with approaches up to 45 degrees from the main approach course, however, IAN will not engage if you approach the assigned runway at 90 degrees. Nor will IAN engage if you are attempting to fly a STAR.

4. Forgetting to set the initial glide path altitude in the MCP (from the FMC).

A common mistake is not setting the glide path altitude (from the FMC) in the MCP window when configuring the aircraft for an IAN approach.

ProSim737 and IAN

Installing IAN to ProSim-AR Avionics Suite

IAN forms part of the avionics suite, however, for IAN to function it needs to be selected (turned on) in the ProSim-AR IOS (Instructor Operator Station). The same is for the Navigation Scales (if required).

To turn on IAN, open IOS: Settings/Cockpit Setup Options/Options and place a tick in the appropriate box beside IAN. A restart of the ProSim-AR main module may be required for the change to take effect.

IAN was introduced to the ProSim737 avionics suite in December 2014. For the most part, the functionality is reliable and operates as it should (see note 1).

As at writing, known issues are as follows (this may change with Version 3 software updates):

ProSim737 does not display the IAN runway data immediately following the engagement of TO/GA during the take-off roll.

This is incorrect. In the real aircraft, this information is displayed immediately following the engagement of TO/GA during the take-off roll while. (further research required)

The colour of the approach guidance display (LNAV/VNAV) after TO/GA is engaged is currently white. This is incorrect. The colour should be green.
At 100 feet AGL, if IAN is engaged and the autopilot remains selected, a flashing AUTOPILOT warning in amber colour will be displayed on the PFD. This is correct. However, an audible ‘autopilot’ callout should also be heard. This is not simulated.

Important Point:

ProSim737 users should also note, that for IAN to function within the avionics suite, it must be selected in the cockpit set-up page of the Instructor Station (IOS).

Note 1: IAN works flawlessly for straight-in approaches (or approaches that are slightly offset). However, the ProSim software when using some RNAV (RNP) approaches has trouble maintaining the correct vertical profile.

When a RNAV (RNP) approach (not AR) is selected, IAN arms and engages very late in the approach profile (after the FAF). The altitude that IAN engages is well below the profile used in VNAV; this results in the aircraft diving to capture the IAN glide path. Once the aircraft is established on the glide path IAN works as it is supposed to.

The above scenario does not occur with every VNAV (RNP) approach; only those that exhibit a curved radius to fix (RF) profile or short leg profile to the runway threshold.

In the real aircraft (depending on operator and country of operation) IAN can handle all RNAV (RNP) approaches with the exception of RNAV (RNP-AR) approaches.

In comparison, Precision Manuals Development Team (PMDG) NGX and NGXu can fly the above approaches in IAN. This has been achieved by artificially replicating the approach using various hidden ‘waypoints’ that their software can read. In effect, what you are seeing is the aircraft flying over the waypoints that have been overlaid onto the curves in the approach.

I do not believe ProSim has replicated PMDG’s methodology in their software.

Therefore, if flying an RNAV (RNP) approach using IAN, select only those approaches that are ‘more or less’ straight-in without RF curves or turns; otherwise, use LNAV/VNAV.

BELOW: Montage of four screen captures of the PFD showing some of the displays generated during an IAN approach (images upper left to right then bottom left to right). Images 1-3 are sequential. Image 4 is standalone.

Image 1: Aircraft is LNAV/VNAV approaching the IAF. The aircraft is too far from the runway for IAN to be in range to operate (RJAA VOR Rwy 16R).

Image 2: Aircraft is in range of RJAA localiser (tuned in the navigation radio). Runway data is displayed from localiser and Deviation Pointers are displayed in outlined white-coloured diamonds (anticipation pointers). The Deviation Pointers will change from white (outline) to magenta (either outline or solid) when either the localiser or glide path is captured. FAC and G/P are displayed on the FMA in white indicating that IAN has been armed. Note that if IAN was not armed, only the runway data and Deviation Pointers would be displayed (RJAA VOR Rwy 16R).

Image 3: IAN has captured the localiser and the lateral Deviation Pointer is displayed as a solid magenta-coloured diamond. FAC (in green) is displayed on the FMA. The vertical Deviation Pointer is still in outline and in white (anticipation pointer), as is the G/P on the FMA. IAN is tracking the localiser (RJAA VOR Rwy 16R).

Image 4: IAN has engaged. The runway data is now sourced from the FMC and not the localiser (as in the above examples). The FMA displays FAC and G/P in green colour, SINGLE CH is displayed, and both Deviation Pointers are solid magenta-coloured diamonds. IAN has captured the Glide Path (RJAA ILS X or LOC X Rwy 16L).

Montage of four screen captures of the PFD showing some of the displays generated during an IAN approach (images upper left to right then bottom left to right). Images 1-3 are sequential. image 4 is standalone
**Image 1:** Aircraft is LNAV/VNAV approaching the IAF. The aircraft is too far from the runway for IAN to be in range to operate (RJAA VOR Rwy 16R).
**Image 2:** Aircraft is in range of RJAA localiser (tuned in the navigation radio). Runway data is displayed from localiser and Deviation Pointers are displayed in outlined white-coloured diamonds (anticipation pointers). The Deviation Pointers will change from white (outline) to magenta (either outline or solid) when either the localiser or glide path is captured. FAC and G/P are displayed on the FMA in white indicating that IAN has been armed. Note that if IAN was not armed, only the runway data and Deviation Pointers would be displayed (RJAA VOR Rwy 16R).
**Image 3:** IAN has captured the localiser and the lateral Deviation Pointer is displayed as a solid magenta-coloured diamond. FAC (in green) is displayed on the FMA. The vertical Deviation Pointer is still in outline and in white (anticipation pointer), as is the G/P on the FMA. IAN is tracking the localiser (RJAA VOR Rwy 16R).
**Image 4:** IAN has engaged. The runway data is now sourced from the FMC and not the localiser (as in the above examples). The FMA displays FAC and G/P in green colour, SINGLE CH is displayed, and both Deviation Pointers are solid magenta-coloured diamonds. IAN has captured the Glide Path (RJAA ILS X or LOC X Rwy 16L)

Videos of IAN Approach

IAN APPROACH IN SIMULATOR

IAN APPROACH IN REAL 737-800 AIRCRAFT

Final Call

The use of Global Positioning Systems has enabled stabilised approaches at many airports, and the IAN system can take advantage of this technology to provide intuitive displays that support stabilised approaches on a consistent basis.

Aircraft fitted with IAN are capable of using the APP button located on the MCP to execute an instrument ILS-style approach based on flight path guidance from the FMC. This makes Non Precision Approaches easier to execute with increased safety. It also enables a constant descent angle, less engine spooling, wear and tear, and improved passenger comfort. Furthermore, IAN uses a standardised and consistent procedure, that in addition to improved displays and alerts, can be used in place of LNAV/VNAV.

Nevertheless, a flight crew must be vigilant when using any automation, especially during the critical approach phase where there is little margin for error. First and foremost is the innate ability to fly the airliner manually, and although automation such as IAN can enhance safety, it does so at the detriment of manual flying skills.

References

Several sources were used to obtain the information documented in this post, including: personal communication with a B737-800 pilot, the Boeing Flight Crew Training Manual and the Boeing 737 Technical Guide by Chris Brady.

If any discrepancies are noted in this article, please contact me so they can be rectified.

Acronyms and Glossary

AGL – Above Ground Level
APP – Approach button located on MCP
CDU – Control display Unit (glorified keyboard)
EFIS – Electronic Flight Instrument Display
FAC – Final Approach Course
FAF – Final Approach Fix
FMA – Flight Mode Annunciator
FMC – Flight Mode Computer
FMS – Flight Management System
G/P – Glide Path (Non Precision Approach / NPA)
G/S – Glideslope (Precision Approach / PA)
IAF – Initial Approach Fix
IAN – Integrated Approach Navigation
ILS – Instrument Landing System
IMC – Instrument Meteorological Conditions
MAP – Missed Approach Point
MCP – Mode Control Panel
MDA - Minimum Descent Altitude
ND – Navigation Display
PFD – Primary Flight Display
RA – Radio Altitude
RF – Radius to fix
RNAV (RNP-AR) Approach - RNP-AR is a subset of an RNAV approach that requites authorization (RA) to fly
Select – To select , arm or engage something
STAR - Standard Terminal Arrival Route

Review and Updates

25 August 2017 - Review and content updated.
03 December 2019 - Review and content updated.
29 October 2019 - Review and content updated.
28 April 2021 - Review and content updated. Release of .pdf.
21 December 2022 - Updated to latest procedure changes.

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November 01, 2014

B737-600 NG Fire Suppression Panel (Fire Handles) - Evolutionary Conversion Design

November 01, 2014/ Flaps 2 Approach

737-600 Next Generation Fire Suppression Panel installed to center pedestal. The lights test illuminates the annunciators

737-600 NG Fire Suppression Panel light plate showing installed Phidget and Phidgets relay card

Originally used in a United Airlines 737-600 Next Generation aircraft and purchased from a wrecking yard, the Fire Suppression Panel has been converted to use with ProSim737 avionic suite. The panel has full functionality replicating the logic in the real aircraft.

This is the third fire panel I have owned. The first was from a Boeing 737-300 which was converted in a rudimentary way to operate with very limited functionality - it was backliut and the fire handles lit up when they were pulled. The second unit was from a 737-600; the conversion was an intermediate design with the relays and interface card located outside the unit within the now defunct Interface Master Module (IMM). Both these panels were sold and replaced with the current 600 Next Generation panel. This panel is standalone, which means that the Phidget and relay card are mounted within the panel, and the connection is via the Canon plugs and one USB cable.

I am not going to document the functions and conditions of use for the fire panel as this has been documented very well in other literature. For an excellent review, read the Fire Protection Systems Summary published by Smart Cockpit.

Nomenclature

Before going further, it should be noted that the Fire Suppression Panel is known by a number of names: fire protection panel, fire control panel and fire handles are some of the more common names used to describe the unit.

Panel with outer casing removed showing installation of Phidget and and relays. Ferrules are used for easier connection of wires to the Phidget card. Green tape has been applied to the red lenses to protect them whilst work is in progress

Plug and Fly Conversion

What makes this panel different from the previously converted 737-600 panel is the method of conversion.

Rear of panel showing integration of OEM Canon plugs to supply power to the unit (5 and 28 volts). The USB cable (not shown) connects above the middle Canon plu

Rather than rewire the internals of the unit and connect to interface cards mounted outside of the unit, it was decided to remove the electronic boards from the panel and install the appropriate interface card and relays inside the unit. To provide 5 and 28 volt power to illuminate the annunciators and backlighting, the unit uses the original Canon plugs to connect to the power supplies (via the correct pin-outs). Connection of the unit to the computer is by a single USB cable. The end product is, excusing the pun - plug and fly.

Miniaturization has advantages and the release of a smaller Phidget 0/16/16 interface card allowed this card to be installed inside the unit alongside three standard relay cards. The relays are needed to activate the on/off function that enables the fire handles to be pulled and turned.

The benefit of having the interface card and relays installed inside the panel rather than outside cannot be underestimated. As any serious cockpit builder will attend, a full simulator carries with it the liability of many wires running behind panels and walls to power the simulator and provide functionality. Minimising the number of wires can only make the simulator building process easier and more neater, and converting the fire handles in this manner has followed through with this philosophy.

Complete Functionality including Push To Test

The functionality of the unit is only as good as the flight avionics suite it is configured to operate with, and complete functionality has been enabled using the ProSim737 avionics suite.

One of the positives when using an OEM Fire Suppression Panel is the ability to use the push to test function for each annunciator. Depressing any of the annunciators will test the functionality and cause the 28 volt bulb to illuminate. This is in addition to using the lights test toggle located on the Main Instrument Panel (MIP) which illuminates all annunciators simultaneously.

At the end of this post is a short video demonstrating several functions of the fire panel.

The conversion of this panel was not done by myself. Rather, it was converted by a gentleman who is debating converting OEM fire panels and selling these units commercially; as such, I will not document how the conversion was accomplished as this would provide an unfair disadvantage to the person concerned.

Differences - OEM verses Reproduction

There are several reproduction fire suppression panels currently available, and those manufactured by Flight Deck Solutions and CP Flight (Fly Engravity) are very good; however, pale in comparison to an OEM panel. Certainly, purchasing a panel that works out of the box has its benefits; however the purchase cost of a reproduction panel is only marginally less that using a converted OEM panel.

By far the most important difference between an OEM panel and a reproduction unit is build quality. An OEM panel is exceptionally robust, the annunciators illuminate to the correct light intensity with the correct colour balance, and the tension when pulling and turning the handles is correct with longevity assured. I have read of a number of users of reproduction units that have broken the handles from overzealous use; this is almost impossible to do when using a real panel. Furthermore, there are differences between reproduction annunciators and OEM annunciators, the most obvious difference being the individual push to test functionality of the OEM units.

737-300 Fire Suppression Panel. Note the different location of korrys

Classic verses Next Generation Panels

Fire Suppression Panels are not difficult to find; a search of e-bay usually reveals a few units for sale. However, many of the units for sale are the older panels used in the 737 classic aircraft.

Although the functionality between the older and newer units is almost identical, the similarity ends there. The Next Generation panels have a different light plate and include additional annunciators configured in a different layout to the older classic units.

737-300 Fire Suppression Panel. this panel is slightly different to the above panel as it has extra korrys for moreadvanced fire logic

One of the reasons that Next Generation panels are relatively uncommon is that, unless unserviceable, the panels when removed from an aircraft are sold on and installed into another aircraft.

Video

The video demonstrates the following:

Backlighting off to on (barely seen due to daylight video-shooting conditions)
Push To Test from the MIP (lights test)
Push To Test for individual annunciators
Fault and overhead fire test
Switch tests; and,
A basic scenario with an engine 1 fire.

NOTE: The video demonstrates one of two possible methods of deactivating the fire bell. The usual method is for the flight crew to disable the bell warning by depressing the Fire Warning Cut-out annunciator located beside the six packs (part of the Master Caution System) on the Main Instrument Panel (MIP). An alternative method is to depress the bell cut-out bar located on the Fire Suppression Panel.

737-600 Fire Suppression Panel

September 02, 2014

B737 Autothrottle (A/T) - Normal and Non-Normal Operations

September 02, 2014/ Flaps 2 Approach

Mode Control Panel (MCP) showing A/T on/off solenoid switch and speed window. The MCP shown is the Pro model manufactured by CP Flight in Italy

The Autothrottle (A/T) is part of the Automatic Flight System (AFS) comprising the Autopilot Flight Director System (AFDS) and the autothrottle. The A/T provides automatic thrust control through all phases of flight.

The autothrottle functionality is designed to operate in unison with the Autopilot (A/P), Nevertheless, a flight crew will not always adhere to this use, some crews preferring to fly manually or partially select either the autopilot or autothrottle.

A search on aviation forums will uncover a plethora of comments concerning the use of the autothrottle which, combined with autopilot use and non-normal procedures, can be easily be misconstrued. An interesting discussion can be read on PPRuNe.

This post will examine, in addition to normal A/T operation, some of the non-normal conditions, their advantages and possible drawbacks. Single engine operation will not be addressed as this is a separate subject.

Additional Information:

737 Automatic Systems Review (Smart Cockpit).

Autothrottle (A/T) Use

The autothrottle is engaged whenever the A/T toggle is armed and the speed annunciator is illuminated on the Mode Control Panel (MCP). Either of these two functions can be selected together or singularly.

The autothrottle is usually engaged during the takeoff roll by pressing the TO/GA buttons located under the thrust lever handles. This is done when %N1 stabilises for both engines at around 40%N1. This will engage the autothrottle in the TO/GA command mode. The reason the autothrottle is used during takeoff is to simplify thrust procedures during a busy segment of the flight.

FMA Captain-side PFD showing TO/GA annunciated during takeoff roll

Once engaged, the TO/GA command mode will control all thrust outputs to the engines until the mode is exited, either at the designated altitude set on the MCP, or by activating another automaton mode such as Level Change (LVL CHG). When TO/GA is engaged, the Flight Mode Annunciator (FMA) will announce TO/GA providing a visual cue.

The use of the autothrottle is at the discretion of the pilot flying, however, airline company policy often dictates when the crew can engage and disengage the A/T.

The Flight Crew Training Manual (FCTM) states:

‘A/T use is recommended during takeoff and climb in either automatic or manual flight, and during all other phases of flight’.

When to Engage / Disengage the Autothrottle

A question commonly asked is: ‘When is the autothrottle disengaged and in what circumstances’ Seemingly, like many aspects of flying the Boeing aircraft, there are several answers depending on who you speak to or what reference you read.

In the FCTM, Boeing recommends the autothrottle be used only when the autopilot is engaged (autopilot and autothrottle coupled).

In general, a flight crew should disengage the autothrottle system at the same time as the autopilot. This enables complete manual input to the flight controls and follows the method recommended by Boeing.

My preference during an approach is to disconnect the autothottle and autopilot no later than 1500 feet AGL. This corresponds to the altitude that the aircraft must be in landing configuration, gear down, flaps 30 and within vertical and lateral navigation constraints with landing checks completed. Disconnecting the autothrottle and autopilot earlier in the approach provides additional time to transition from automated flight to manual flight, and establish a 'feel' for the aircraft before landing.

It's not uncommon that flight crew will manually fly the aircraft, especially 'old school' pilots who are very conversant with hand flying. I know some crews that will fly from 10,000 feet to landing using the Flight Director (FD), ILS, VNAV and LNAV cues on the Primary Flight Display (PFD) for guidance and the information displayed on the Navigation Display (ND) for situational awareness. Many pilots enjoy hand-flying the aircraft during the approach phase.

Important Point:

Whenever hand flying the aircraft with the autothottle not engaged, it's very important to monitor the airspeed. This is especially so during the final approach, when thrust can easily decay to a speed very close to stall speed.

The Autothrottle is Designed to be used Coupled with the Autopilot

The autothrottle is a sophisticated automated system that will continually update thrust based on minor pitch and attitude changes, and operates exceptionally well when coupled with the autopilot. But, when the autopilot is disengaged and the autothrottle retained, its reliability can be questionable.

Some crews believe that if a landing is carried out with the autopilot off and the autothrottle engaged, and a fall in airspeed occurs, such as during the flare, then the autothrottle will apply thrust causing the potential for a tail strike. Likewise, if during the approach there are excessive wind gusts, pitch coupling (discussed below) may occur.

The advantages of using the autothrottle and autopilot together are:

(i) Speed is stabilized;

(ii) Speed floor protection is maintained;

(iii) Task loading is reduced; and,

(iv) Flight crews can concentrate on visual manoeuvring and not have to be overly concerned with wind additives

The disadvantages of using the autothrottlewithout the autopilot engaged are:

(i) Additional crew workload and possible loss of situational awareness (due to workload);

(ii) Potential excessive and unexpected throttle movement caused by pitch and attitude changes;

(iii) Potential excessive airspeed when landing in windy conditions with gusts;

(iv) The potential for pitch coupling to occur (discussed below); and,

(v) A loss of thrust awareness (out of the loop).

Important Point:

The autopilot and autothrottle should not be used independent of one another.

Boeing 737 Design

The design of the 737 airframe is prone to pitch coupling because of its under wing mounted engines. The engine position causes the thrust vector to pitch up with increasing thrust and pitch down with a reduction in thrust.

The autothrottle is designed to operate in conjunction with the autopilot, to produce a consistent aircraft pitch under normal flight conditions. If the autopilot is disengaged but the autothrottle remains engaged, pitch coupling may develop.

Pitch Coupling

Pitch coupling is when the autothrottle system actively attempts to maintain thrust based on the pitch/attitude of the aircraft. It occurs when the autopilot is not engaged and manual inputs (pitch and roll) are used to control the aircraft.

If the pitch inputs are excessive, the autothrottle will advance or retard thrust in an attempt to maintain the selected MCP speed. This coupling of pitch to thrust can be potentially hazardous when manually flying an approach, and more so in windy conditions.

Scenario - pitch coupling

For example, imagine you are in level flight with autothrottle engaged and the autopilot not engaged, and a brief wind change causes a reduction in airspeed. The autothrottle will slightly advance the throttles to maintain commanded speed. This in turn will cause the aircraft to pitch slightly upwards, triggering the autothrottle to respond to the subsequent speed loss by increasing thrust, resulting in further upward pitch. The pilot will then correct this by pushing forward on the control column to decease pitch. As airspeed increases, the autothrottle will decrease thrust causing the aircraft to decrease more in pitch.

The outcome is that a coupling between pitch and thrust will occur causing a roll-a-coaster type ride as the aircraft increases and then decreases pitch, based on pilot input and autothrottle thrust control.

A/T ARM solenoid, N1 and speed button. The N1 and speed button illuminate when either is in active mode. In the image, the A/T is armed; however, the speed option is not selected (the annunciator is extinguished). This enables thrust to be controlled manually

Autothrottle Non-Normal Operations (Arm Mode)

The primary function that the A/T ARM mode is to provide minimum speed protection. A crew can ARM the throttle but not have it linked to a speed. To configure the autothrottle in ARM mode, the A/T toggle solenoid on the MCP is set to ARM, but the SPEED button is not selected (the annunciator is not illuminated).

Scenario - speed button not selected during approach

Some flight crews prefer during an approach, to arm the autothrottle, but not have the speed option engaged (speed annunciator extinguished).

By doing this during a non-precision approach, it enables a Go-Around to be executed more expediently and with less workload (the pilot flying only has to push the TO/GA buttons on the thrust lever and the autothrottle will engage).

If the approach proceeds smoothly and a Go-Around is not required, the crew will prior to landing, disengage the A/T solenoid switch on the MCP by either manually 'throwing' the toggle or pressing the A/T buttons located on the thrust levers. Although favoured by some flight crews, this practice is not authorized by all airlines, with some company policies expressly forbidding the ARM A/T technique.

The recommendation by Boeing in the B737 Flight Crew Training Manual (FCTM) states:

‘The A/T ARM mode is not normally recommended because its function can be confusing. The primary feature the A/T ARM mode provides is minimum speed protection in the event the airplane slows to minimum maneuvering speed. Other features normally associated with the A/T, such as gust protection, are not provided’. (When the A/T is armed and the speed button option not selected).

Autothrottle Speed Protection and Vref in Windy, Gusty and Turbulent Conditions

To provide sufficient wind and gust protection, when using the autothrottle during an approach in windy conditions, the command speed should set to the correct wind additive based on wind speed, direction and gusts (between Vref+5 and Vref +20).

The use of an additive creates a safety envelope that takes into account potential changes in wind speed and minimises the chance of the autothrottle commanding a speed that falls below Vref. Remember, that as wind speed varies the autothrottle will command a thrust based on the speed.

During turbulence, the autothrottle will maintain a thrust that is higher than necessary (an average) to maintain command speed (Vref).

Important Points:

When the autothrottle is not engaged, or the speed option on the MCP deselected, minimum speed protection is lost.
Always add a wind additive to Vref based on wind strength and gusts. Doing so provides speed protection when the autothrottle is engaged.

Refer to Crosswind Landings Part 2 for additional information on Vref.

A/T disengage button on throttle thrust lever. This is an OEM throttle from a B737-300 series. The button is identical to that used in the NG with the exception that the handles are usually white and not grey in colour. Depressing this button will disengage the autothrottle and disconnect the A/T solenoid switch on the MCP

Manual Override - Engaging the Clutch Assembly

Occasionally, for any number of reasons, the flight crew may need to override the autothrottle.

The Boeing autothrottle system is fitted with a clutch assembly that enables the flight crew to either advance or retard the thrust levers whilst the autothrottle is engaged. By moving the thrust levers, the clutch assembly is engaged and the autothrottle goes offline whilst the levers are moved.

The clutch is there to enable the autothrottle to be manually overridden, such as in an emergency or for immediate thrust control.

ProSim737 does not (as at 2018) support manual autothrottle override.

Simulation Nuances

The above information primarily discusses the systems that operate in the real aircraft. Whether these systems are functional in a simulation, depends on the avionics suite used (Sim Avionics, Project Magenta, etc).

For example, the autothrottle may not maintain the speed selected in the MCP during particular circumstances (for example, turns in high winds). If this occurred in the real world, a crew would manually override the autothrottle. However, if the avionics suite does not have this functionality, then the next best option is to either:

(i) Disengage the autothrottle and manually alter thrust; or,

(ii) Deselect the speed annunciator on the MCP.

Deselecting the speed annunciator will cause the throttle automation to be disengaged; however, the autothrottle will remain in the armed mode. The second option is a good way to overcome this shortfall of not having manual override. By deselecting the speed option, the thrust levers can be jiggled forward or aft to adjust the airspeed. When the speed has been rectified by manual input, the autothrottle can be engaged again by depressing the speed button.

It's important if the autothrottle is not engaged, or is in the ARM mode, that the crew maintains vigilance on the airspeed of the aircraft. There have been several incidents in the real world whereby crews have failed to observe airspeed changes.

Manual Flying (no automation engaged)

The benefit of flying with the autothrottle and autopilot not engaged is the ease that the aircraft can be maneuvered. The crew sets the appropriate %N1 that produces the correct amount of thrust to maintain whatever airspeed is desired; gone are the thrust surges as the autothrottle attempts to maintain airspeed.

Granted, it does take considerable time and patience to become competent at flying manually in a variety of conditions, but the overall enjoyment increases three-fold.

Company Policies

Airline policies often dictate how a flight crew will fly an aircraft, and while some policies are expedient, more often than not they are based on economics (cost savings) for the company in question.

Policies vary concerning autothrottle use. For example, Ryanair has a policy to disconnect the autothrottle and autopilot simultaneously, as does Kenya Airways. Air New Zealand and QANTAS have a similar policy, however, define an altitude that disconnection must occur at or before. If an airline doesn't have a policy, then it's at the discretion of the flight crew who should follow Boeing's recommendation in the FCTM.

Confusion and Second Guessing - Vref with A/T Engaged or Disengaged

There is considerable confusion and second guessing when it comes to determining the Vref to select dependent on whether the autothrottle is engaged or disconnected at landing. To simplify,

If the autothrottle is going to be disconnected before reaching the threshold, the command speed should be adjusted to take into account winds and gusts (as discussed above and refer to Crosswind Landings Part 2). It's vital to monitor airspeed when the autothrottle is not engaged as during the approach the speed can decay close to stall speed.
If the autothrottle is to remain engaged during the landing (as in an autoland precision approach), the command speed should be set to Vref +5. This provides speed protection by keeping the engine thrust at a level that is commensurate with the Vref command speed. If wind and gust indicate a higher additive speed, then this should be added to Vref.

Refer to Wind Correction Function (WIND CORR) for information on how to use the Wind Correction function in the CDU.

Final Call

There is little argument that the use of the autothrottle is a major benefit to reduce task loading; however, as with other automated systems, the benefit can come at a cost, which has lead several airlines to introduce company policies prohibiting the use of autothrottle without the use of the autopilot; pitch coupling, excessive vertical speed, and incorrect thrust can lead to hard landings and possible nose wheel collapse, unwanted ground effec t, or a crash into terrain.

Ultimately, the decision to use or not use the autothrottle and autopilot as a coupled system is at the discretion of the pilot in command, and depends upon the experience of the crew flying the aircraft, the environmental conditions, and airline company policy. However, the recommendation made by Boeing preclude autothrottle use without the autopilot being engaged.

Disclaimer

The content in this post has been proof read for accuracy; however, explaining procedures that are convoluted and often subjective, can be challenging. Occasionally errors occur. If you observe an error, please contact me so it can be rectified.

Acronyms and Glossary

A/P – Autopilot (CMD A CMD B).
A/T – Autothrottle.
AFDS – Autopilot Flight Director System .
Command Speed - In relation to the Autothrottle, Command Speed is Vref +5 knots.
FCTM – Flight Crew Training Manual (Boeing Corporation).
FMA – Flight Mode Annunciator.
Manual Flight – Full manual flying. A/T and A/P not engaged.
MCP – Mode Control Panel.
Minimal Speed Protection – Function of the A/T when engaged. The A/T has a reversion mode which will activate according to the condition causing the reversion (placard limit). (For example, flaps, gear, etc).
Pitch Coupling – The coupling of A/T thrust to the pitch of the aircraft. A/T thrust increases/decreases as aircraft pitch and attitude changes. Pitch coupling occurs when the A/P is not engaged, but the A/T is enabled.
Selected/Designated Speed – The speed that is set in the speed window of the MCP.
Take Off/Go Around (TO/GA) – Takeoff Go-around command mode. This mode is engaged during takeoff roll by depressing one of two buttons beneath the throttle levers.
Vref – Landing reference speed.

Updated and Amended 04 July 2019

August 04, 2014

Boeing 737-800 Takeoff Procedure (simplified)

August 04, 2014/ Flaps 2 Approach

One aspect novice virtual pilots find difficult to grasp is the correct method of flying the aircraft, especially the takeoff, climb and transition to cruise.

The sheer volume of information available on the Internet often results in information overload and it’s understandable that many become bewildered as the boundaries between fact and fiction blur. Add to this that many articles on the Internet have not been peer reviewed, and you have a recipe set for disaster!

In this article, I will instruct on the basic procedures used to takeoff, climb, and transition to cruise. I’ll also provide some insight into how flight crews fly the aircraft, and discuss some of the more important concepts that should be known.

I will not discuss before and after takeoff checklists, the overhead, how to determine aircraft weights, or how to use of the Control Display Unit (CDU). I will assume all essential elements of pre-flight have been completed. Also, the following procedures assume both engines are operational. I will not be addressing engine-out procedures.

Please take note that some procedures are dependent upon what software is used in the Flight Management System (1). Furthermore, the display of specific items, such as the speed reference indicators on the Primary Flight Display (PFD), will only be displayed if the CDU is correctly set-up prior to takeoff.

I have attempted to try and simplify the procedure as much as possible. However, the automated systems that can be used on the Boeing aircraft are complicated, can be used fully or in part, and can easily generate confusion. Add to this that some procedures are different between an automated and manual takeoff, and some procedures are dictated by airline policy.

It is a challenge to simplify what in the first place is convoluted and technical.

I have set out the content in three parts:

Section One refers to a simplified generic procedure for takeoff (numerical sequence 1–20). Below each numerical number are important points (summarized as dot points). Although this section primarily refers to hand flying the aircraft, some automation concepts are discussed.
Section Two discusses takeoff procedures using automation.
Section Three provides additional information concerning important points mentioned in Section One and Two.

To minimise wordiness in this article, I have for the most part, used acronyms and footnotes. Refer to the end of the article for a list of acronyms and their meaning.

Peer Review

The information in this article has been peer reviewed by 737 Captain and First Officer.

Automation and Variability

The Boeing 737-800 can be flown with, without, or partly with automation. The combinations that can be used, how they work, and more importantly when to use them, can fill a book. Indeed, there is a book (two books) – they’re called the Flight Crew Operations Manual and the Flight Crew Training Manual.

The first point to take on board is that there is no absolute correct method for takeoff and climb. Certainly, there are specific tasks that need to be completed, however, there is an envelope of variability allowed. This variability may relate to how a particular flight crew flies the aircraft, environmental considerations (ice, rain, wind, noise abatement, obstacles, etc.), flight training, or a specific airline policy.

Whenever variability is injected into a subject, individuals who think in absolutes - black and white - will have difficulty. If you are the kind of person who likes to know exactly what to do at a particular time, then I suggest you find a technique that fits with your liking and personality.

SECTION ONE: Takeoff Guideline (1-20)

The following procedures assume essential elements of pre-flight have been completed (for example, correct set-up of CDU).

1. Using the Mode Control Panel (MCP), dial into the altitude window an appropriate target altitude, for example 13,000 feet.

2. Command speed is set in the MCP speed window. The speed is set to V2. V2 is determined by calculations made by the Flight Management Computer (FMC) based on aircraft weight, environmental conditions and several other parameters.

Important Points:

V2 is the minimum takeoff safety speed and provides at least 30° bank capability with takeoff flaps set. This speed provides a safe envelope to fly with one engine (if an engine failure occurs).
You can fly either +15 or +20 knots (maximum +25 knots) above the V2 command speed. This is done for a number of reasons: to lower or increase pitch due to the aircraft's weight, or to take into account other environmental variables (this assumes both engines operational), or it is dictated by airline policy.
A white-coloured airspeed bug is displayed at V2 +15/20 on the speed tape (part of the PFD). V2+15 knots provides 40° bank capability with takeoff flaps set. The bug is a visual aid to indicate the correct climb-out speed (bug is discussed later on).

3. Toggle both Flight Director (FD) switches to the O’ position (pilot flying side first).

4. Set flaps 5 and using the electric trim switch on the yoke, trim the aircraft to the correct trim figure for takeoff. The trim figure is shown on the CDU (for example, 5.5 degrees) and is calculated dependent upon aircraft weight with passengers and fuel. Normally the trim figure will place the trim tabs somewhere within the green band on the throttle quadrant. Takeoff should not occur if the trim tabs are outside of the green band.

5. Arm the autothrottle (A/T) by moving the toggle on the MCP to ARM. This may differ between airlines (when to arm the A/T) Consult the FCOM & FCTM.

6. Release the parking brake and manually advance the thrust levers to around 40%N1. %N1 can be airline specific with some airlines recommending 60%N1. Consult the FCOM & FCTM.

7. Monitor the EGT on the EICAS and when there is a decrease in EGT and the throttles are stabilised, either:

Advance the thrust levers to takeoff thrust (if hand flying); or,
Press one or both TOGA buttons if wishing the autothrottle system to be selected. If the autothrottle system has been selected for takeoff, both thrust levers will automatically begin to advance to the correct %N1 output calculated by the Flight Management System.

Interesting Point:

After takeoff configuration is complete, and with the parking brake in the OFF position, some flight crews quickly advance and retard the thrust levers. The purpose being to check for errors in the takeoff configuration. An error will trigger the audible configuration horn when the thrust levers are advanced.
Become conversant with derates. Using a particular derate is normal practice, but in particular will help control over-pitching and high vertical speeds, which are a common occurrence when the aircraft is light (minimal fuel load, passengers and/or cargo).

Important Points:

You do not have to stop the aircraft on the runway prior to initiating 40%N1. A rolling takeoff procedure is often recommended, as this expedites the takeoff (uses less runway length) and reduces the risk of engine damage from a foreign object being ingested into the engine (engine surge/stall due to a tailwind or crosswind).
When the thrust has reached 40%N1, wait for it to stabilise (roughly 2-3 seconds). Look at the N1 thrust arcs and the EGT gauge (on the EICAS display). Both N1 arcs must be stable and the EGT values decreasing slightly. In the real aircraft, the EGT should reduce between 10C-20C after N1 has stabilised at 40%. If the engines are NOT allowed to stabilise, prior to advancing the thrust levers, the takeoff distance can be adversely affected.
There is considerable confusion around when to actually press the TOGA buttons. As stated, %40N1 is common, but some airline procedures indicate 60%N1, while others recommend a staged approach – meaning, initially advance the thrust levers to 40%N1, allow the thrust to stabilise, and then advance the thrust levers to 70-80%N1 and press TOGA.
Do not push the thrust levers forward of the target %N1 - let the autothrottle do its job (otherwise you will not know if the autothrottle system has failed). See Point 10 concerning hand placement.
Ensure the autothrottle has reached the target %N1 by 60 knots ground speed. If not, execute a Rejected Takeoff (RTO).
Unless you select a different mode, the TOGA command mode that was engaged at takeoff (assuming you used the autothrottle system), will remain engaged until you reach the assigned altitude indicated on the MCP.
Selecting N1 on the MCP does not disengage TOGA mode. If you want to disengage TOGA mode, the Flight Director switches must be toggled to the OFF position, or another vertical mode selected.
In some simulators that use ProSim737 software (Version 2 & 3), you will notice that when throttle arm is displayed on the PFD, the throttle will retard slightly (%N1). This is NOT normal and is a ProSim737 software glitch. The issue is easily resolved by moving the thrust levers forward slightly. This glitch does not appear to cause other problems.

8. Maintain slight forward pressure on the control column to aid in tyre adhesion to the runway. Focus on the runway approximately three-quarters in front of the aircraft. This will assist you to maintain visual awareness and to keep the aircraft on the centreline. Use rudder and aileron input to control any crosswind.

9. During the initial takeoff roll, the pilot flying should place their hand on the throttle levers in readiness for a rejected takeoff (RTO). The pilot not flying should place his hand behind the throttle levers. Hand placement facilitates the least physical movement should an RTO be required.

10. The pilot not flying will call out 80 Knots Pilot flying should slowly release the pressure on the control column so that it is in the neutral position. Soon after the aircraft will pass through the V1 speed (this speed is displayed on the speed tape). Takeoff is mandatory at V1, and Rejected Takeoff (RTO) is now not possible. The pilot flying, to reaffirm this decision, should remove his or her hands from the throttles; thereby, reinforcing the must fly rule. (see important points below).

11. At Vr (rotation), pilot not flying calls Rotate. Pilot flying slowly and purposely initiates a smooth continuous rotation at a rate of no more than 2 to 3 degrees per second to an initial target pitch attitude of 8-10 degrees (15 degrees maximum).

Important Points:

Normal takeoff attitude for the 737-800 is between 8 and 10 degrees. This provides 20 inches of tail clearance at flaps 1 and 5. Tail contact will occur at 11 degrees of pitch (if the aircraft is still on or close to the ground).
Takeoff at a low thrust setting (low excess energy, low weight, etc) will result in a lower initial pitch attitude target to achieve the desired climb speed.
The correct takeoff attitude is achieved in approximately 3 to 4 seconds after rotation (depending on airplane weight and thrust setting).
Point 10 (above) discusses hand placement during the takeoff roll. Another method used differentiates responsibility between the Captain and First Officer. The Captain as Pilot in Command (PIC) will always have control of the thrust levers, while the pilot flying (First Officer) will concentrate solely on the takeoff with both hands on the control column. Removal of the hand after V1 is a standard operational procedure (SOP). This assumes that the First Officer will be pilot flying.

12. Following takeoff, continue to raise the aircraft’s nose smoothly at a rate of no more than 2 to 3 degrees per second toward 15 degrees pitch attitude. The Flight Director (FD) cues (pitch command bars) will probably indicate approximately 15 degrees.

Be aware that the cues provided by the Flight Director may on occasion be spurious; therefore, learn to see through the cues to the actual aircraft horizon line.

The Flight Director pitch command is NOT used during rotation.

13. At this stage, you most likely will need to trim the aircraft to maintain minimum back pressure (neutral stick) on the control column. The 737 aircraft is usually trimmed to enable flight with no pressure on the control column. It is quite normal, following rotation, to trim down a tad to achieve neutral loading on the control column. Do not trim during the actual rotation of the aircraft.

14. When positive rate has been achieved, and double checked against both the actual speed the aircraft is flying at (see speed tape on PFD), and the vertical speed indicator, the pilot flying will call Gear Up and the pilot not flying will raise the gear to minimize drag and allow air speed to increase. The pilot not flying will also announce Gear Is Up when the gear has been retracted successfully (green lights on the MIP have extinguished).

15. The Flight Director will command a pitch to maintain an airspeed of V2 +15/20. Follow the Flight Director cues (pitch command bar), or target a specific vertical speed. The vertical speed will differ widely when following the FD cues as it depends on weight, fuel, derates, etc. If not using the FD, try to maintain a target vertical speed (V/S) of ~2500 feet per minute.

Important Points:

V2 +15/20 is the optimum climb speed with takeoff flaps (flaps 5). It results in maximum altitude gain in the shortest distance from when the aircraft left the runway.
If following rotation the FD cues appear to be incorrect, or the pitch appears to be too great, ignore the FD and follow vertical speed guidance.
Bear in mind that vertical speed has a direct relationship to aircraft weight - if aircraft weight is low to moderate, use reduced takeoff thrust (derates) or Assumed Temperature Method to achieve a recommended vertical speed.
If LNAV and VNAV were selected on the MCP prior to takeoff, LNAV will provide FD inputs at 50 feet and VNAV will engage at 400 feet.
When VNAV is engaged, the speed of the aircraft will be automatically updated on the speed tape and the speed window on the MCP will become blank.
If LNAV and VNAV have not been selected prior to takeoff, it is common practice to manually select a roll mode (LNAV) at 400 feet. VNAV is usually selected after flaps UP.
If LNAV and VNAV has been selected prior to takeoff. LNAV is advisory. VNAV will automatically update the autothrottle system. The aircraft will not fly the LNAV course or the VNAV vertical profile until the autopilot is selected (CMD) on the MCP.

16. Follow and fly the cues indicated by the FD (automation), or maintain a command speed at V2 +15/20 (hand flying) until you reach Acceleration Height (AH). AH is often stipulated by company policy and is usually between 1000-1500 feet ASL. AH can be changed in the CDU.

17. At or when passing through Acceleration Height (~1500 Feet RA), a number of tasks may need to be completed. These tasks will cause the PFD display to change.

The nose of the aircraft is to be lowered (pitch decreased). This will increase airspeed and lower vertical speed. A rough estimate to target is half the vertical speed used at takeoff.
The flaps should be retracted as per the Flaps Retraction Schedule. If noise abatement is necessary, flaps retraction may occur at Thrust Reduction Height.
Retract flaps as per the Flaps Retraction Schedule. Retract each degree of flaps as the aircraft's speed passes through the next flap increment détente. The flaps increment détente is displayed in green on the PFD speed tape. For example, as the aircraft passes through the flaps 1 designation you would select flaps 5 to flaps 1. Then, when the airspeed passes through the flaps UP position you would select flaps 1 to flaps UP. You do not want to exceed the flaps limit speed. (See Interesting Points (second dot point) regarding the Speed Trend Vector).
Do not retract flaps unless the aircraft is accelerating, and the airspeed is at, or greater than V2 +15/20 - this ensures the speed is within the manoeuvre margin allowing for over-bank protection. Do not retract flaps below 1000 feet RA.
When flaps retraction commences, the airspeed bug will disappear from the speed tape on the PFD.
If hand flying (VNAV not selected), at Acceleration Height set the speed in the speed window of the MCP to a speed that corresponds to the flaps UP speed. The flaps UP speed can be found displayed on the speed tape on the PFD. This is often referred to as Bugging Up.
Some flight crews when reaching Acceleration Height call Level Change, Set Top Bug. This ensures that TOGA speed is disengaged (by selecting another mode).
If VNAV has been selected prior takeoff, the flaps UP speed will be automatically populated and displayed on the speed tape on the PFD. However, the speed will not be displayed in the MCP speed window (the window will be blank).

18. When the aircraft flies through the flaps UP speed, and after the flaps have been fully retracted, the desired climb speed is dialed into the speed window of the MCP (If VNAV is not selected). If VNAV has been selected, the climb speed will be automatically populated and displayed on the PFD (as will the cruise speed when the aircraft reaches cruise altitude).

Important Points:

If VNAV is selected, the speed window in the MCP is blank. However, if VNAV is not selected the speed window is open.
If automation and the autothrottle system (TOGA) is not being used, and you are hand flying the aircraft, Press N1 on the MCP (if desired) at Acceleration Height and follow FD cues to flaps UP speed.
When N1 is selected, the autothrottle will control the speed of the aircraft to the N1 limit set by the FMS. Selecting N1 ensures the aircraft has maximum power (climb thrust) in case of a single engine failure.
If the autothrottle system (TOGA) has been used during takeoff, N1 is automatically selected (by the FMS) at Thrust Reduction Altitude (usually ~1500 feet RA). There is no need to press the N1 button on the MCP.
N1 mode doesn’t control the aircraft’s speed - it controls thrust. The autothrottle will set the maximum N1 thrust (power). The aircraft’s speed is controlled by the pitch attitude.
Selecting N1 on the MCP does not provide any form of speed protection.
Acceleration Height can be changed in the CDU.
The auotpilot should NOT be engaged prior to flaps UP. This is often stipulated by airline policy,

19. The aircraft is usually flown at a speed no faster than 250 KIAS to 10,000 feet. At 10,000 feet, speed is usually increased to 270 KIAS. Environmental factors and/or ATC may result in differing speeds being set.

At this stage, the aircraft can be hand flown with or without VNAV and/or the autothrottle. You can either:

Continue to hand fly the aircraft to altitude. Appropriate climb and cruise speeds will need to be dialed into the MCP; or,
Select a suitable pitch and roll mode (LVL CHG, V/S, LNAV & VNAV) and engage the autopilot or select CWS. If a pitch and roll mode is selected and the autopilot not selected, the FD will provide visual cues.

20. At 10,000 feet, dial 270 KIAS into the MCP speed window and then at 12,000 feet dial in 290 KIAS. Follow the Flight Director cues, or if the FD is not being used, maintain roughly 2000-2500 fpm vertical speed. At cruise altitude, transition to level flight and select on the MCP speed window 290-310 KIAS or whatever the optimum speed is (see CDU).

Interesting Points:

Many pilots had fly the aircraft to 10,000 feet before engaging the autopilot. To enhance situational awareness, it is common practice, if hand flying, to have LNAV and VNAV selected. This enables the pilot to follow the navigation cues displayed on the PFD.
Located on the speed tape on the PFD, is a green coloured line called a Speed Trend Vector (STV). The Speed Trend Vector will display an upwards, neutral or downwards facing arrow. During climb-out, the Speed Trend Vector arrow can be used to determine how long it will take for the aircraft, at the current thrust setting, to reach the speed that the arrow is pointing at (usually around 10 seconds). Therefore, when the upward arrow reaches the flaps indicator, the aircraft will pass through this flaps détente in approximately 10 seconds. The Speed Trend Vector can be used to help know when to initiate retraction of the flaps.

Summary

The above procedures are general. Specific airline policy for a particular airline may indicate otherwise. Likewise, there is considerable latitude to how the aircraft is flown, whether it be without automation selected, or with part or full automation selected.

It is very easy to become confused during the takeoff phase - especially in relation to automation, V speeds, acceleration heights, and how and when to change from hand flying to automation The takeoff phase occurs quickly, there is a lot to do, and quite a bit to remember - there is little time to consult a manual or cheat sheet.

SECTION TWO: Takeoff Guideline (LNAV, VNAV & autopilot selected prior to takeoff)

Although I have mentioned some of the VNAV procedures in the above discussion, I though it pertinent to include this section which will address a takeoff with LNAV and VNAV selected (points 1-10 below). This information relates to FMS software U10.8A.

Important Point:

The aircraft requires information from the FMS when automation (LNAV & VNAV) is used. For the takeoff to be successful, the PERF INIT and navigation data must be inputted into the CDU.

The following 10 points outline a VNAV selected takeoff:

Select from the CDU a Standard Instrument Departure (SID) and press the illuminated annunciator (EXEC) on the CDU.
Verify the Flight Director switches are selected to the ON.
ARM LNAV and VNAV on the MCP (press the LNAV & VNAV buttons on the MCP).
ARM the Autopilot (press CMD A/B) and set the Command Speed in the speed window of the MCP to V2 (The V2 speed can be found in the takeoff page of the CDU).
Takeoff (as discussed earlier).
VNAV will engage at 400 feet and the Flight Director will command V2 +15/20. The appropriate bugs on the PFD speed tape will be populated automatically. The speed should always be crosschecked against the actual speed that the aircraft is flying and the white bug on the speed tape.
At Acceleration Height (between ~1000-1500 feet RA or as indicated in the CDU) the Flight Director will command a speed 10 knots above the FLAPS UP speed.
Lower the aircraft’s nose and follow the FD cues (command pitch bars).
Commence FLAPS retraction and follow the Flaps Retraction Schedule (Point 18 above).
As the FLAPS retract into the UP position the Flight Director will command 250 knots.
Select CMD A/B (autopilot) or fly to 10,000 feet or cruise altitude and select autopilot.

SECTION THREE: Additional Information - Summarised Important Points

Understanding %N1

To understand the various levels of automation it is important to have a relative understanding of %N1.

N1 is a measurement in percent (%) of the maximum RPM of an engine, where maximum RPM is certified at the rated power output for the engine (most simple explanation). Therefore, 100%N1 is maximum thrust, while 0%N1 is no thrust. (%)N1 will be at a percentage commensurate with the settings that have been inputted to the CDU (aircraft weight, fuel, derates, etc).

Important Points:

The autothrottle logic when TOGA selected controls the aircraft’s thrust (%N1). The aircraft’s speed is controlled by pitch (attitude).
To clarify what automated system is controlling the aircraft, always refer to the Flight Mode Annunciations (FMA) in the PFD (Refer to Table 1 for a quick overview of annunciations displayed during the takeoff).

Common Practice - What to Select For Takeoff

It is not the purpose of this article to rewrite the FCOM or FCTM. Needless to say, there are several combinations, that can be selected at varying stages of flight. All are at the discretion of the pilot flying, or are stipulated as part of airline policy.

After Acceleration Height has been reached, the aircraft’s nose lowered to increase speed, and the flaps retracted, it is common practice to use LVL CHG, V/S, or LNAV and VNAV, and either hand fly the aircraft, select CWS, or select the autopilot (usually at or above 3000 feet, but certainly after flaps UP) and fly to cruise altitude.

If the takeoff does not use LNAV and VNAV (not selected on the MCP) LNAV can be selected at, or after 50 feet RA and VNAV can be selected at, or after 400 feet RA. After either of these two modes have been selected, the Flight Director cues will automatically update to reflect the data that has been inputted into the CDU.

Theoretically, a crew can hand fly the aircraft following the FD cues at V2 +15/20 to the altitude set in the MCP. However, there will be no speed protection, and if the pitch cues recommended by the FD are not followed, then the airspeed may be either below or above the optimal setting or safety envelope. Selecting an automation mode (not V/S) is what engages the speed protection (speed protection will be discussed shortly).

In the above scenario (assuming the aircraft is being hand flown), unless another vertical mode is selected, the aircraft will remain in TOGA command mode (thrust controlled by N1) until the altitude set in the MCP is reached. To deselect (cancel) TOGA as the command mode, another mode such as LVL CHG, VNAV or V/S will need to be selected. Altitude Hold (ALT HOLD) also deselects TOGA as does engaging the autopilot.

Flight crews typically hand fly the aircraft until the flaps are retracted (flaps UP) and the aircraft is in clean configuration. A command mode is then selected to continue the climb to cruise altitude. CWS or the autopilot may or may not be engaged.

Important Point:

It is important to understand what controls the various command modes. For example, LVL CHG is controlled by N1 and pitch. In this mode, the autothrottle will use full thrust, and the speed will be controlled by pitch.

**TABLE 1:** N1 MCP annunciation and FMA displays for common time events during takeoff and climb

**TABLE 2:** Throttle command modes for common time events during takeoff and climb. The flight crew can manually override the autothrottle logic by advancing or retarding the thrust levers by hand. This can only be done at certain phases of flight. Throttle online means that the crew can override the autothrottle logic, while Throttle offline means that the logic cannot be overridden

Speed Protection

One of the advantages when using the automated systems is the level of speed protection that some of the systems provide. Speed protection means that the autothrottle logic will not allow the aircraft’s speed to be degraded to a value, by which the aircraft can stall or be below maneuvering speed.

Speed protection is not active with every automated system. Whether speed protection is active depends upon the U version of the FMS software in use, the automation mode selected, and whether the flaps are extended or fully retracted.

The following examples indicate whether speed protection is available;

Level Change (LVL CHG): When you select LVL CHG, the speed window will open allowing you enter a desired speed. LVL CHG is speed protected, meaning that the aircraft's speed will not increase beyond the speed inputted into the MCP. This is because LVL CHG is controlled by N1 (thrust) while the aircraft’s speed is controlled by pitch.

VNAV: VNAV has active speed protection for the leading edge devices (U10.8A and above) . This is why VNAV can be selected on the ground.

Vertical Speed (V/S): V/S provides no speed protection. This is because V/S holds a set vertical speed. In V/S, if you are not vigilant, you can easily encounter an overspeed or under speed situation.

N1: Selecting N1 by pressing the N1 button on the MCP (without any other mode selected) does not provide speed protection. Using the N1 mode, only ensures maximum thrust is generated.

Important Points:

Speed protection is armed only for some levels of automation.
It is imperative that you observe the Flight Mode Annunciator (FMA) to check that the aircraft is flying the mode intended.

Always Think Ahead

As stated, the takeoff phase happens quickly, especially if the aircraft’s weight is light (cargo, passengers and fuel).

Soon after rotation (Vr), the aircraft will be at Acceleration Height and beyond… It’s important to remain vigilant and know what’s happening, and to think one step ahead of the automated system that is controlling the aircraft. You do not want the automation to get ahead of you and hear yourself thinking what’s it doing now.

Aircraft Weight

Although briefly discussed earlier, I would like to enlarge upon how the weight of the aircraft can have an affect on takeoff and climb. An aircraft’s weight is altered by the volume of fuel on board, the number of passengers, and the amount of cargo carried in the holds.

In some respects, a heavily laden aircraft, although requiring higher thrust settings and longer runway length, will be more stable than the same aircraft at a lighter weight. A lightly laden aircraft will use less runway and, unless thrust settings are managed accordingly, will be prone to an excessive rate of climb (high vertical speed and high pitch angle). This can lead to tail strike and uncomfortably high rates of ascent.

To manage this, flight crews often limit the takeoff thrust by using one of several means. Typically, a thrust derate is used with either CLB 1 or CLB 2 set in the CDU, or an assumed temperature thrust reduction is used. Selecting either option will cause a longer takeoff roll (less thrust) and delay the rotation point (Vr), however, the climb-out will be less aggressive and more manageable.

Final Call

Reiterating, the above guidelines are generalist only. Flight crews use varying methods to fly the aircraft, and often the method used will be chosen based on company policy, crew experience, aircraft weight, and other environmental factors, such as runway length, weather and winds.

Additional Information:

Future Articles

Time permitting, other articles will be published dealing with: descent, initial approach, and landing (ILS, VNAV, Circle to Land and RNAV).

Disclaimer

The content in this post has been proof read for accuracy, however, explaining procedures that are convoluted, technical, and somewhat subjective can be challenging. Errors on occasion present themselves. If you observe an error (not a particular airline policy), please contact me so it can rectified.

Footnotes

(1): For example, there are different protocols between FMC U10.6 and FMC U10.8 (especially when engaging VNAV and LNAV prior to takeoff). I have purposely not addressed these differences because they can become very confusing (another article will do this). As at writing (2020), ProSim737 uses U10.8A.

download article

Acronyms and Glossary

AFDS – Autopilot Flight Director System
AH - Acceleration Height. The altitude above sea level that aircraft’s nose is lowered to gain speed for flap retraction. AH is usually 1000 or 1500 feet and is defined by company policy. In the US acceleration height is usually 800 feet RA
CDU, FMC & FMS – Control Display Unit / Flight Management Computer (term often used interchangeably). The visual part of the Flight Management System (FMS) that enables input of variables. FMS is the system and software (U10.8A). FMC is the actual computer, and the CDU is the hardware.
CLB 1/2 – Climb power
Command Mode – The mode of automation that controls thrust
EICAS – Engine Indicating and Crew Alerting System
F/D – Flight Director (Flight Director cues/crosshairs)
FMA – Flight Mode Annunciation located upper portion of Primary Flight Display (PFD)
KIAS – Knots Indicated Air Speed
LNAV – Lateral Navigation
LVL CHG – Level Change Command Mode
MCP – Mode Control Panel
N1 & N2 – N1 and N2 are the rotation speeds of the engine sections expressed as a percentage of a nominal value. ... The first spool is the low pressure compressor (LP), that is N1 and the second spool is the high pressure compressor (HP), that is N2. The shafts of the engine are not connected and they operate separately. Often written N1 or %N1.
RTO – Rejected Take Off
T/O Power – Takeoff power
Throttle On & Offline – Indicates whether the throttle is being controlled by the A/T system
TOGA – To Go Around Command Mode
TRA - Thrust Reduction Altitude. The altitude that the engines reduce in power to increase engine longevity. The height is usually 1500 feet; however, the altitude can be altered in CDU
V/S – Vertical Speed Command Mode
V1 – is the Go/No go speed. You must fly after reaching V1 as a rejected take off (RTO) will not stop the aircraft before the runway ends
V2 – Takeoff safety speed. The speed at which the aircraft can safely takeoff with one engine inoperative (Engine Out safe climb speed)
VNAV – Vertical Navigation
Vr – Rotation Speed. This is the speed at which the pilot should begin pulling back on the control column to achieve a nose up pitch rate
Vr +15/20 – Rotation speed plus additional knots (defined by company policy)

Updated April 2021.
Updates March 2024.

July 18, 2014

OEM 737-800 Lights Test Toggle Switch - Wired and Installed to MIP

July 18, 2014/ Flaps 2 Approach

OEM Lights Test Switch (before cleaning...) One switch comprising several switches

The lights test is an often misunderstood but simple procedure. The light test is carried out by the crew before each flight to determine if all the annunciators are operating correctly (illuminating). The crew will toggle the switch upward to lights test followed by a routine scan of each annunciator on the overhead, center pedestal and instrument panel. An inoperative light may preclude take off.

The lights test switch is a three-way switch which can be placed (and locked) in one of three positions; it is not a momentary switch. Toggling the switch upwards (lights test) illuminates all annunciators located in the MIP, forward and aft overhead and fire suppression panel (wheel well annunciator may not illuminate), while the central position (BRT) provides the brightest illumination for the annunciators (normal operation). Toggling the switch downwards activates the DIM function dimming the brightness by roughly half that observed when the toggle is in BRT mode.

Depending upon which manufacturer’s Main Instrument Panel (MIP) you are using, the toggle switch may not function this way. For example, Flight Deck Solutions (FDS) provide a three-way momentary toggle which is not the correct style of switch. You should not have to hold the toggle to light test as you make your pre-flight scan. The real toggle switch in the Boeing 737 aircraft is not a momentary switch.

Anatomy of the Toggle Switch

The OEM Light Test switch may appear to be a ‘glorified’ toggle switch with an aviation-sized price tag; however, there is a difference and a reason for this high price tag.

The switch although relatively simple in output, encompasses 18 (6+6+6) high amperage individual switches assigned to three terminals located on the rear of the switch. Each terminal can be used to connect to a particular aircraft system, and then to each other. This allows the toggle switch to turn on or off multiple aircraft systems during the light test.

The purpose of these multi-terminals is to allow the toggle switch to cater towards the high amperage flow of several dozen annunciators being turned on at any one time during the lights test, in addition to generators and other aircraft systems that are not simulated in Flight Simulator. In this way, the switch can share the amperage load that the annunciators draw when activated during the light test.

The switch can control the annunciators (korrys) for the MIP, forward overhead, aft overhead, fire suppression panel and any number of modules located in the center pedestal.

OEM Lights Test switch. The appearance of the OEM switch is not dissimilar to a normal toggle switch; however, the functionality is different in that there are a number of terminals on the rear of the switch to allow multi-system connection

Terminals, Interfacing and Connection

To determine the correct terminals to be used for the light test is no different to a normal toggle-style switch.

First, ascertain which of the six terminals correlate to the switch movement (toggle up, center and down). The three unused terminals are used to connect with other systems in the real aircraft (not used in Flight Simulator).

To determine the correct terminals for wiring, a multimeter is set to conductivity (beep) mode. Place one of the two multimeter prongs on a terminal and then place the other prong on the earth (common) terminal. Gently move the toggle. If you have the correct terminal for the position of the toggle, the multimeter will beep indicating an open circuit. The toggle switch does not require a power source, but power is required to illuminate the annunciators during the lights test.

For an overview of how to use a multimeter see this post - Flight Deck Builders Toolbox - Multimeter.

Daisy Chaining and Systems

Any annunciator can be connected to the light test function, and considering the number of annunciators that the light test function interrogates, it is apparent that you will soon have several dozen wires that need to be accommodated.

Rather than think of individual annunciators, it is easier to relate a group of like-minded components as a system. As such, depending upon your simulator set-up, you may have the MIP annunciators as one system, the overhead annunciators as another and the fire suppression panel and modules mounted in the center pedestal as yet another. If these components are daisy chained together (1+1+11+1+1=connection), only one power wire will be required to be connected at the end of the array. This minimises the amount of wire required and makes connection easier with the toggle switch.

Two Methods to Connect to the Switch

There are two ways to wire the switch; either through the flight avionics software (software-based solution), or as a stand-alone mechanical system. There is no particular benefit to either system. The software solution triggers the Lights Test by opening the circuit on the I/O cards that are attached to the computer, while, the mechanical system replicates how it is done in the real Boring aircraft.

Switch in-line (software connection using ProSim737)

The on/off terminal of the toggle switch is connected to a Leo Bodnar card or other suitable card (I use a Flight Deck Solutions System card), and the card’s USB cable connected to the main computer. Once the card is connected, the avionics suite software (ProSim737) will automatically register the card with to allow configuration. Depending upon the type of card used, registration of the inputs and outputs for the card may first need to be registered in Windows (if using Windows 7 type into the search bar joystick and select calibration).

To configure the toggle switch in ProSim737, open the configuration/switches tab and scroll downward until you find the lights test function. Open the tab beside the name; select the appropriate interface card (Leo Bodnar card) from the drop down menu and save the configuration.

ProSim737 will automatically scan the interface cards that are installed, and if there is a card that has a power requirement, such as a Phidget 0/16/16 card (used to convert OEM annunciators, modules and panels), the software will make a connection enabling the lights test to function.

Considering the connection is accomplished within the ProSim737 software, it stands to reason the lights test will only operate when ProSim737 is open.

To illuminate the annunciators when the switch is thrown, a 28 volt power supply will need to be connected to the annunciators either separately or in a daisy chain array.

OEM aviation relay mounted in center pedestal

Stand-alone (mechanical connection)

The second method, which is the way it is done in the real aircraft, is to use an OEM 50 amp 6 pull/6 throw relay device.

Depending upon the type of relay device used (there are several types), it may be possible to connect up to three systems to the one relay.

Lights Test Busbar

Although the Lights Test switch has the capacity to connect several systems to the switch itself, it would be unmanageable to attempt to connect each panel to the lights test switch.

To solve this issue a centrally-placed aviation-grade relay has been used in association with a busbar.

A benefit of using an OEM relay and busbar is that the relay acts as a central point for all wires to attach. The wires from the various systems (panels, korrys, etc) attach to the busbar which in turn connects to the various posts on the relay.

The relay will then open or close the relay enabling power to reach the annunciators (via the busbar) when the switch is positioned to Lights Test.

The stand-alone system will enable the lights test to be carried out without ProSim737 being open.

Although the relay is not large (size of a small entree plate), it can be problematic finding a suitable area in which to mount the relay where it is out of the way. A good location is to mount the relay inside the pedestal bay either directly to the platform floor or to a wooden flat board that is screwed to the lower section of the center pedestal.

Using the DIM Functionality (toggle thrown downwards)

This post has only discussed the lights test. The DIM switch is used to dim the OEM annunciators (korrys) for night work.

Another article explains the DIM functionality.

**Diagram 1:** basic overview to how the oem lights test toggle is connected

**diagram 2:** flow schematic between oem light test toggle and annunciators

April 20, 2014

Using Interface Cards and Canon Plugs To Convert OEM B737 Parts

April 20, 2014/ Flaps 2 Approach

an example of oem wiring and a canon plug

There is little argument that real aircraft parts add a level of realism and immersion to the flight simulator experience. Furthermore, real parts (Original Equipment Manufacture/OEM) are built to last and if converted correctly will provide many years of trouble-free operation and enjoyment.

For the uninitiated, conversion of OEM parts can appear problematic. Where does one begin to convert an aircraft part for simulator use?

This post will attempt to explain the basics behind converting and connecting an OEM module via an interface card and Canon plug to Flight Simulator using ProSim737. Additionally, it will introduce and provide a general overview of Phidget Manager 21 (PM-21) software.

Please note, I am not an expert on electronics. My background is Earth Science (geology) which is far removed from electronics... Like others, I have learnt how things are done by 'trial and error' and listening to those more knowledgeable than myself in this field.

OEM Parts - Modules and Panels

The first thing you will notice about an OEM part (module/panel) is the build, feel and appearance is much better than a reproduction part. It is at this stage you will be thinking ‘I don’t really want to destroy the part by opening it and rewiring everything’. The good news is that, while some parts certainly do need rewiring, many do not.

Fortunately, the process to convert many OEM components is similar. Granted the pin-outs and wiring are different between units, but the methodology used to determine the pin-outs is identical. It’s a matter of replicating your methodology with each part.

Canon Plugs - The Interface to a Wiring Maze

If you look inside a OEM panel you will be surprised at the multitude of multicolored wires that connect to various relays, switches, solenoids and circuitry. Moreover you will be very impressed with the neatness and integrity of the wiring harness and as mentioned earlier, you will be loath to destroy the craftsmanship employed.

Twin Canon plugs belonging to a OEM 737 AFDS. The plug on the right is OEM while the left is bespoke

In the real aircraft, a module is connected to the aircraft’s wiring harness by a Canon plug which is a plug with any number of pins; each pin corresponding to particular function. A Canon plug can be locked in place with the clockwise turn of the locking cap providing a solid yet removeable connection.

The benefit of Canon plugs, amongst others, is that they provide an easy and solid connection to the module’s internal wiring. Many individuals remove these plugs, pull apart the module and gut the wiring starting afresh. While this certainly is possible, why do it when all that is required is to ascertain the pin-outs of the Canon plug to connect to the wiring inside the module. I doubt many of us, with the exception of a professional electrical craftsman, have the ability to duplicate the quality of workmanship seen in an OEM module.

Unfortunately, it is common place to find modules that are sold without the corresponding male or female side of the plug. In this case the correct male or female plug must be bought separately, an existing plug converted, or a new plug fabricated. If you have the opportunity to use a Canon plug, always try to use it before cutting the plug from the unit.

Determining Pin outs - The Value of a Good Multimeter

The crux of converting an OEM module is to understand the functionality of the module in question. The best place to begin learning how a module operates is the latest FCOM. OEM modules are made for real aircraft and as such often have functions that may not be incorporated into flight simulator. After arming yourself with 'operator knowledge', the next step is to decipher the often cryptic maze of pins in the Canon plug. Once this is understood, the conversion is relatively straightforward with the addition of an interface card and power supply (if needed).

oem Canon plugs showing the snake-like pattern of pin location and numbering. This module uses two Canon plugs marked J1 and J2

The pins of a Canon plug will provide at the minimum: functionality for the part, an earth (common) and a pin (s) dedicated to power. Traditionally, all modules have used incandescent bulbs for backlighting which is powered by 5 Volts. Depending upon functionality, some modules require different voltages with 28 Volts being the norm.

It’s important to be able to decipher which pin does what to ensure correct functionality within Flight Simulator. This involves logical thinking and little bit of trial and error. It is a high probability that not all the pins in the Canon plug will be used or needed in Flight Simulator. Remember, that in a real aircraft there are multiple systems and some wires and pins will connect with these 'unneeded' systems.

If you carefully study the pin layout in a Canon plug you will note it is not random – there is a definite order in how the pins are presented. You will note that in all probability some pins are numbered, but not all. The numbers move sequentially so the pin beside the pin marked ‘5’ will either be pin ‘4’or pin ‘3’. The snake-like pattern printed on the inside of the plug is there for good reason - it acts as map guiding you from the highest number to the lowest.

By far the easiest way to determine pin-outs for functionality and power, if you do not have a wiring schematic, is to use a multimeter set to continuity mode (beep mode).

How to read continuity with a multimeter: Flight Deck Builders Toolbox: Multimeter .

Phidget card (one of several types). Phidgets are a proven way to convert many OEM components; the 0/0/4, 0/16/16, analogue and servo cards been mainstays.

Which Interface Card

Most parts require an interface card of some type to allow communication between the part and flight simulator. There are several cards that, depending upon the part’s functionality, can be used: Leo Bodnar joystick cards and PoKeys cards are commonly used while Phidget cards have been the mainstay for quite a few years. Flight Deck Solutions also produce some excellent system cards while Polulu is another manufacturer.

Which interface card is used will depend on the functionality of the module. A simple on/off switch or a rotary knob can be interfaced using a PoKeys, Leo Bodnar Joystick or another similar 'button-type' card. If you have a lever that needs calibration then a potentiometer will be needed. The Leo Bodnar card is an excellent choice and will automatically register the potentiometer’s movement as an axis when the card is activated in Windows. A light indication (korry), or a more complicated module may require a card such as Phidget 0/16/16 or 0/0/4 card. Throttle automation and motor activation will need additional cards such as a Phidget Advanced Servo card or Polulu card.

Phidget Cards

Phidget cards, or Phidgets, have been around for a considerable time and have been the mainstay for enthusiasts wishing to control robots, cars, airplanes and the like. Phidgets produce several cards; however, the core cards used in flight simulation are the Phidget advanced servo cards, 0/16/16, 0/0/8 and 0/0/4 cards. To read more about Phidget cards, navigate to the the Phidget website and enter the card type into the search bar.

What Does the Interface Card Do?

The interface card is placed between the computer and the OEM module and the wires from the Canon plug are fed directly to the card (power wires usually do not connect with the card). The card provides you with three things: an input, an output and a USB connection to the computer (or a powered hub that is then connected to the computer). Once connected, the card acts as an interface which converts an inbound analogue signal (For example, the upwards or downwards ‘throw’ of a switch) to an outgoing digital signal. For every analogue input there will be a corresponding digital output.

An interface card requires software/logic which either comes with the card (embedded) or is downloaded from the developer’s website. Some cards utilize Windows and the process of plugging the card into the computer will initialize the card allowing the embedded software of the card to be viewed from in Windows. The software is found by opening the joystick controllers menu - type ‘joy’ into the search tab of the computer to be directed to this joystick wizard.

An example of a card that has embedded software and comes pre-calibrated is the Leo Bodnar Joystick card. The 'Leo' card uses the joystick controller menu in Windows to allow access to the card logic. Other cards such as Polulu require calibration and programming in their own software and without calibration and programming will appear unresponsive when first connected to a computer. Phidget cards utilize their own software (Phidget Manager 21) downloadable from the Phidgets website.

If using multiple cards of the same make and type, each card will be assigned a dedicated number allowing you to know which card controls what module.

To connect a function (for example a switch) to the Interface card you run the wire from the Canon plug/terminal to the input terminal on the card. This process is replicated for each function of the module, bearing in mind that some functions on the Captain and First Officer side may be duplicated. If this is the case, the wires from the module are connected into the same input terminal on the card.

If power is required to operate the module's function or for backlighting of the panel, then a wire from the power supply will need to be connected to the correct pin in the Canon plug of the OEM module. The usual method is to connect power from the power supply to a solid high amperage terminal block and then to the OEM module. Power is not normally connected directly to an interface card, unless the card has this particular capability.

The connection of the wires to the card and connection of the card to the computer provides the link to enable the various inputs and outputs to be read either by standalone software, Windows, or directly in ProSim737.

Phidget Manager 21 User Interface. Each serial number is specific to an individual card that is allocated when configuring the output in ProSim737

Phidget Manager 21 (PM-21) - The Bare-shell Basics

PM-21 is the replacement for the older styled Phidget’s Library.

Phidget Manager 21 (PM-21) software when installed to your computer generates a list indicating which Phidget cards are currently connected to the computer. Each connected Phidget card can be opened individually from this list. Selecting a card will open a sub-window providing set-up information and the inputs and outputs for the selected Phidget card.

There is also a testing area to check the functionality (inputs & outputs) of the module in addition to several other specialist features.

It is a little difficult to explain, but when this screen is open you can as in the above example, manipulate the switch up or downwards and a corresponding tick (check mark) will be seen in the input. PM-21 will then assign this item (switch) to a dedicated output number specific only to this card. The output number is what is used when configuring the device in ProSim737.

If converting an indicator (light) or mechanically-produced sound, the software can be used to determine if the indicator has been wired correctly. Selecting the input section and placing a tick (check) into the appropriate box will cause the indicator to illuminate or the sound to become audible.

PM-21 UI for Phidget 0/16/16 card that controls fire suppression panel. Moving a switch on the hardware will show a corresponding tick in the input section. The output section can be used to test the hardware to ensure the function is working correctly

It is important to remember that the Phidgets 21 Manager can only read installed cards if ProSim737 is closed (as of ProSim737 Version 1:34). If the ProSim737 main menu is open, PM-21 cannot obtain the necessary information to read the card correctly.

Configuring the Interface Card in ProSim737

Once the wires from the module have been connected to the inputs of the interface card and inspected (in PM-21, Windows, or whatever software) for correct connection, the output from the interface card must be configured in ProSim737.

Before proceeding further, it is important to determine if the cards you are using are being read by ProSim737. Open the main ProSim737 menu and select configuration/drivers and confirm that each box corresponding to the card type installed has been checked/ticked. After this has been verified, the main ProSim737 screen will indicate which cards ProSim737 is reading. This is a handy way to know if your interface cards are connecting correctly to your computer and are being correctly read by ProSim737.

The process to configure an output is addressed in the ProSim737 manual. Therefore, the following is an overview.

To configure an output:

Select the appropriate tab in the configuration menu (configuration/switches, configuration/indicators, etc.) that corresponds to the function of the module (i.e. light test switch)
Scroll down through the list to find the correct function (i.e. light test switch)
Move the switch on the module noting the input/output variables at the top of the computer screen
From the drop down box beside the function, select the correct interface card type and serial number. (Another method is to press A located beside the function. This will automatically select the last known position of the switch and automatically assign it).
Beside the interface card drop down menu, there is another drop down menu. Select this menu and select the correct digital output (variable shown on the screen when the switch was moved)

A similar method can be used for indicators.

Once this is done, close and reopen the ProSim737 main menu. The function should now be registered in ProSim737. Although this process sounds rather convoluted, once done a few times it becomes second nature.

Conclusion

This is a very simple introduction to the conversion of OEM parts using the Canon plug system and the use of interface cards, in particular Phidget cards and the use of Phidget Manager 21 software.

In general, PoKeys, Leo Bodnar joystick cards and Phidget cards (type 0/16/16 and 0/0/4) will cover the interfacing of many functions used in real aircraft modules. However, not every part is as easy as a switch to convert. Depending upon the complexity of the module, there may be multiple pin outs that need to be deciphered, additional logic needed, and the requirement to use multiple or single interface and/or relay cards before the part will successfully connect with Flight Simulator.

Acronyms and Glossary

Canon Plug – A plug made by Canon that allows a secure link between wiring systems. The plug incorporates any number of pins, each pin corresponding to a particular functionality. Many Boeing modules incorporate one, two, three or four Canon plugs depending upon the degree of sophistication in the module.
Module or Panel – Boeing parts are often called modules or panels (I use both words interchangeably)
OEM – Original Aircraft Manufacture (real aviation part).
Phidget Manager 21 (PM-21) – Software supplied by Phidgets that provides the logic behind the various Phidget interface cards.

December 04, 2013

B737 Throttle Quadrant - Parking Brake Mechanism

December 04, 2013/ Flaps 2 Approach

oem 737-500 parking brake lever and light

This post we will briefly discuss the conversion of the parking brake mechanism, and a video will demonstrate the solenoid engaging to move the lever within the mechanism. The function of the parking brake is self-explanatory.

Parking Brake - Solenoid Auto Release

The parking brake can be engaged or disengaged by either engaging (lifting) or disengaging (pushing down) the park lever, or by depressing the toe brakes located on the rudder pedals.

In the real aircraft, mechanical linkages and a cam disengage the parking brake. A solenoid has been installed to replicate this in the simulator.

Interfacing with Flight Simulator

To use the solenoid, a relay card (on/off) and standard toggle-style switch is used. The relay card is mounted in the Trial Interface Master Module (IMM) and connection from the throttle to the IMM is via a straight-through custom VGA cable. Any brand relay card will do this job.

Red Bulb

The red light is illuminated by a 28 Volt bayonet-style light bulb. The bulb can be downgraded to 12 Volts; however, the illumination produced will not be as bright as if a 28 volt bulb was used.

Spring, Solenoid and Toggle

The operation of the park brake lever revolves around four items:

A long rod that connects from the lower section of the park lever to the toggle switch;
A standard on/off toggle-style switch;
A solenoid;
A high tensile spring; and,
A relay card.

parking brake Solenoid attached to port side firewall of throttle unit

When the park brake lever is pushed down or pulled up a corresponding movement of the long rod occurs. Connected to the lower part of the rod is a standard-style toggle switch and a spring. The spring is attached to the base of the throttle unit. Movement of the rod causes the toggle to either be switched on or off (up/down), while the spring provides the tension for the automatic movement of the park lever to occur when the solenoid is energized (the lever is pulled downwards to the disengaged position). A relay card is connected to the solenoid to control the timing that the solenoid receives power.

Toe Brakes Activation of Park Brake

As in the real aircraft, the parking brake can be released by the pilot depressing the toe brakes.

There are two methods commonly used to connect the toe brakes to the release of the park brake lever and parking brakes.

The first (and easiest) method uses a Phidget 0/0/4 (1014_1) relay card and logic from within FSX or the avionics software (ProSim737), while the second method is a standalone closed system that can be implemented using a double-throw relay and a momentary switch; the switch being specific to the park brake. For simplicity, I have incorporated the first method into the simulator as ProSim737 and FSX already provide a software solution to release the parking brakes.

Below is a short video showing how the parking brake mechanism operates.

737 throttle parking brake mechanism

In the next and final post regarding the throttle conversion, we will inspect the movement of the thrust levers during engagement of the Autothrottle (A/T) and discuss some of the teething issues with the throttle conversion.

Update

on 2017-06-26 06:40 by FLAPS 2 APPROACH

In June 2015, this mechanism was replaced with a more reliable system that replicates how the system operates in the real Boeing aircraft. The system now in place is purely mechanical and does not rely on ProSim-AR for operation (other than registration of the movement of the parking brake lever).

The new system has been documented here: Throttle Quadrant Rebuild: Parking Brake Mechanism Replacement, Improvement and Operation .

October 09, 2013

B737 Center Pedestal Completed and Installed - Flight Testing Begins

October 09, 2013/ Flaps 2 Approach

oem 737-500 center pedestal and custom panels. The center pedestal from the 500 series is very similar to that of the next generation

After spending the best part of two weeks wiring the various panels into the center pedestal I am now pleased with the result.

The center pedestal is from a Boeing 737-500 and is made from fibreglass. The earlier series two-bay pedestals were made from aluminium. The three bay pedestal allows much more room inside the pedestal to mount interface cards and house the wiring for the various panels (modules).

However, as with every positive there often is a drawback. In this case there are two drawbacks. The first is a few spare holes must be covered with OEM blanking plates, and the second is the three bay pedestal is considerably wider than a two bay pedestal. Whilst climbing into the flight deck is easy at the moment, once a shell is fitted, J-Rails will need to be fitted to the seats to allow easy access.

Space

Taking advantage of the extra internal space of a three bay, I have constructed a small shelf that fits inside the lower section. The shelf is nothing fancy - a piece of wood that fits securely between the two sides of the pedestal. Attached to this shelf are bus bars, a Leo Bodnar interface card and a FDS interface card. A Belkin powered hub also sits on the shelf. The power supply for the hub resides beneath the platform to the rear ( for easy access).

The bus bars provide power for the various OEM panels and backlighting, while the Leo Bodnar card provides the interface functionality for the two ACP units. The FDS card is required for operation of the three FDS navigation and communication radios I am currently using.

My aim was to minimise cabling from the pedestal forward to the throttle unit. The reason for this is the throttle is motorized and moving parts and USB cables do not work well together. I have two cables that go forward of the pedestal to the computer; one USB cable from the powered Belkin hub and the other the cable required to connect the CP Flight panels. Both cables have been carefully routed along the inner side of the throttle quadrant so as to not snag on moving internal parts.

Pedestal Colour

The original pedestal was painted Boeing grey which is the correct colour for a B737-500. The unit was repainted Boeing white to bring it into line with the colour of the B737-800 NG pedestal.

oem 737-500 center pedestal illuminated by 5 volt incandescent bulbs

Backlighting

The backlighting for the throttle quadrant and center pedestal is turned on or off by the panel knob located on the center pedestal. Power is from a dedicated S-150 5 Volt power supply rated to 30 amps.

“On the Seventh day, GOD created backlighting and the backlighting was said to be good”.

The light plates are mostly aircraft bulbs; however, a few of the panels, such as the phone and EVAC panel, are LEDS and operate on 28 Volts rather than the standard 5 Volts.

Size Does Matter...

It's important when you install the wiring for backlighting that you use the correct gauge (thickness) wire. Failure to do this will result in a voltage drop (leakage), the wire becoming warm to touch, and the bulbs not glowing at their full intensity. Further, if you use a very long wire from the power supply you will also notice voltage drop; a larger than normal wire (thickness) will solve this problem. There is no need to go overboard and for average distances (+-5 meters) standard automotive or a tad thicker wiring is more than suitable to cater to the amp draw from incandescent bulbs.

To determine the amperage draw, you will need to determine how many amps the bulbs are using. This can be problematic if you're unsure of exactly how many light plates you have. There are several online calculators that can be googled to help you figure out the amperage draw. Google "calculation to determine wire thickness for amps".

At the moment, I am not using a dimmer to control the backlighting, although a dimmer maybe installed at a later date.

Minor Problem - Earth Issue

A small problem which took considerable time to solve was an earth issue. The problem manifested by arcing occurring and the backlighting dimming. I attempted to solve the problem by adding an earth wire from the pedestal to the aluminium flooring; however, the issue persisted. The issue eventually was tracked down to an OEM radar panel which was "earthing" out on the aluminum DZUS rails via the DZUS fasteners. To solve the problem, I sealed the two metal surfaces with tape.

Panels

The panels I am currently using are a mixture of Flight Deck Solutions (FDS), CP Flight, 500 and Next Generation:

NAV 1/2 (FDS)
M-COM (FDS)
ADF 1/2 (CP Flight) - replaced with FDS
Light Panel (OEM)
Radar Panel (OEM)
EVAC Panel (OEM)
Phone Panel (OEM)
Rudder Trim Panel (CP Flight) - replacd with OEM
ATC Transducer Radio (OEM)
ACP Panel x 2 (OEM)
Fire Suppression Panel (OEM)

In time a ACARS printer will be added and some of the non NG style panels (namely the ACP panels) will be replaced with OEM NG style ACP panels. The OEM panels installed are fully operational and have been converted to be used with Flight Simulator and ProSim737. I will discuss the conversion of the panels, in particular the Fire Suppression Panel, in separate journal posts.

The more observant readers will note that I am missing a few of the "obvious" panels, namely the cargo fire door panel and stab trim panel. Whilst reproduction units are readily available, I'm loathe to purchase them preferring to wait; eventually I'll source OEM panels. Rome was not built in a day.

Panel Types

If you inspect any number of photographs, it will become apparent that not all aircraft have exactly the same type or number of panels installed to the pedestal. Obviously, there are the minimum requirements as established by the relevant safety board; however, after this has been satisfied it's at the discretion of the airline to what they order and install (and are willing to pay for...). It's not uncommon to find pedestals with new and old style panels, incandescent and LED backlighting, colour differences and panels located in different positions.

oem 737-500 center pedestal telephone. although not next generation it completes the pedestal

Telephone Assembly

Purists will note that the telephone is not an NG style telephone and microphone. I have keep the original B737-500 series telephone and microphone as the pedestal looks a little bare without them attached.

If at some stage I find a NG communications assembly I'll switch them, but for the time being it will stay as it is.

Flight Testing - Replication

The throttle quadrant and center pedestal are more or less finished. The next few weeks will be spent testing the unit, it's functionality, and how well it meshes with ProSim737 in various scenarios. This process always takes an inordinate amount of time as there are many scenarios to examine, test and then replicate.

Replication is very important as, oddly, sometimes a function will work most times; however, will not work in certain circumstances. It's important to find these gremlins and fix them before moving onto the next level.

KIS - Keep It Simple

Although everything is relatively simple in design (OEM part connects to interface card then to ProSim737 software), once you begin to layer functions that are dependent on other functions working correctly, complexity can develop. It's important to note that the simulator is using over a dozen interface and relay cards, most mounted within the Interface Master Module (IMM) and wired to an assortment of OEM parts configured to operate with ProSim737's avionics suite.

September 28, 2013

B737-500 Throttle Conversion to NG Style - Overview

September 28, 2013/ Flaps 2 Approach

This is the second throttle unit I’ve owned and based on experience, there are many changes that have been implemented that are different to the earlier unit.

The throttle quadrant is a relatively complicated piece of kit. To do it justice, rather than write about everything in one very long post, I’ve decided to divide the posts into sections.

This is the first post that will deal with the general attributes of the throttle unit, interface cards used and touch on the automation and motorization of the unit. Further detailed posts will address individual functionality, conversion and troubleshooting.

Historical Perspective and Conversion

The throttle quadrant and center pedestal were removed from an Alaskan Air Boeing 737-500 airframe. I purchased the unit directly from the teardown yard in Arizona (via a finder).

The conversion to full automation and motorization was not done by myself, but by a good friend of mine who is well versed in the intricacies of the B737 and in the various methods used to install automation to a throttle unit. I am very fortunate to be friends with this individual as in addition to being an excellent craftsman with a though understanding of electronics; he is also a retired Boeing 737 Training Captain.

forward bulkhead of oem 737-500 throttle

New Design

The new throttle unit has been converted to Flight Simulator use based on a new design. The interface cards, rather than being mounted on the forward bulkhead have been mounted within the Interface Master Module (IMM) which is separate to the actual throttle unit. The DC motors required for throttle and speed brake motorization are mounted forward of the throttle unit (in the traditional location).

Connection from the throttle to the IMM is via specially-adapted VGA cables and D-Sub plugs. This keeps the unit clean of unsightly wiring and interface cards. it also keeps loose cables and wires to a bare minimum on the outside of, and inside the unit; automation and motorization means that there are now moving parts and it’s important to separate delicate cards and wiring away from mechanically moving parts

This is in stark contrast to my first throttle that had the interface cards mounted directly on the forward bulkhead and within the unit.

In addition, micro buttons have been used in some circumstances to counter the traditional method of using potentiometers to control calibration of the speed brake, flaps and throttles.

Center Pedestal - Cabling and Wiring

The three-bay center pedestal, mounted directly behind the throttle unit, has a number of cables and connections required for individual panel operation. Rather than have these cables weave through the mechanism of the throttle (remember this is an automated throttle and there is considerable movement inside the unit), I’ve opened a hole into the platform directly under the pedestal.

Any wiring or cabling is routed through this hole into a piece of round flexible conduit tubing (it’s actually the hose from a disused washing machine). The cables, after making their way to the front of the platform, then connect either to the computer or the Interface Master Module.

The use of flexible tubing is not to be underestimated as any cabling must be protected to avoid the chance of snagging on the under-floor yoke and rudder mechanisms which are continually moving.

Interface Cards

Conversion of any OEM part to operate within Flight Simulator requires interface cards. The following cards are used to convert analogue outputs to digital inputs for the throttle unit. The cards also provide functionality for the fire panel, landing gear, yaw dampener, flaps and brake pressure gauges on the Main Instrument Panel (MIP). All cards are mounted on the separate Interface Master Module (IMM).

Alpha Quadrant Motor Controller card A - TQ automation & logic CMD A channel
Alpha Quadrant Motor Controller card B - TQ automation & logic CMD B channel
Phidget High Current AC Motor Controller card – Provides two channels for trim wheel speeds and trim wheel movement
Phidget Motor Controller Advanced Servo card – Provides the interface or bridging between the Alpha Quadrant cards and flight avionics and CMD A
Phidget Motor Controller Advanced Servo card - Provides the interface or bridging between the Alpha Quadrant cards and flight avionics and CMD B
Phidget Motor Controller Advanced Servo card – Movement of flaps gauge
Phidget Motor Controller Advanced Servo card – Movement of trim indicator tabs
Leo Bodnar BU0836 A Joystick Controller card – Controls all switches & buttons on TQ
PoKeys 55 card - Flaps (buttons)
Phidget 0/0/8 relay card – Speed brake, auto throttle relays CMD B, fire panels, trim wheel revolution speed on CMD B
Belkin 7 input USB 6.5 amp powered mini hub (2) – TQ

Phidget Cards

Phidgets cards provide the necessary interface between the throttle and flight simulator. I believe that Phidget cards are probably one of the more reliable cards on the market that can be used to directly interface OEM parts to flight simulator.

In addition to the two Alpha Quadrant cards mentioned above, a Phidget High Current AC Controller card acts as a "bridge" to allow communication between the Alpha Quadrant cards and the avionics suite (in this case ProSim737). This card also provides the connectivity to allow the trim wheels to spin when CMD A or B is selected on the Main Control Panel (MCP).

Trim Tab Indicators and Throttle Buttons

To control the movement of the two trim tab indicators, a Phidget Motor Controller Advanced Servo card is used to control the output to two, two-stage DC motors. These motors, which are normally used to power water pumps, control the variable speed of the trim indicators and the revolution of the trim wheels. The speed which the indicator moves is reliant on the user setting within the “trim section” in the configuration page of the flight avionics software.

A Leo Bodnar BU0836A Joystick Controller card is used to control all switches and buttons on the throttle unit, while a Phidget 0/0/8 relay card is used to turn logic on and off that controls the actions of the speed brake.

white colour of next generation thrust levers is unmistakable

Automation

Essentially, automation is the use of CMD A or CMD B (auto pilot) to control the N1 outputs of the throttle, and motorization is the moving of the throttle levers in unison with N1 output.

Automation is achieved by the use of two main motor controller cards (Alpha Quadrant cards); one for CMD A and another card for CMD B. Each card operates separately to each other and is dependent upon whether you have CMD A or CMD B selected on the Main Control Panel (MCP).

The Alpha Quadrant cards provide the logic from which the automation of the throttle unit operates.

Being able to program each card allows replication of real aircraft logic and systems. Whenever possible, these systems and their logic have been faithfully reproduced..

Main Controller Cards (thanks NASA)

The controller card I have used is not a Phidget card but a specialist card often used in robotics (Alpha Quadrant card). The software to program the card has been independently developed by a software engineer and does not utilize Phidgets.

The technology used in the controller card is very similar to that utilized by NASA to control their robotic landers used in the space industry. The technology is also used to control robots used in the car industry and in other mass production streams. One of the benefits of the card is that it utilizes a software chip that can be easily replaced, upgraded or changed.

CMD A/B Auto Pilot - Two Independent Systems

Most throttle units only use one motor controller card which controls either CMD A or CMD B; whichever auto pilot you select is controlled by the same card.

In the real aircraft to provide for redundancy, each auto pilot system is separate. This redundancy has been duplicated by using two Alpha Quadrant controller cards, rather than a single card. Each controller card has been independently programmed and wired to operate on a separate system. Therefore, although only one CMD is operational at any one time, a completely separate second system is available if CMD is selected.

Synchronized or Independent Motorization

Synchronization refers to whether the two throttle thrust levers, based upon separate engine N1 outputs, move in unison with each other (together) or move independently.

In the real aircraft, on earlier airframes, the levers were synchronized; however, the NG has a computer-operated fuel control system which can minutely adjust the N1 of each engine. This fuel management can be observed in a real aircraft whereby each throttle lever creeps forward or aft independent of the other lever.

Programming flight simulator to read separate N1 outputs for each engine and then extrapolating the data to allow two motors to move the throttle levers independently is possible; however, the outputs are often inaccurate. This inaccuracy can be seen on reproduction throttle units that show huge gap between lever one and lever two when automating N1 outputs.

I decided to maintain the older system and have both levers synchronized. If at some stage in the future I wish to change this, then it’s a matter of adding another motor to the front of the throttle bulkhead to power the second thrust lever.

Although the TQ is automated, manual override (moving the thrust levers by hand) is possible at any time as long as the override is within the constraints of the real aircraft logic and that provided by the flight avionics (ProSim737).

Motors

Four motors are used in the throttle unit.

Two electric motors are mounted forward of the bulkhead. These motors power the movement of the throttle levers and speed brake. Two DC pump motors are installed directly within the throttle unit and power the movement of the trim wheels and trim tab indicators.

A clutch system is also mounted to a solidly mounted frame on the forward bulkhead. The clutch system is used by the speed brake. The method of locomotion between clutch and thrust levers is a standard automobile style fan belt.

To allow both thrust levers to move in unison, a bar linking the lever which is motorized to the non-motorized lever was fabricated and attached to the main shaft of the motor.

The motors chosen were automobile electric window motors. These motors are powerful, provide excellent torque and were selected due to their reliability and ease of use.

Trim Wheel Spinning

The trim wheels can spin at two different speeds dependent upon whether the auto pilot is engaged or whether automation is turned off (manual flying). A Phidget High Current AC Controller card is used to interface the spinning of the trim wheels. The Phidget card has two channels and each channel can be programmed to a different revolution speed. The speed of the revolutions is controlled directly within the Phidget Advanced menu within the ProSim737 software.

The system was duplicated using a second Phidget card to ensure that both CMD A and CMD B operated identically.

In the real aircraft there are four different revolution speeds dependent upon the level of automation and the radio altitude above the ground. Although it is possible to program this logic into the Alpha Quadrant cards and bypass ProSim737 software, it was decided not to as the difference in two of the four speeds is marginal and probably unnoticeable. Further, the level of complexity increases somewhat programming four speeds.

Trim Wheel Braking

In the real aircraft, the trim wheels have an effective braking mechanism that stops the trim wheels from spinning down; basically it’s a brake. Testing of a military specification motor with brakes to stop wheel movement was done; however, the motors were too powerful and whilst the trim wheels did stop spinning, the noise and jolt of the brake activating was not acceptable.

Functionality and Configuration

The TQ has been converted to allow full functionality, meaning all functions operate as they do in the real Boeing aircraft. Speed brake, flaps, parking break, reverser levers, thrust levers, trim stabilizer runaway toggles, trim tab indications, TOGA and A/T buttons, horn cut out, fuel levers and two speed trim wheel spinning have been implemented.

These functions and the process of conversion and calibration (potentiometers and micro buttons) will be addressed in separate posts.

Configuration, if not directly to the Alpha Quadrant cards via an external software program is either directly through the avionics suite (ProSim737) and the Phidgets card software or through FSUIPC. Where possible, direct calibration and assignments via FSX have not been used.

Backlighting

The throttle unit's light plates, with the exception of the parking brake which is illuminated by a 28 Volt bulb, are back lit by 5 Volt aircraft bulbs. A dedicated S150 5 Volt 30 amp power supply is used to supply power to the bulbs.

Stab Trim T-Locker Toggles

The only function which is different from the real aircraft is the stab trim switch. The left hand toggle operates correctly for runaway trim; however, the right hand toggle has been configured that, if toggled to the down position, the trim wheels will stop spinning. The toggle is a basic on/off circuit and stops current going to the motors that move the trim wheels.

The reason for doing this is that I often fly at night and spinning trim wheels can be quite loud and annoying to non-flyers… The toggle provides a simple and easy way to turn them on or off at the flick of a switch.

Finding T-Lockers

Finding T-Locker toggles that are used in the NG series airframes is not easy. Reproduction units are available but they appear cheesy and rarely operate effectively as an OEM toggle. Earlier airframes used metal paddles (my earlier 300 series throttle used these type of trim switches) while the 400 series uses a different style again. Trim switches are usually removed and reinstalled into an aircraft; therefore, I was fortunate that the throttle unit I secured had the later model T-Lockers.

The switches are called T-Lockers as you must manually pull down the cover from each switch before pulling the toggle downwards. This is a safety feature to ensure that the toggles are not inadvertently pushed by the flight crew.

Thrust Handles - Colour

The colour of the throttle quadrant between the 737 aircraft variants leading towards the Next Generation series is similar, however, the colours are slightly different on the Next Generation throttle are different.

First, the thrust levers are not painted, but are cast in the actual colour. Despite this, older aircraft will exhibit UV fading causing the thrust levers to appear darker and yellower.

There is no distinct RAL colour, however, RAL 7047 is very close. The colour of the thrust levers is identical to the side walls, knobs and liners. The bac hex colour designation in BAC#705 (Federal STD 595B-36440). If you do not understand the various colour definition, search google for further information.

Importantly, it is almost impossible to find the correct colour codes as Boeing guards this information carefully to ensure it is not copied by rival aircraft manufacturers (why I am not sure).

More Pictures (less words...)

To see further pictures, navigate to the Image Gallery.

In this post we have discussed a general overview of the throttle quadrant and examined the automation and motorization. We also have looked at the interface cards used and studied the stab trim T-Lockers in more detail. In future posts we will examine the different parts of the throttle unit and learn how they were converted and calibrated to operate with Flight Simulator.

Click any mage to make it larger.

UPDATED 16 August 2022

June 01, 2013

B737-800 Cabin Phone System Panel - Center Pedestal

June 01, 2013/ Flaps 2 Approach

oem 737-800 cabin phone panel: Panel has three push buttons with backlighting and legends, and one toggle button

I recently acquired an avionics panel that is a little different to the norm. The panel was acquired from a company that was responsible for altering the on-board communication system for 50 Boeing 737-800 jetliners; the aircraft were being refitted with global communication equipment. The upside for me was that the panels were being decommissioned and were not required by the supplier.

Late model 737 Next Generation panels are uncommon to find; therefore, it is interesting to observe the differences between the older style classic panels regularly seen on e-bay, and a newer style panel.

The first thing that comes to mind, other than condition, is the lack of a rear box assembly on this panel. Instead of an aluminum box, the wiring is protected by a stainless bracket assembly. The wiring harness is also more refined and neater looking, while the backlighting, rather than using 5 Volt bulbs uses LED technology.

oem 737-800 cabin phone panel. note the crispness of the legend

LED Technology

Most people are familiar with the 5 volt incandescent bulbs used to illuminate the light panels in Boeing aircraft - the bulbs produce a soft yellow-orange hue. The colour temperature is in stark contrast to the white hue produced by LED technology.

I believe that airframes post 2006 utilise LED technology. Notwithstanding this, until older airframes are phased out, panel lighting will be a mixture of incandescent and LED lighting, or a combination thereof.

Matching Colour Hue

Attempting to match the backlighting colour hue, especially in the center pedestal and overhead panels has always been a challenge for flight deck builders, especially when using an assortment of older style OEM panels and panels made by differing companies (FDS, CP Flight, Open Cockpits, SimWorld, etc).

Wiring is very neat and the panel does not utilise the more commonly found aluminum box structure

What many virtual pilots forget, is that the only purpose for an airlines’ existence is to generate income and a profit for the company. Pilots on the other hand are more concerned with flying the aircraft.

There is very little thought as to whether a panel's backlighting is the same colour hue throughout all the panels. If and when a panel needs to be replaced, a technician’s only concern is getting a workable and certified instrument fitted into the aircraft as quickly as possible.

it is not unrealistic to have a few LED panels scattered amongst older bulb illuminated panels

Cabin Phone System Panel - What Works

Although there is no obvious use for this panel in the simulator, it is a good-looking panel that improves the overall aesthetics - it fills a 'gap' in the three-bay center pedestal. The buttons do function and when depressed change colour and provide different cautionss. Lifting the red cover and pushing the toggle to test causes the third button to illuminate 'smoke' in orange.

Although the panel has not been connected to an interface card, it is an easy process to connect a PoKeys or Leo Bodnar interface card to the Canon plug. ProSim737, nor Sim Avionics include functionality with this panel.

May 21, 2013

Purchase Guidelines - Avoid Being Disappointed

May 21, 2013/ Flaps 2 Approach

Based on feedback from my previous journal post, I decided to write a few lines dealing with what we, as simmers and virtual pilots, should expect from manufacturers and sellers. This post is more directed to those entering the hobby rather than experienced builders; those that have been in the 'game' long enough already know the 'do's and don'ts'.

In comparison to other more main-stream hobbies, flight simulation is relatively uncommon and specialized, and as with fishing, hiking, dog grooming and gardening, a plethora of companies have sprouted to supply the enthusiast with an assortment of “essential” add ons from panels and quadrants to books and magazines. Some manufacturers are large companies and others small “one man bands”.

'Caveat Emptor'

It is unfortunate, that even in our small community; all potential buyers must be conversant with the term 'Caveat Emptor' meaning in Latin 'Let the buyer beware'. Nobody is immune from the unscrupulous seller whose only want is to remove the hard-earned cash from your wallet or pocket book.

Since beginning the development of the B737 simulation two years ago, I have come into contact with many companies and individuals; some respectable, reliable and very honest, and others that live in the silt, that swirls around in the bottom of the barrel.

The small number of 'bottom crawlers' (without being offensive towards trilobites and other invertebrates) include not only those that sell reproduction parts, but also those that sell real secondhand aviation parts. One seller of real aviation parts lists and shows a picture of one item on his website, however, dispatches a different lower quality item.

Do you have recourse - NO! Once you have parted company with your money it is is gone forever......

Supply, Demand & Payment

One theme common to many suppliers is the time it takes to supply a customer with their product. This is especially evident when commissioning manufacturers to produce and supply hardware associated items such as yokes, panels and the like.

Suppliers always want their money up front and nearly always promise supply forthwith. Unfortunately, this rarely happens. Any number of excuses are promulgated: I’m busy, too many orders, lack of staff, waiting on parts, postal service delays, sickness – and the worst of all - no contact despite e-mails being received..

This is not to say that all companies and individuals selling flight simulation products have a poor reputation; this would be incorrect. There are many sellers that provide first rate service that cannot be bettered. It is unfortunate that all businesses do not subscribe to this philosophy.

Forums

It is an easy task to “troll” through one of several flight simulation forums and read the common threads evident in many of the posts published by disgruntled customers. If a common theme is duplicated in several threads, such as: delay, problems, glitches, bad communication or minimal contact, then why expect your experience to be different.

"past experience is a prime indicator to future performance".

Do Not Accept the Risk

I think anyone who has been involved with the industry for any length of time, has a horror story to tell.

It ceases to amaze me that many potential buyers that have read the threads on the forum and asked the correct questions, still proceed with an order and send full payment to an unscrupulous company or individual. It is almost as if they want the product so badly that they are happy to accept the risk! Then, after they have been let-down they post their story to a forum.

Unfortunately, this behavior only goes to strengthen the resolve of the suppliers that continue to behave in this manner. If you look at the supplier’s point of view, why should they improve their performance if there is any number of purchasers willing to order and pay for something in advance.

There is no incentive to change!

The only way the supplier will alter their behavior is if you, the customer, alter your behavior.

I'm not suggesting that a vendor will "run" with your money, but there have been instances of vendors suffering financial problems which culminated in them liquidating their business. If you have paid in full before production occurs, and a financial problem develops, then retrieving your money will probably be difficult.

Purchase Guidelines

Before any purchase:

Do your research. Know your product and know what you want for your set-up.
Ask others regarding their experiences with a company or individual.
Read the forums, learn to use the search functionality on each forum and contact members who use the same item you wish to purchase.
Ask on a forum whether a manufacturer is reliable, prompt and does good work. Building a flight deck is a detail thing; it’s not hammer and nails mentality. Why employ someone who is not into detail...
Try to only pay a deposit, despite being told otherwise.
You are the customer and you have a right (obligation) to ask anything you want of a manufacturer.
Secure an accurate time-line in writing to when an item will be supplied.
Ask about a return policy should you not be happy with the items purchased.
Finally, if the information you are told by several people is identical – then BELIEVE this information and don’t make the purchase.

Instead, contact the supplier and tell them your concerns and reasons why you will not be buying from them. Often when you do this, the supplier will alter their behavior to accommodate you. After all, they want your money!

Guidelines for purchasing real aviation parts

If an item looks a bargain it generally is not…..
Always check on return policy.
Only purchase from E-Bay from sellers with a solid positive feedback rating.
Pay via PayPal if possible as PayPal will provide buyer protection.
If the advert states "not checked, unsure if working or similar", then expect the item will be broken.
Assume nothing. Assumption is the "Mother" of all ClusterFucks". A "CluserFuck" is a military word meaning multiple problems (see definition a bottom of page).
Pay a little more and purchase ONLY from reputable, reliable and honest dealers.

Have I been caught before – of course! Will I get caught again – not likely, hopefully not....

Definitions

'CluserFuck' - Military term (mainly American) for an operation in which multiple things have gone wrong. Related to 'SNAFU' (Situation Normal, All Fucked Up") and 'FUBAR' (Fucked Up Beyond All Repair).

In radio communication or polite 'conversation (i.e. with a very senior officer with whom you have no prior experience) the term 'clusterfuck" will often be replaced by the NATO phonetic acronym 'Charlie Foxtrot'.

March 29, 2013

Reference Nav Data - CDU Functionality Explained

March 29, 2013/ Flaps 2 Approach

In past posts, I’ve documented some of the functionality of the Flight Management Computer (FMC) as displayed by the Central Control Unit (CDU). Following on with this theme, let’s look at four navigation data functions the FMC is capable of: Reference Nav Data, Nav Options, Nav Status and Nav Frequency Changes.

Before continuing, the FMC/CDU is controlled by the avionics suite you are using; whether it is ProSim737, Sim Avionics or whatever. Each avionics suite provides differing functionality; therefore, if something does not operate as indicated, it maybe a limiting factor of the avionics suite in use.

Note: This post follows standard terminology. lsk3R means line select key 3 right.

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A: REFERENCE NAV DATA

Occasionally, you will need to cross check information and the frequency of a specific navaid.

The Reference Nav Data display is part of the Nav Data page and can be assessed by the INDEX page:

INIT REF / INDEX / NAV DATA (lsk1R)

The screen will show three available options: Enter WPT Ident, Navaid Ident and Airport Ident.

Example: Type HB into the navaid Ident. Two pages will be displayed showing all the HB Idents from the navigation database. Selection of the appropriate navaid (HB) will present a further page displaying the following information: Navaid WPT, Airport and Ident code, Latitude, Longitude, Frequency, Elevation and magnetic variance.

NOTE: If you cannot identify the ident by name use the Longitude and Latitude coordinates.

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B: NAV OPTIONS & NAV STATUS

Following on from the Reference Nav Data page are: Nav Options and Nav Status.

Nav Options and Nav Status can be assessed two ways:

1: INIT REF/ INDEX / NAVDATA (lsk1R) / NAV OPTIONS (lsl6R)

2: PROG (progress) / NAV STATUS (lsk6R) (use when in flight)

Two consecutive pages are available: Nav Options and Nav Status. By default, Nav Status (page 2/2) is displayed. Use the PREV and NEXT PAGE keys to cycle between the two pages.

Nav Status - page 1/2

This page provides you with a list of the closest navaids including frequencies. It also indicates the currently set identifier and frequency for NAV 1 and NAV 2 (as set on the NAV 1/2 radio).

Nav Options - page 2/2

This page can be used to inhibit a particular waypoint or station. By inhibiting a navaid, it will not be able to be used by the CDU to calculate a navigation solution. By default all navaid types are activated. At crew discretion, two VOR and two DME stations can be inhibited. When you inhibit a navaid it will be removed from page 1/2 and not be visible in the Nav Status page list. The inhibited navaid will be reset when you reset the CDU.

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C: FREQUENCY CHANGE - ALTERING THE THE CDU

In usual practice, crew will alter the navigation, communication, ADF and transponder frequency on the actual panel located in the central pedestal. However, often you may need to cross check frequencies, dial in a third frequency for positional awareness, or use a frequency from an avionics module not present in the pedestal or that is malfunctioning.

The alter Nav Data screen can be assessed by:

MENU / MAINT (lsk6R) / COM/NAV (lsk3L)

This will display a page showing all idents and frequencies currently being used.

COM 1, COM 2, NAV 1, NAV 2, ADF 1, ADF 2 AND EXPR

To alter a frequency, type into the scratch pad the frequency of the navaid and upload to the appropriate line. To upload, select and press the key to the left or right of the nominated radio. Changing a frequency in the CDU will also cause a corresponding change in the frequency of the selected radio (in the center pedestal).

Flow Route

When you work through the above four functions of the CDU, you will note that the INDEX function is always available. This allows you to easily develop a flow route as you move between the various pages. Once you know how the flow route operates, you will discover that the CDU is very much like a book with several hundred pages of information that is easily accessible via a few select menu keys.

As with all my posts, if you discover a discrepancy please contact me so it can be rectified.

BELOW: Montage of images from the CDU showing various pages displayed within the Reference Nav Data. CDU is manufactured by Flight Deck Solutions (FDS). Click image to see larger.

Montage of images from the CDU showing various pages displayed within the Reference Nav Data. CDU is manufactured by Flight Deck Solutions (FDS)

January 11, 2013

Replacement Sidewalls for FDS MIP

January 11, 2013/ Flaps 2 Approach

I have mentioned in an earlier post concerning the Main Instrument Panel (MIP) from Flight Deck Solutions, that the unit was a little wobbly due to the thin metal used on the side-walls. Whilst this is not a huge problem and certainly not an issue when the MIP is locke" into a shell, it does pose a minor issue when used without a shell. Therefore, I decided to fabricate some replacement side stands for the MIP from 3mm aluminium sheet.

AutoCad was used to copy the dimensions of the original FDS sidewalls, and a lazer cutter cut the aluminium sheeting to the exact measurement. Using a standard pipe bender, I bent the sides out at 45 degrees to allow slightly larger spacing for the rudder pedals. I also increased the surface area of the metal which is used to attach the MIP to the platform, this ensures a more stable and secure attachment point for the MIP. To replicate the MIP side-walls exactly, I TIG welded the narrow section that folds behind the stand.

Currently the aluminum is unpainted. At some stage in the near future I'll either have the two units powder-coated in Boeing grey to match the colour of the MIP, or more than likely I'll prime and paint them myself.

The MIP is now very stable and does not wobble at all.