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Mission Statement 

The purpose of FLAPS-2-APPROACH is two-fold:  To document the construction of a Boeing 737 flight simulator, and to act as a platform to share aviation-related articles pertaining to the Boeing 737; thereby, providing a source of inspiration and reference to like-minded individuals.

I am not a professional journalist.  Writing for a cross section of readers from differing cultures and languages with varying degrees of technical ability, can at times be challenging. I hope there are not too many spelling and grammatical mistakes.

 

Note:   I have NO affiliation with ANY manufacturer or reseller.  All reviews and content are 'frank and fearless' - I tell it as I see it.  Do not complain if you do not like what you read.

I use the words 'modules & panels' and 'CDU & FMC' interchangeably.  The definition of the acronym 'OEM' is Original Equipment Manufacturer (aka real aicraft part).

 

All funds are used to offset the cost of server and website hosting (Thank You...)

No advertising on this website - EVER!

 

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If you see any errors or omissions, please contact me to correct the information. 

Journal Archive (Newest First)

Entries by FLAPS 2 APPROACH (199)

Sunday
Apr292018

ISFD Knob Fabricated

The Integrated Standby Flight Display (ISFD) is mounted in the stand-by instrument cluster in the Main Instrument Panel (MIP).  The ISFD provides redundancy should the Primary Flight Display (PFD) on the Captain or First Officer fail. 

LEFT:  OEM ISFD (Image copyright Driven Technologies INC).

The ISFD is not a common panel to find second hand, and working units are expensive to purchase.  I don't  have an OEM ISFD, but rather (at least for the moment) use a working virtual image displayed by ProSim737. 

Conversion of an OEM unit is possible, however, the unit would need to be fully operational, and  finding a working unit at a reasonable price is unlikely.  ISFDs are expensive and reuse is common.  If a unit does not meet certification standard, it's disposed of because it's broken and cannot be economically repaired.

ISFD Knob

LEFT:  ISFD knob.  Two versions: one replicates the taller NG style while the other is slightly shorter.  Although not functional, they provide a better representation of the plastic knob that previously was installed.  (Click to enlarge).

The ISFD knob that came bundled with the MIP I purchased is very mediocre in appearance – in fact it's a piece of plastic that barely looks like a realistic knob.  I purposely have not included an image, as the design would be an embarrassment to the company that produced the MIP.

LEFT: Knob being fabricated on a lathe.  This photograph has been taken by another person and is not my property (click to enlarge).

A friend of mine is a bit of a wizard in making weird things, so I asked him if he could make a knob for me.  He made two knobs – one based on the standard design seen in the Next Generation airframe and the other knob a shorter version of the same type. 

Attention to Detail

Attention to detail is important and each knob has the small grub screw and cross hatch design as seen on the OEM knob.  The knobs have been made from aluminum and will be primed and painted the correct colour in the near future.

A 2 axis CNC lathe was used to fabricate the knobs.  The use of a computerised lathe enables the measurements of a real knob to be accurately duplicated, in additiona to any specoifc design (such as cross hatching or holes to install grub screws).

Saturday
Mar032018

Wind Correction (WIND CORR) Function - CDU

Wind Correction (WIND CORR)

The approach page in the CDU has a field named WIN CORR (Wind Correction Field or WCF).  Using WIND CORR, a flight crew can alter the Vref+ speed (additive) that is used by the autothrottle to take into account headwinds greater than 5 knots. 

LEFT:  OEM CDU showing WIND CORR display in Approach Ref page (click to enlarge).

The default reading is +5 knots.   Any change will alter how the FMC calculates the command speed that the autothrottle uses.  Any change is reflected in the LEGS page. 

It's important to update the WIND CORR field if VNAV is used for the approach or of executing an RNAV Approach, as VNAV uses data from the Flight Management System to fly the approach.   However, if hand flying the aircraft, or executing an ILS Approach, it's often easier to add the Vref additive to the speed window in the MCP.  Indeed, flight crews for the most part, other than when using VNAV, leave the WIND CORR as its default (+5 knots), and change airspeed by using the MCP or by using Speed Intervention (SPD INTV).

WIND CORR Explained

The ability to increase the Vref speed is very handy if a flight crew wishes to increase the safety margin the autothrottle algorithm operates.

Boeing when they designed the autothrottle algorithm programmed a speed additive that the A/T automatically adds to Vref when the A/T is engaged.  The reason for adding this speed is to provide a safety buffer to ensure that the A/T does not command a speed equal to or lower than Vref.   (recall that wind gusts can cause the autothrottle to spool up or down depending upon the gust strength). 

A Vref+ speed higher than +5 can be inputted when gusty or headwind conditions are above what are considered normal.  By increasing the +speed, the  speed commanded by the autothrottle will not degrade to a speed lower than that inputted.

How To Use WIND CORR

WIND CORR is straightforward to use.   

Navigate to the approach page in the CDU (press INIT REF key to open the Approach Reference page).  Then double press the key adjacent to the required flaps for approach (for example, flaps 30).  Double selecting the key causes the flap/speed setting to be automatically populated to the FLAP/SPD line. 

It’s important to understand that this is the Vref.  This calculation ALREADY has the +5 additive added; this is the speed that the aircraft should be at when crossing the runway threshold.  

LEFT:  Virtual CDU (ProSim-AR) showing the difference in Vref between a +5 and +13 Knot Wind Correction change.  Vref altered from 152 knots to 160 knots (click to enlarge).

If the headwind is greater than 5 knots, then WIND CORR can be used to increase the additive from the default +5 knots to anything up to but not exceeding 20 knots. 

Type the desired additive into the scratch pad of the CDU and up-select to the WIND CORR line.  The revised speed will change the original Vref speed and take the headwind component into account.  If you navigate to the LEGS page in the CDU, you will observe the change. 

Note that the Vref speed displayed on the Primary Flight Display (PFD) does not change.  This remains at Vref +5.

For a full review on how to calculate wind speed, review this article: Crosswind landing Techniques - Calculations, or read the cheat sheet below.         

LEFT:  Wind calculation cheat sheet (click to enlarge).

Important Varibles - Aircraft Weight

To obtain the most accurate Vref for landing, the weight of the aircraft must be known minus the fuel that has been consumed during the flight.

Fortunately, the Flight Management System updates this information in real-time and provides access to the information in the CDU.  It's important that if an approach is lengthy (time consuming) and/or involves holds, the Vref data shown will not be up-to-date (assuming you calculated this at time of descent); the FLAPS/Vref display will show a different speed to that displayed in the FLAP/SPD display.  To update this data, double press the key adjacent to the flaps/speed required and the information will update to the new speed.

Interestingly, the difference that fuel burn and aircraft weight can play in the final Vref speed is quite substantial (assuming all variables, except fuel, are equal).  To demonstrate:

  • Aircraft weight at 74.5 tonnes with fuel tanks 100% full – flaps/Vref 30/158.
  • Aircraft weight at 60.0 tonnes with fuel tanks 25% full   – flaps/Vref 30/142.

 Important Points:

  • During the approach, V speeds are important to maintain.  A commanded speed that is below optimal can be dangerous, especially if the crew needs to conduct a go-around, or if winds suddenly increase or decrease.  An increase or decrease in wind can cause pitch coupling.
  • If executing an RNAV Approach, it's important to update the WIND CORR field to the correct headwind speed based on conditions.  This is because VNAV uses the data from the Flight Management System (FMS).
  • If an approach is lengthy, the Vref speed will need to be updated to take into account the fuel used in the aircraft.  

Autoland

Autolands are rarely done in the Boeing 737, however, if executing an autoland, the WIND CORR field is left as +5 knots (default).  The autoland and autothrottle logic will command the correct approach and landing speed.

Functionality

WIND CORR may or may not be functional in the avionics software you use.  It is 100% functional in the ProSim-AR 737 avionics suite (Version 2).

Acronyms

CDU – Control Display Unit
FMC – Flight Management Computer
FMS – Flight Management System (comprising the FMC and CDU)
Vref - The final approach speed is based on the reference landing speed
Vapp – Vapp is your approach speed, and is adjusted for any wind component you might have. You drop from Vapp to Vref usually by just going idle at a certain point in the flare

Thursday
Feb012018

Variation in Panel Colour, Manufacture & Location - Center Pedestal

The center pedestal in the Boeing 737 accommodates a number of panels, several of which are standard for all commercial passenger airlines.  All high-end simulators replicate these panels and enthusiasts often fixate on several issues.  Namely:

(i)         The colour of the panel and lightplate;

(ii)        The position of the panel in the center pedestal;

(iii)       The backlighting of the lightplate (bulbs verses LEDs);

(iv)       The manufacturer of the panel, and;

(v)        The aesthetic condition of the lightplate.

Although seemingly important to a cockpit builder, to the casual observe, or indeed to many pilots, these attributes are of little consequence.  Nevertheless, it's understandable why many believe all the panels are identical in all B737 airframes.

Whilst it's true that all airlines must meet aviation standards for the type of operation they fly, the panel manufacturer and where in the pedestal the panel is located is at the discretion of the airline.  Furthermore, it's not uncommon to observe older style panels mixed with modern panels and to see lightplates that are illuminated by bulbs and LEDs side by side.

Note that some of this information probably pertains more to older Next Generation 737s than to the latest airframe build released from Boeing.  I use the word 'panel' to denote an avionics module.

Colour of Lightplates

The official colour shade used by Boeing is Federal Standard 5956 36440 (light gull grey).  However, OEM part manufacturers may use slightly different colour hues.  For example, IPECO use British Standard 381C-632 (dark admiralty grey) and Gables use RAL 7011.  This said, often an airline will 'touch up' a lightplate that is damaged or faded - this introduces a further colour variant. 

LEFT:  Air Alaska 737-700 pedestal.  Note higher than standard position of ACP panels and relocated position of the door lock panel.  Also high mounted position of rudder trim panel (click to enlarge).

As an example, a lightplate I repaired from a B737-500 airframe revealed three differing shades of grey beneath the final top coat of paint.  This is not to mention that, depending on the manufacturer of the lightplate, the final coat of paint may be matt, semi-matt or gloss.

From the perspective of an engineer, the colour (and to a certain extent aesthetic  condition) is unimportant when replacing a defective part with another.  Time spent in the hanger equates to a loss in revenue by the airline.  Therefore turn-around times are as brief as possible and keeping an aircraft on the ground while procuring the correct shade of Boeing grey does not enter the equation.

Position of Panels in the Center Pedestal

Boeing recommends a more or less standard position for the essential panels in the center pedestal (NAV, COM, ADF, ASP, rudder trim, door lock and panel flood), however, the location of the panels is often altered by the receiving airline, and is to a certain extent is determined by what other panels are installed to the pedestal.  Areas (holes) in the pedestal not used by a panel are covered over with a grey-coloured metal blank.

LEFT:  This photograph of the center pedestal of a Boeing 737-500 was taken in 2016.  The aircraft is a freighter used to transport parcels that has been converted from a passenger aircraft.  Apart from the older style ACP panels, note the disparate displays between the NAV and COM radios.  Also note the position of the ADF radios and some of the other panels; they do not conform to what is usually thought of as a standard set-out.  Finally, note the scratches on the pedestal and on some of the panels and lightplates - they hardly look new (click to enlarge).

Panels are manufactured by several companies, and often there appearance will differ slightly between manufacturer, although the panel's functionality will be identical.  The airline more often than not chooses which panel is used, and often the decision is biased by the cost of the panel.  Therefore, it's not uncommon to observe several airframes of a similar age with differing panels positioned in different areas of the center pedestal.

Panel Condition

Enthusiasts pride themselves in having a simulator that looks brand new.  However, in the real world a Level D simulator or flight deck rarely looks new after entering service.  Panels can be soiled and paint is chipped and scratched, and depending on age, some lightplates are faded to due to the high UV environment that is present in a flight deck.

So where am I going with this?  Enthusiasts strive to match their panels with those observed in a real airliner, however, more often than not this information comes from photographs distributed by Boeing Corporation (which nearly always depict panels in a standard position in the center pedestal). 

The variables noted by enthusiasts should not cause consternation, as real aircraft show similar variation.  Remember that in the real aircraft, colour, manufacturer, and to a certain extent aesthetic condition is not important - functionality is.

To see additional photographs, navigate to the image portal.

Tuesday
Dec192017

Maintaining Backlighting Brightness Across OEM and Reproduction Panels

Many enthusiasts are now using Original Aircraft Equipment (OEM) panels in their simulators.  These panels are connected to Flight Simulator using a variety of interface cards.  Unless the flight deck uses all OEM panels, or all reproduction panels, there will be a difference in backlighting when the light plates are illuminated.

LEFT:  FDS-IBL-DIST-DIM.  A card that makes diming backlighting very easy.  Potentiometer is not shown (click to enlarge).

Reproduction panels, with the exception of expensive very high end types, will have exceptionally bright backlighting.  Manufacturers of reproduction panels want their panel to look good and appeal to a prospective buyer – this is why they have bright backlighting.  In contrast, OEM panels do not have  bright backlighting, and in some cases, depending upon the manufacturer of the panel, the backlighting will appear rather dim.  

Therefore, the brightness of the backlighting when using ‘run of the mill’ reproduction panels is not realistic in comparison to that observed in a real aircraft.

So how does a cockpit builder solve this conundrum of brightness if he or she has a mix of reproduction and OEM panels.  The solution is very simple – install a dimmer switch into your flight deck.

Dimmer Control

There are a number of 5 volt dimmer switches on the market and some are better than others.  For those with electrical knowledge it’s relatively straightforward to make your own dimmer switch, but what about the rest of us?  An excellent solution is the distribution board with built in dimmer control manufactured by Flight Deck Solutions (FDS).  The board keeps with the principle of KIS (keep it simple).  

FDS-IBL-DIST-DIM

The distribution board is well made, small, is fuse protected, and have the capability to connect up to 14 accessory LEDS or bulbs via propriety board connectors.  The board also can be used as a slave, meaning it can be daisy-chained to another board to increase the number items attached.

The distribution board includes a pre-wired metal potentiometer which allows all the LEDS/bulbs attached to the board to be dimmed from on to off or anywhere in-between.  The potentiometer is a standard size and fits the hole located in the panel lights panel on either a reproduction panel or an OEM panel.

One limiting feature that should be noted is that each distribution board will only support 10 amps - the rating of the fuze. 

Of more importance, the board operates flawlessly and is a very easy solution to maintaining an even brightness across reproduction and OEM panels; adjust the brightness of the reproduction panels to the same level as the OEM panels.

Connection

Connection is straightforward and requires +- 5 volts to be connected to the board.  Each LED (or bulb) that requires dim control is then connected to the board connectors.  If using an FDS panel this is very easy as the FDS panels already use the correct female attachment plugs (FDS also use bulbs and not LEDS).  Failing this, a little extra work is required to source the correct plugs and wire them to the +- wires that connect to the light plate.

Bulbs and LEDS

On another note, with the exception of late model airframes, the Next Generation B737 use 5 volt incandescent bulbs in their panels for backlighting.  This is in contrast to reproduction panels that, for the most part, use LEDS.  

The difference between bulbs and LEDS, other than construction, is the temperature they generate when turned on.  A bulb will generate considerable heat and the colour of the light will appear as a warmer hue.  A LED does not generate heat when turned on.  Therefore, an LED will have a cooler temperature and the colour of the light will be colder and more stark in its appearance.

However, before changing out all your bulbs or LEDS to maintain colour consistency, study the flight deck of a real aircraft.  Panels on all aircraft fail or need upgrading from time to time.  Therefore, it is not unrealistic o have a flight deck consisting of both LEDS and bulbs.  Airlines are in the business of making money, and pilots fly.  Neither are particularly interested in whether the ADF radio has a bulb or LED.

Additional Information

Soar-By-Wire has also discussed this subject.  Although his information relates to the Airbus, the same proceedure can be done for Boeing OEM panels.

Disclaimer

I do not represent Flight Deck Solutions or any other manufacturer and have no received any fee or reward for discussing one of their interface components.

Further information pertaining to the distribution board can be found on the Flight Deck Solutions website.

A fellow enthusiast has written more information on his website about the distribution board as it relates to Airbus - Soarbywire.  What he has written is well worth the time reading.

Friday
Nov172017

Sounds Reworked - Flight Sim Set Volume (FSSV) - Review

Immersion is a perception of being physically present in a non-physical world.  The perception is created by surrounding the user of the simulator in images, sound or other stimuli that provide an engrossing total environment.  When something does not replicate its real world counterpart, the illusion and immersion effect is degraded.

LEFT:  Engine sounds will be at their highest at takeoff.

Engine Sound Output

The sound output generated by a jet aircraft as heard from the flight deck is markedly different when the aircraft is at altitude.  This is because of differences in air density, temperature, the speed of the aircraft, drag, and thrust settings.  The noise emitted from the engines will always be highest at takeoff when full thrust is applied.  At this time, the noise generated from wind blowing over the airframe will be at its lowest.  At some stage, these variables will change and wind noise will dominate over engine noise.

As an aircraft gathers speed and increases altitude, engine sound levels lower and wind levels, caused by drag, increase.  Furthermore, certain sounds are barely audible from the flight deck on the ground let alone in the air; sounds such the movement of flaps and the extension of flight spoilers (speedbrake).

Being a virtual flyer, the sound levels heard and the ratio between wind and engine sound at altitude is subjective, however, a visit to a flight deck on a real jet liner will enlighten you to the fact that that Flight Simulator’s constant-level sound output is far from realistic.

Add On Programs

Two programs which strive to counter this shortcoming (using different variables) are Accu-Feel by A2A Simulations and FS Set Volume (FSSV).  This article will discuss the attributes of FSSV (Sounds Reworked).

Flight Sim Set Volume (FSSV)

FSSV is a very basic program that reads customized variables to alter the volume of sound generated from Flight Simulator.  The program is standalone and can be copied into any folder on your computer, however, does require FSUIPC to connect with Flight Simulator.  Wide FS enables FSSV to be installed on a client computer and run across a network.  

The following variables can be customised:

(i)     Maximum volume
(ii)    Minimum volume
(iii)   Upper mach threshold
(iv)   Lower mach threshold
(v)    Engine volume ratio

Each of the variables will alter to varying degrees the Mach, engine %N1, rounded engine speed and volume percentage.  

For the program to have effect it must be opened either prior to or after the flight simulator session is opened. 

LEFT:  FSSV pop-up screen showing customised variables (default) that can be set and current reads-outs for the simulator session (click to enlarge).

It’s an easy fix to automate the opening of the program to coincide with Flight Simulator opening by including the program .exe in a batch file

A pop-up window, which opens automatically when the program is started, will display the variables selected and the outputs of each variables.  If the window is kept open, the variables can be observed ‘on the fly’ as the simulation session progresses.  Once you are pleased with the effects of the various settings, a save menu allows the settings to be saved to an .ini file.  The pop-up window can then be set to be minimized when you start a flight simulator session.  

How FSSV Works

The program reads the sound output from the computers primary sound device and alters the various sound outputs based upon customized variables.  The program then lowers the master volume at the appropriate time to match the variables selected.  FSSV will only alter the sound output on the computer that the program is installed.  Therefore, if FSSV is installed to the same computer as Flight Simulator (server computer) then the sound for that computer will only be affected.

Possible Issue (depends on set-up)

An issue may develop if FSSV is installed on a client computer and run across a network via Wide FS, then the program will not only affect the sound output from the server computer, but it also will affect the sound output from the client computer.  

A workaround to rectify this is to split the sound that comes from the sever computer with a y-adapter and connect it to the line-in of another computer, or use a third computer (if one is spare).

In my opinion, it’s simpler to install and run the program via a batch file on the server computer that flight simulator is installed.  The program is small and any drop in performance or frame rates is insignificant.

Summary

The program, although basic, is very easy to configure and use - a little trial and error should enable the aircraft sounds to play with a higher degree of realism.  However, the level that you alter the variables to is subjective; it depends on your perception to the level of sound heard on a flight deck – each virtual flyer will his or her own perception to what is correct. 

The program functions with FSX and P3D flawlessly. 

Finally, If you are unhappy with the result, it’s only a matter of removing/deleting the folder you installed the program to, or close the program during your simulator session to return the sound levels to what they previously were.  FS Set Volume can be downloaded at no charge at http://forum.simflight.com/topic/81553-fs-set-volume/.  

Video

The below video is courtesy of the FSSV website.