737-800 Landing Procedure

 
 

737-800 Transocean Air on finals Komatsu (RJNK) Airport, Japan

In this article I will discuss the techniques used to land the 737-800 aircraft.  

The choice of landing approach is often influenced by considerations such as the specific criteria required for the approach, the desired level of automation, and the individual pilot's preference and technique. Regardless, the procedure used to actually land the aircraft is similar in all approach types.

The first part of the article discusses techniques used in the approach, descent and landing.  This is followed by a short recap regarding situational awareness, which is critical in any approach and landing.  At the end there is a downloadable step guide explaining the procedure to land the 737-800.

Discussing landing technique without addressing the approach is counter intuitive.  As such, a generic style approach has been ‘loosely’ used to provide a frame of reference.  Furthermore, in an effort to ensure clarity and provide sufficient context, certain information discussed in previous articles may have been reiterated. I purposely have not included or discussed detailed checklists.

I have attempted to include as much information as possible which, can have a tendency to make the subject appear complicated; it is not complicated.  Carefully read the information and note that:

  • There is a considerable variability in how the 737 is flown.  Certainly there are wrong ways to do things, however, there is no single right way to do it; and,

  • Airline policy often dictates how an approach is flown based on whether it is a Precision Approach or a Non Precision Approach.

Generally speaking, an approach can be segregated into three segments:

  • The initial approach;

  • The landing approach (descent phase); and,

  • The final approach (landing phase).

Discussion

Initial Approach

Technically, the approach starts when entering the traffic pattern, terminal airspace or at the Initial Approach Fix (IAF), which is published on the approach chart.  However, not all approaches have an IAF, and some require that the airplane be vectored to the final approach course by Air Traffic Control.   Even if there is an IAF, ATC may still decide to vector a plane to the final approach course to make more efficient use of airspace.

Prior to reaching the IAF, or receiving vectors to final, the flight crew should have prepared the aircraft for approach, briefed the crew, and begun to slow the aircraft.  Workload increases considerably during the descent; therefore, it is sensible to complete whatever can be completed prior to the descent point. Descent planning and preparation is usually completed before the initial approach segment begins, which is approximately 25 miles from the runway.

Important Points:

  • Approach planning should be completed prior to the descent point.

  • In general, unless indicated otherwise, a flight crew will want the aircraft at approximately 3000 ft AGL no less than 10 NM from the runway.

Landing Approach

When reaching the IAF or descent point (for brevity, I will refer to the descent point as the IAF for the remainder of this article), the aircraft will in all probability be controlled by the autopilot with guidance being controlled by LNAV and VNAV (or another pitch/roll mode).

Depending on the type of approach chosen, the aircraft will be transitioning from level flight to either a step-down approach (SDA) or a continuous descent approach (CDA).  Step-down approaches are rarely used today; continuous descent approaches are more the norm.  A CDA, unless otherwise stated on the approach chart, uses a 3 degree glide path.

If you examine the two approach charts (click to enlarge) you will note that the VOR 06 approach shows the descent point at HERAI at 1455 ft AGL. The point is marked by a Maltese Cross and is also shown as the FAF (Final Approach Fix) in the distance legend. Also note that both a step down and a continuous approach is displayed on the chart. In the second chart (ILS 06) the descent point is shown as a LOC (localizer) at 1964 ft AGL and the FAF is noted in the distance legend. Note the chart is also annotated IF (Initial Fix). Different charts will display different annotations.

The reason for showing these two charts, is to demonstrate that the descent point and distance from the runway to begin the descent, will change depending upon the approach type selected from the FMC (assuming an approach from the FMC is used).

 

RJNK VOR 06

 

RJNK ILS 06

 

‘Loose’ Recommendation

As I have already mentioned, there are multiple ways to approach and land the 737; ask several pilots and each opinion will be slightly different. Generally speaking, without alternate guidance from Air Traffic Control or an approach chart, the following recommendations should be adhered to. The aircraft should begin descent to the runway at:

  • Approximately 10 NM from the runway;

  • At approximately 3000 ft AFE;

  • Have flaps 1 extended; and,

  • Be flying at as airspeed no greater than 200 kias.

If the aircraft is following the ILS approach course, it is better to intercept the ILS glideslope slightly from below rather than above. Intercepting the glideslope from below enables greater control of airspeed.

Speed Management

Speed management is probably the most critical factor during any approach.  A common saying is ‘you have to slow down to get down’. This said, it is a bit of a corundum. The airline wants its pilots to optimise the aircraft’s airspeed for as long as possible, because this means less fuel use, less noise, and lower engine operation times.

Slowing the 737-800 aircraft is not easy when the aircraft is descending, so it is a good idea to begin to reduce the airspeed when the aircraft is in level flight prior to beginning the descent. The thrust levers should be brought to idle (idle thrust or near to) and the airspeed allowed to decay to the flaps UP maneuvering speed.  The flaps UP indication is displayed on the speed tape in the PFD. If speed reduction is initiated before reaching the IAF, the airspeed will decay naturally without use of the speedbrake. 

Important Points:

  • It requires approximately 25 seconds and 2 NM to decelerate the 737-800 from 280 kias to 250 kias, and it will take a little longer decelerating from 250 kias to 210 kias. More simply written, it takes approximately 1 NM to decrease airspeed by 10 kias in level flight.

  • The aircraft should begin slowing at 15 NM from the airport to be at 10 NM at 3000 ft AFE at a speed of approximately 190-200 kias with flaps 1 extended.

Speedbrake and Flaps Use

The transition from level flight to descent will be much easier, with less need to use the speedbrake, if the aircraft is already at a lower airspeed prior to the descent.  If the speedbrake must be used, try to minimise its use at and beyond flaps 5.  With flaps 15 extended the speedbrake should be retracted. The speedbrake should not be used below 1000 ft AGL. 

Although the speedbrake is designed to slow the aircraft, its use causes increased inside cabin buffeting and noise, decreases fuel efficiency, and can lead to unnecessary spooling of the engines; these factors are exacerbated if the aircraft is descending and travelling at a slower speed. If the speedbrake is to be used during the descent, lower the speedbrake (clean configuration) before adding thrust, otherwise thrust settings will need to be adjusted.

It must be stressed that using the flaps to slow down by creating more drag is not good technique and is frowned upon.  Additionally, continual use of the flaps to slow an aircraft can cause damage to the flaps mechanism over a period of time - adhere to the flaps extension schedule (discussed shortly).

If the aircraft’s speed is too high and the approach is too fast, lowering the landing gear early is an excellent way to slow the aircraft, but bear in mind that this will also increase drag, generate noise, and increase fuel consumption.  This should only be done as a last resort.

Important Points:

  • Whenever the speedbrake is used, the pilot flying should keep his hand on the speedbrake lever. This helps to prevent inadvertently leaving the speedbrake lever extended. 

  • Flaps, in principle, are not designed to slow the aircraft; the aircraft’s pitch, thrust, and the use of the speedbrake do this.

Flaps Extension Schedule

All to often novice virtual flyers do not adhere to the flaps extension schedule.  Extending the flaps at the incorrect airspeed can cause high aircraft attitudes, unnecessary spooling of engines, excessive noise, and increased fuel consumption which can lead to an unstable approach. If the flaps are extended at the correct airspeed, the transition will be relatively smooth with minimal engine spooling.

The correct method to extend the flaps is to extend the next flaps increment when the airspeed passes through the previous flaps increment.  For example, when the airspeed passes through the flaps 1 indication, displayed on the speed tape in the PFD, select flaps 2.

The 737 has 8 flap positions excluding flaps UP.  It is not necessary to use all of them.  Flight crews will often miss flaps 2 going from flaps 1 to flaps 5. Similarly, flaps 10 may not be extended going from flaps 5 directly to flaps 15 and flaps 25 maybe jumped over selecting flaps 30. Flaps 30 in the norm for most landings with flaps 40 being reserved for short-field landings or when there is minimum landing distance. In the case of using flaps 40, flaps 25 is normally extended.

My preference is to use flaps 25 as it makes the approach a little more stable, especially if the flaps have been extended some distance from the runway.  However, if you are conducting a delayed flaps approach, selecting flaps 25 may not give you enough time to extend flaps 30 or 40 and complete the landing checklist before transitioning below ~ 1500 feet AGL.

Flaps 40

The use of flaps 40 should not be underestimated, as aircraft roll out is significantly reduced and better visibility is afforded over the nose of the aircraft (because of a lower nose-up attitude). Because the landing point is more visible, some flight crews regularly use flaps 40 in low visibility approaches (CAT II & III). If the aircraft’s weight is high, the runway is wet, or there is a tailwind, flaps 40 is beneficial. A drawback to using flaps 40, however, is the very slow airspeed (less maneuverability) and higher thrust required. For this reason, if there are gusting winds it is better to use flaps 30.

Advantages

  • Less roll out;

  • Better visibility over the nose of the aircraft due to lower nose-up attitude;

  • Less wear and tear to brakes as the brakes are generating less heat (faster turn around times);

  • Less chance of a tail strike because of slightly lower nose-up attitude during flare;

  • More latent energy available for reverse thrust (see note); and,

  • Helpful when there is a tailwind, runway is wet, or aircraft weight is high.

Disadvantages

  • Increased fuel consumption (negligible unless flaps 40 are extended some distance from runway);

  • Increased drag equating to increased noise (flaps 40 generates ~10% additional thrust); and,

  • Less maneuvering ability.

NOTE: When the aircraft has flaps 40 extended, the drag is greater requiring a higher %N1 to maintain airspeed. This higher N1 takes longer to spool down when the thrust levers are brought to idle during the flare; this enables more energy to be initially transferred to reverse thrust. Therefore, during a flaps 40 landing more energy is available to be directed to reverse thrust, as opposed to a flaps 30 landing.

Important Point:

  • Correct management of the flaps is selecting the next lower speed as the additional drag of the flaps begins to take effect.   

 

TABLE 1: Flaps Extension Table. The table does not include flaps 2, 10 & 25. © JAL-V

 

Maneuvering Margin

The maneuvering margin refers to the airspeed safety envelope in which the aircraft can be easily maneuvered.  This is pertinent during descent, as when the aircraft slows down its ability to maneuver is less than optimal.  An adequate margin of safety exists when the airspeed is at, or slightly above the speed required with the flaps extended.  This is displayed in the speed tape in the PFD. 

Pitch and Power Settings (Fly By The Numbers)

Whenever the aircraft is flown by hand (manual flight), pitch and power settings become important.  A common method used by experienced pilots is to fly by the numbers.

The term fly by the numbers is when the pilot positions the thrust levers commensurate to a desired %N1.  The %N1 is based on aircraft weight and is displayed in the EICAS.   If the figures are not available, a reasonable baseline %N1 to begin with is around 55%N1.  Aircraft with heavier weights will require higher thrust settings while lower thrust settings will be needed for lighter weights.  The thrust setting is arbitrary and %N1 will need be fine-tuned with small adjustments.

Once the thrust has been set, always allow the thrust to stabilise for a few seconds and ensure that both thrust levers display an identical %N1.  If you fail to do this, and the thrust settings are slightly offset (despite the thrust levers being beside each other) the aircraft will turn in the direction of least thrust (asymmetric thrust).

Important Point:

  • The %N1 is a baseline figure, the correct %N1 will depend on the weight of the aircraft and any wind component. 

It is almost miraculous that once the correct thrust has been set, the others numbers that relate to airspeed and rate of descent fall into place, and the aircraft will only require small incremental adjustments to maintain a 3 degree glide path.

Recommendation:

  • In order to gauge how the aircraft reacts during an approach, fly several automated approaches (the easiest to fly is the ILS Approach).  Observe the thrust settings (%N1) as you extend the flaps and lower the landing gear.  Note the numbers for the particular weight of the aircraft. 

Reaching the Descent Point

If the aircraft’s airspeed has been managed appropriately, initiating the descent at the IAF is relatively straightforward.  During descent the aircraft should:

  • Have the thrust levers set to idle thrust (or near to);

  • Have an attitude of approximately 5 degrees nose-up;

  • Maintain a constant rate of descent (sink rate) between ~600-800 ft/min;

  • Be on a constant 3 degree glide path; and,

  • Not have a descent rates greater than 1000 ft/min. 

If you are uncertain to the glide path being flown, refer to the Flight Path Vector (FPV) in the PFD.

During the initial descent phase:

  • Speed is controlled by pitch; and,

  • Rate of descent is controlled by thrust.

As you transition to the final approach phase, this changes and:

  • Speed is controlled by thrust; and,

  • Rate of descent is controlled by pitch.

Model aircraft is used to visualise various approach and landing attitudes

The above dot points confuse many virtual flyers and trainees alike.  Rather than attempting to visualise this in your mind, use a small model airplane and position the model in a particular flight phase with the correct attitude.  After a while it will make sense and become second nature.

Descent

Plan to be at, or just before the descent point at flaps UP or flaps 1 maneuvering speed.   If concerned that the airspeed is too fast, slow the aircraft to a speed that corresponds to the flaps 1 or flaps 2 indications displayed on the speed tape.   The airspeed will usually fall between 210-190 kias.

After initiating the descent in idle thrust and with the aircraft’s attitude set to approximately 5 degrees nose-up, the aircraft’s airspeed will slowly decay.  As the aircraft slows, match the airspeed to the flap indications on the speed tape.   The maximum airspeed during the descent should not exceed Vref +20 or the landing placard speed minus 5 knots – whichever is lower (Boeing FCTM, 2023). 

Vref +20 is indicated by the white carrot on the speed tape.  The white carrot will be displayed when Vref is selected in the CDU. 

Lowering the Landing Gear (General Rule)

A rule of thumb used by many flight crews in favourable weather conditions is to lower the landing gear and select flaps 15 at ~7 NM from the runway threshold.   At this distance, the aircraft’s altitude is ~2500-2000 ft AGL, and then, prior to reaching 1500 ft AGL, select landing flaps (25, 30 and/or 40).  This enables ample time to ensure that the aircraft is stabilised, and to complete the landing tasks and landing checklist. 

As an aid, flight crews typically will place a ring at the distance that the landing gear is to be lowered. This is displayed on the Navigation Display.  The ring, created in the CDU, provides a visual reference as to when to lower the landing gear. A ring is also often added at the IAF.

Delayed Flaps Approach

Some airlines and pilots use less conservative distances, thereby minimising the time that the aircraft is flying with the landing gear lowered and flaps extended. A delayed flaps approach or minimum noise approach, will usually have the landing gear lowered and flaps 15 extended at 4 NM from the runway. Landing flaps will then be extended very soon after.

Caution - Delayed Flaps Landing

While lowering the landing gear and extending the landing flaps close to the runway threshold has positive benefits to the airline, and does limit the noise generated, it is not without its problems. Potential problems are:

  • If there is a landing gear or flaps failure, the aircraft is very close to the ground;

  • The landing checklist must be done quickly when concentration may be needed elsewhere (landing);

  • If the aircraft’s airspeed is too high, slowing down is difficult at this late time; and,

  • If windshear or other weather related events occur the aircraft is very close to the ground with minimal room to escape.

When the landing gear is lowered and the landing flaps are extended, the aerodynamics of the aircraft are significantly changed. The pilot must be prepared to adjust the flight controls (pitch and thrust) to maintain control; this is especially so when hand-flying the aircraft. Being in close proximity to the ground at this stage can amplify the risk of a ground strike should the pilot have difficulty adapting to the altered aerodynamics.

Lowering the landing gear and extending the flaps, at a distance of 7-5 nautical miles from the runway, provides additional time and a crucial safety buffer for the pilot to acclimate to the new aerodynamic conditions.

Important Points:

  • The 737-800 is renown for being slippery and difficult to slow down, which is why it is recommended to slow the aircraft prior to the IAF. 

  • A Rule of Thumb often used is: It takes approximately 3 NM to loose 1000 ft of altitude (assuming flaps UP maneuvering speed).

  • A delayed flaps landing should be attempted only in optimal weather conditions.

If you slow the aircraft prior to reaching the IAF, maintain the correct thrust settings to aircraft weight, and extend the flaps at their correct speeds, the approach will usually be within acceptable limits. You will also not have to use the speedbrake.

Stabilised Approach

During the final approach the aircraft must be stabilised; if the approach becomes unstable and the aircraft descends below 1000 feet AFE in IMC, or 500 feet AFE in VMC, an immediate go around must be initiated.

An approach is considered stable when the following parameters are not exceeded:

  • The aircraft is on the correct flight path;

  • Only small changes in heading and path are needed to maintain the correct flight path;

  • The power settings for the engines are appropriate to the aircraft’s configuration;

  • The aircraft’s airspeed is no more than Vref +20 kias and not less than Vref (plus wind component); and,

  • The descent rate of the aircraft is no greater than 1000 ft/min (no special briefing).

Stability during an approach is made considerably easier if the aircraft:

  • Is travelling at the correct airspeed;

  • Is trimmed correctly for neutral stick.

  • The flaps are extended at the correct flaps/speed ratio;

  • The attitude (pitch) is correct; and,

  • The thrust settings are commensurate with the desired airspeed and rate of descent.

Final Approach

The final approach, flare and touchdown occurs very quickly. 

At 500 ft AGL, the pilot should begin to include the outside environment in their scan. This adjustment allows for better situational awareness and helps in preparing for a smooth landing.

As the aircraft descends further to 200 ft AGL, the approach becomes predominantly visual. During this phase, the pilot relies heavily on external visual references to maintain proper alignment of the aircraft (runway cues, approach lighting, and other visual references).

Select a part of the runway where you want to the land (use the runway aiming markers) and adjust the attitude of the aircraft so that it is aimed at this location.  For guidance, the runway centerline should be running between your legs.

As the aircraft flies over the runway threshold (piano keys) and when you hear the fifty call-out, adjust your viewpoint from the aiming point to approximately 3/4s down the runway.  I find looking at the end of the runway works well, as I can see the horizon which aids in determining if the wings are level and in determining the sink rate.

Flare and Touchdown

The flare is a term used to describe the raising of the aircraft’s nose, by approximately 2-3 degrees nose-up, to slow the aircraft to a speed suitable for landing (Vref).

The aircraft should pass over the threshold of the runway (piano keys) at ~50 ft RA.  Then at ~15 ft RA the flare is instigated by raising of the aircraft’s nose to an angle of ~2-5 degrees nose-up.  This attitude is maintained (held with minimal adjustments) with constant back pressure on the control column, and no trim inputs, until the main landing gear makes contact with the runway (touchdown).  At the same time the thrust levers are slowly and smoothly retarded to idle, and if done correctly, the landing gear will touchdown as the thrust levers reach idle.

The reason the thrust levers are retarded slowly is to help prevent any unwanted nose-down pitch that naturally occurs when thrust is reduced. If the thrust is cut suddenly, the nose of the aircraft has a tendency to drop. 

The duration of the flare ranges from 4-8 seconds and the flare distance, the distance that the aircraft has travelled beyond the runway threshold, is between of ~1000-2000 feet. The difference in the duration of the flare is dependent upon the aircraft’s airspeed when it crosses the runway threshold.

A common mnemonic to remember during the flare is Check/Close/Hold. Check the attitude, close the thrust levers, and hold the attitude position.

Important Point:

  • Pilots during the flare and landing are more concerned with the attitude (pitch) of the aircraft than the descent rate. If the attitude is correct, the descent rate will be within acceptable bounds.

 

Diagram 1: Runway aiming point and distances from threshold

 

Call-outs

Immediately prior to and during the flare it is important to carefully listen to the radio altitude call-outs; the speed at which these occur indicate the rate of descent.  When the twenty call-out out is heard the flare should begin, as there will be a delay between hearing the call-out out and applying the required control input to initiate the flare (which will be at 15 ft RA).  If the flare is delayed until after the twenty call-out out there is a strong possibly that the landing will have too high a descent rate.

Important Points:

  • The flare can make or break a good landing. It is important to have a thorough understanding of the concept.

  • Do not trim the aircraft when below 500 ft RA.

  • Remember, the pilot flying controls the aircraft. The aircraft does not control the pilot.

Flare Problems

A successful flare to land involves several tasks that are done almost simultaneously.  If the final approach has not gone according to plan, or the pilot is not vigilant, two problems that can occur are:

  1. If the flare attitude is too steep, or the thrust not at idle, the aircraft may go into ground effect and begin to float down the runway. Floating is to be avoided at all costs; the aircraft should be flown onto the runway.

  2. If the height that the flare is instigated is misjudged (too high) the flare distance will be prolonged leading to a possible tail strike. If on the other hand the flare is begun too low, the rate of descent will be high causing a very firm landing with possible damage to the landing gear.

In situations such as this, a go around should be carried out.

Interestingly, during the flare there is a natural tendency to pull back on the control column further than necessary.  This can be quite common with new pilots (at least initially).  Bear in mind this can easily occur and be vigilant so it does not occur.

Some pilots prolong the duration of the flare, or minimise the flare attitude in an attempt to slide the aircraft onto the runway with an almost zero descent rate (often called a greaser, slider or kiss). Whilst ego-inspiring, attempting to do this should be avoided.

Important Points:

  • An aircraft in ground effect is difficult to land, because the air pressure keeps the aircraft airborne. Eventually, the airspeed will decay to a point where the effect ceases, resulting in a heavier than normal landing.  Additionally, ground effect causes the aircraft to consume more runway length than usual.

  • Do not prolong the flare in the hope of a zero descent rate touchdown (slider) A slider style touchdown is not the criteria for a safe landing.

  • Do not prolong the flare, trim, or hold the nose wheel off the runway after landing (for example, trying to slow the aircraft because of a higher than normal airspeed), as this may lead to a tail strike.

Landing Descent Rate

A landing (touchdown) occurs when the main landing gear makes contact with the runway (not the nose wheel).  Ideally, a descent rate between ~ 60-200 ft/min is desired for passenger comfort.  This said, Boeing aircraft can tolerate reasonably high descent rates in the order of 600 ft/min.

Speaking with line pilots regarding what constitutes a hard landing will garner innumerable responses, but most agree that a hard landing is in excess of 250 ft/min.

Slider style landing can cause a shimmy to occur to the landing gear

Interestingly, a slider style landing can be detrimental to the landing gear by causing the wheels to shimmy, leading to increased wheel maintenance. This is because the landing gear is designed to land on the runway with a certain amount of inertia.  Also, a slider style landing in wet conditions can lead to aircraft skidding.  In wet and icy conditions, it is desirable to have a firm landing to aid in tyre adhesion to the runway.

If the aircraft is travelling at the correct airspeed, has the correct attitude, and the thrust levers are reduced to idle at the correct time, the aircraft will land at a reasonable descent rate.

Things to Consider (situational awareness)

During the approach and landing phase of flight, maintaining situational awareness is crucial. Pilots must be fully aware of the aircraft's altitude, and position in relation to the runway, terrain, and other aircraft in the vicinity. This level of awareness, often referred to as situational or positional awareness, is essential for safe and efficient landing operations.

 Important Point:

  • It is important to take advantage of electronic aids to assist in situational awareness. 

The following (at a minimum) is recommended to increase situational awareness:

  • Create distance rings from the runway threshold.  For example, a ring at 10 miles and a ring a 7 miles (CDU);

  • Select an appropriate approach type from the FMC (ILS, RNAV, VOR, IAN, etc);

  • Set the Navigation Display (ND) to Map mode;

  • Turn on the various navigation display aids for the ND (waypoints, station, airports, range rings, etc) by selecting them on the EFIS;

  • Select the Vertical Situation Display (VSD);

  • Display the Flight Path Vector (FPV) on the PFD by pressing FPV on the EFIS;

  • Display range rings by pressing the EFIS knob;

  • Turn on TCAS on the by pressing the TFC button on the EFIS; and,

  • Set the EFIS to terrain.

Another aid frequently forgotten about is the Vertical Bearing Indicator (VBI).  The VBI is an ideal way to determine the correct rate of descent to a known point. The VBI can be accessed from the descent page in the CDU.

Depending on the approach type selected from the FMC, the PFD will display critical information relevant to the chosen approach. The pilot can either use automation to fly the approach, or if hand flying follow the pitch and roll guidance markers. The Navigation Display (ND) in MAP mode, displays a clear overview of the aircraft's lateral and vertical position in relation to the designated navigation aids.

The information that is available is impressive, but sometimes too much information is not a good thing; a cluttered display can cause confusion and a time delay understanding the data displayed. Nearly all flight crews use the Captain and First Officer ND to display different snippets of information depending upon who is flying the aircraft and how they want to view the information.

Additional information: Approach Tools.

Control Column Movements - how much is too much

It is evident from various discussions on forums, that a number of virtual pilots do not understand how much movement of the control column is considered normal. This is exacerbated by U-Tube videos of pilots aggressively moving the yoke in real aircraft at low altitudes. Often this leads to these individuals re-calibrating their controls in flight simulator to mimic what they have seen in various videos.

Understandably, many virtual pilots have not piloted a real 737; many have flown light aircraft, however, the control movements in a light aircraft such as Cessna are completely different to those in the 737.

First, many of the U-Tube videos do not provide any input to what the crosswind and gust component was during the landings in question.  In windy conditions, control movements (that also include the rudder) may require a more heavy handed approach, however, without this information gauging technique is impossible.

Second, there are three types of individuals: those that at excel their chosen profession, those that get by, and those that should not be in the profession at all.  Which type of individual is flying the aircraft in the U-Tube videos ? If an approach is moderately unstable, and the aircraft is piloted by a below average pilot, then they may be moving the control column erratically as they try to bring the aircraft back onto station.

Many of the U-Tube videos are uploaded to generate clicks - not to teach correct technique, and erratically moving the control column may, in their mind, instill excitement that the approach is difficult but manageable. In other words, excitement brings clicks… I have not even touched upon the ‘look at what I can do’ philosophy.

Moving the control column when flying the 737 should be done smoothly, and during the approach the movements should be relatively minor with incremental adjustments to pitch and roll.  The more aggressive the movement, the more the aircraft will alter its position, requiring yet further adjustment to bring the aircraft back into line (yo-yo effect). 

If you are needing to make large movements of the control column to keep the aircraft on course (minimal crosswind), then there is a strong possibility that the calibration of the control column is not correct, or the control column has not been correctly calibrated in Windows.


Step Guide To Landing the 737-800

To Land - Summary

To land the 737-800, the general idea is to gradually slow the aircraft to an airspeed which at the beginning of the descent will, at idle thrust, enable the aircraft to descend on a 3 degree glide path to the runway.

As the airspeed decays, the flaps are extended as per the flaps extension schedule.  The thrust levers, rather than being continually adjusted, which can cause engine spooling, are set to approximately 55%N1 with the ultimate aim of airspeed not exceeding (going under) Vref+20.

At approximately 7 NM from the runway, the landing gear is lowered and flaps 15 extended.  Flaps 30 and/or flaps 40 are extended as the aircraft’s airspeed decays to Vref +5.  At this point the landing checklist is completed; the aircraft should be stabilised by 1500 ft AGL.

After crossing the runway threshold at 50 ft RA, the aircraft is flared at approximately 15 ft RA by raising the aircraft’s nose 2-5 degrees nose-up and simultaneously bringing the thrust levers to idle.

Notes:

  • This guide primarily discusses the landing of the 737-800.  A generic style approach has been ‘loosely’ used to provide context. For brevity the Initial Approach Fix (IAF) has been used to signify the descent point.

  • There are a number of ways to fly the 737 aircraft, however, the landing technique has little room for variation.

Important Points:

  • This guide assumes manual flight (hand flying). If using full or part automation, disconnect the autopilot and autothrottle at ~1500-1000 ft AGL and land manually.

  • Speed Check refers to a possible adjustment of pitch or thrust following a change in the aerodynamics of the aircraft. For example, extending flaps or lowering the landing gear.

Prior to Initial Approach Fix (IAF)

1.       Aim to be at 10,000 feet (250 kias) at 30 miles from runway.

2.      Complete initial descent briefing prior to the IAF and configure the aircraft’s avionics and instruments for the chosen approach.

  • The IAF (location, distance from runway, and altitude) is printed on the approach chart.

3.       Reduce airspeed to the flaps UP indication on the speed tape (usually approximately 210 kias) prior to reaching the IAF.

  • Reduce airspeed in level flight.

  • Bring the thrust levers to thrust idle.

  • When reaching or passing through flaps UP select flaps 1.

  • Correct flap procedure is to extend the next flap increment at, or passing through the previous flap increment.

4.       Reduce airspeed to ~190 kias and extend appropriate flaps increment as per the flaps extension schedule (usually flaps 1).

  • Note that the above airspeeds may differ slightly depending on the weight of the aircraft.

Beginning Descent

1.       Complete the approach checklist.

  • The approach chart will indicate at what point you should begin a descent.  In the absence of an approach chart, then an approximate altitude and distance to begin descent is ~ 4000-3000 feet AGL ~ 12-10 NM from the runway threshold (use rule of thumb: 3 NM/1000 ft loss in altitude).

2.      At the IAF, reduce thrust to idle (or near to) and lower the aircraft’s nose to an attitude of ~5 degrees nose-down

3. If not already at, extend flaps 5 (flaps 1 to flaps 5 jumping flaps 2). Airspeed will be approximately 190 kias.

  • Speed Check.

  • The pitch may need to be adjusted to maintain desired airspeed.

  • If the aircraft is travelling too fast, or ATC have advised to slow down, consider slowing the airspeed to ~180 kias and extending flaps 10.  If necessary, increase thrust to maintain descent rate.

  • For a step-down approach, use the same procedure as mentioned above, with the added step that you must anticipate what the aircraft will do when you level off at the end of the step-down.  At the level off, you will need to adjust pitch for level flight and probably need to increase thrust.  In both scenarios, the Flight Path Vector (FPV) can be very helpful in determining the attitude of the aircraft.

4. During the descent, try to maintain a descent rate of 600-800 ft/min

  • Do not exceed 1000 ft/min (unless a special briefing has been carried out for a non-standard approach).

5. The aircraft should descend on a 3 degree glide path

  • Use the speedbrake sparingly, especially after beginning your descent.

  • Adhere to the flaps extension schedule.  Correct management of the flaps is selecting the next lower speed as the additional drag of the flaps begins to take effect.  This minimises engine spooling and increases passenger comfort in addition to making the flaps transition smooth.

  • Anticipate what the aircraft will do when you extend the flaps.  The flaps will cause increased drag which, assuming you want to maintain the same airspeed and rate of descent, will either require a decrease in pitch or an increase in thrust.

  • During the descent, the aircraft’s airspeed will decay.  As the airspeed passes through the flap indications on the speed tape extend the next flaps increment. 

6. Do not exceed (go under) Vref +20.

  • Vref +20 is displayed as a white carrot on the speed tape (displayed after setting Vref in the CDU).

7.       As the aircraft nears the outer marker, or is ~ 8-7 NM from the runway, idle thrust should be increased to ~55%N1

  • Increasing %N1 is to counter the effect of drag from the flaps and soon to be the lowered landing gear.  Allow thrust to stabilise for a few seconds.

  • It is a balancing act (based on aircraft weight, airspeed, and drag) to what %N1 is set.  Start with 55%N1 and adjust from here. 

  • The thrust setting that has been set should be enough to compensate for the increased drag from the flaps and landing gear, however, you may need to adjust the thrust setting slightly to maintain the desired airspeed and rate of descent.  Think ahead and factor this into your pitch and thrust settings. 

8.       At the outer marker, or at ~7 NM from the runway threshold, or between 2400-2000 feet AGL, lower the landing gear

  • There is no absolute rule as to when to lower the landing gear.  The longer you delay, the less noise and fuel will be used.  I find that anywhere between 7-5 NM works well (weather dependent).

  • If you are carrying out a delayed flaps approach, then the landing gear is usually lowered at 5-4 NM.   (distance may change depending upon pilot preference and airline policy).

9.       Immediately after lowering the landing gear, extend flaps 15

  • Speed Check.

  • The drag will increase dramatically after lowering the landing gear and extending flaps 15.  Plan ahead and if necessary decrease pitch and/or increase thrust.

10.   Arm the speedbrake.

11.   Set the Missed Approach Altitude in the altitude window of the MCP.

12.   Complete the landing checklist.

Final Approach

1.       At ~ 5-4 NM from the runway threshold, and at an altitude greater than 1500 feet AGL, extend landing flaps.

  • Extend flaps 30 jumping flaps 25 unless flaps 40 is being used, in which case you would extend flaps 25.

  • Speed Check.

2.       At this point the aircraft’s airspeed will be very close to Vref +5 and the aircraft will be closing rapidly on the runway threshold.

  • Add wing/gust component if necessary to Vref +5.

3.       Raise the aircraft’s nose to an attitude of ~2.5 degrees nose-up.

4.       Decrease the aircraft’s descent rate to ~ 500-600 ft/min

  • This will aid in the transition to the flare by slightly increasing the nose-up attitude.

  • At 1500 ft RA each pilot’s deviation alerting system self tests upon becoming armed.  The test will display on the PFD an amber coloured localizer deviation that will intermittently flash for 2 seconds.

  • Depending upon airline policy, the aircraft must be stabilised between 1500-1000 ft AAE.

For example, QANTAS state that the aircraft must be stable by 1000 ft RA with a attitude pitch of 1-3 degrees nose-up.

Landing, Flare and Reverse Thrust

1.       Select a part of the runway where you want to the land (use the runway aiming markers).

2. Adjust the attitude of the aircraft so that it is aimed at this location

  • For guidance, the runway centerline should be running between your legs.

2.       As the aircraft passes over the runway threshold (piano keys), adjust your aiming point to approximately 3/4 down the runway

  • When crossing the runway threshold and beginning the flare, focus your eyes on the end of the runway and watch the horizon. This helps to gauge whether the aircraft wings are level.

3.       The height that the aircraft should be at when crossing the runway threshold is ~ 50 feet AGL.

4.       At ~15 feet RA, initiate the flare and increase the aircraft’s attitude ~ 2-3 degrees nose-up.

  • Listen for the RA call-outs. At the RA 20 call-out begin the flare (this is because by the time your brain has processed the call-out and you have moved the control column, the aircraft will be at RA 15 ft.

  • Maintain back pressure on the control column to keep the attitude constant until the aircraft’s main gear touches down.  If the flare has been done correctly, the main gear will touchdown simultaneously with the thrust levers reaching idle.

  • When initiating the flare, the increased attitude will decay the +5 kias plus any gust correction that was added to Vref. The aircraft’s main gear should touchdown at Vref.

  • During the flare smoothly bring the thrust levers to idle.  Do not suddenly chop the thrust.

5.       Ideally the aircraft’s descent rate, when landing, will be 200 ft/min or less.

6.       Lower the nose wheel without delay by smoothly flying the nose wheel onto the runway. 

  • Control column movement forward of neutral should not be required.

7.       Engage reverse thrust and check that spoilers have engaged. 

8.       Verify that speedbrake lever is down.

9.       Disarm the auto brakes as the aircraft approaches 60 knots ground speed.

10.   Approaching 60 knots ground speed, and only after hearing the 60 knots call, begin to slowly retard reverse thrust.

  • The reversers should be at reverse idle as you reach taxi speed.  Maintain reverse idle for a few seconds to enable the reverse thrust to fully dissipate.  Close and stow the reversers.

11.   Apply manual braking as required.

Important Points:

  • Below ~ 200 feet AGL the landing is primarily visual.

  • To assist in gauging the flare, focus your eyes nearer to the end of the runway and watch the horizon (which should be horizontal).

  • A go around (TOGA) can be instigated at anytime prior to landing touchdown.

Final Call

Although approach types differ, the technique of landing the 737 is identical in each approach.  By far the most critical elements of a successful approach and landing are speed management, extending the flaps on schedule, thrust settings and using the correct attitude during the flare. Despite a number of variables occurring in quick succession, with experience, you can easily maintain a constant speed, attitude and descent rate as you fly down the 3 degree glide path.

Related Articles

Glossary

  • AFE – Above Field Elevation

  • AGL – Above Ground Level

  • Attitude – Synonymous with pitch.  The angle that airflow hits the wing. 

  • DFA – Delayed Flap Approach

  • DH (A) – Decision Height (or Decision Altitude). If not visual, the approach cannot continue (Precision Approach)

  • EFIS – Electronic Flight Instrument System

  • ILS – Instrument Landing System

  • IMC – Instrument Meteorological Conditions

  • KIAS – Knots Indicated Airspeed

  • MAP – Map display (forms part of Navigation Display)

  • MAA - Missed Approach Altitude

  • MDA - Minimum Decent Altitude. If not visual, the aircraft cannot descend lower than this altitude (Non Precision Approach)

  • ND – Navigation Display

  • NM - Nautical Miles

  • PFD - Primary Flight Display

  • Pitch – Synonymous with attitude.  The direction of the aircraft relative to the horizon.

  • RA – Radio Altitude

  • VMC – Visual Meteorological Conditions

  •  ~ Symbol for approximate 

Updating Magnetic Declination in MSFS-2020

Sometimes, the aircraft during an approach does not correctly align with the runway heading published on the approach chart. This can lead to a RW/APP CRS Error to be displayed on the FMA.

Before exploring scenery, navigational database and add-on inconsistencies, the problem may be that the magnetic declination in flight simulator is not correct for the runway or scenery being used.

The magnetic declination forms part of the database table that relates to any scenery (and airport runway) used in flight simulator.

I have written about magnetic declination in two earlier articles, however, these articles related to FS9 and FSX and not MSFS-2020.

Magnetic Declination

Simply explained, magnetic north is the direction that the north end of a compass needle points, which corresponds to the direction of the Earth's magnetic field. True north is the direction along a meridian towards the geographic North Pole. The magnetic declination (also called magnetic variation) is the angle measured between true north and magnetic north.  This distance changes annually and is one of the reasons that a topographic map has a declination table printed in the margin. Without a declination table, the map would soon become inaccurate.  To calculate the magnetic declination the map user, depending upon their position, would add or subtract the declination from the bearing to obtain an accurate bearing to plot a course.

Flight Simulator

The magnetic declination used by flight simulator is stored in a .bgl file named magdec.bgl. This file is usually located in the simulator’s scenery database.  The file is accurate at the time of development, but if not updated regularly will be incorrect for today’s date.

You would expect magnetic declination errors with flight simulator platforms such as FS9, FSX and earlier versions of P3d; after all, they were released several years ago, but deviation errors are also seen in MSFS-2020.  The reason for this is that Microsoft did not compile a new magnetic declination table when the scenery was developed; rather, they used the existing table from FSX.  The exception being for some of Asobo’s airports which probably do have up-to-date declination.  

Considering that MSFS-2020 is automatically updated, it would have been a relatively easy task to also update the magnetic declination (perhaps in the future).

Updating Magnetic Declination

Updating the declination for MSFS-2020 involves replacing the magdec.bgl file with an updated file.

This file can be downloaded free of charge from Herve Sor’s website (the .bgl file is regularly rewritten to reflect declination changes).  Be sure to read the accompanying Read Me file for further information.

Locating the .bgl file (MSFS-2020)

The magdec.bgl file is located in the following directory: 

  • C:\Users\LOGINNAME\AppData\Local\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\ LocalCache\Packages\Official\OneStore\FS-base\Scenery\Base\Scenery

Note that if you have done a custom install of MSFS-2020 to a different drive, then the folder structure should represent the location you have installed the software.

If using Steam, the folder structure is:

  • C:\Steam\Steamapps\Common\MicrosoftFlightSimulator\Official\OneStore\fs-base\Scenery\Base\Scenery\

Installing the .bgl file

Find and open the scenery folder.  Prior to changing anything, always make a backup of the existing magdec.bgl file.  Be sure to remove the .bgl file extension.  I would suggest renaming the file to magdec_backup_original.  This enables you, if necessary, to easily roll back the file (after changing the file name back to the original name).  The backup file can either remain in the folder or be removed to another location for safe keeping.  Next, copy and paste the new magdec.bgl file to the folder.  When you open flight simulator the magnetic declination table will be rebuilt during the start-up process. This may take a few minutes.

Important Point:

  • After downloading the zip file from Herve’s website, open and read the Read Me file which provides additional information.

Other Simulator Platforms

To update the magnetic declination for other simulation platforms, ensure you download the correct updated magdec.bgl file for the simulator being used.  The installation route is usually the Scenery/Base/Scenery folder.

Magnetic declination is important. The declination information for the approach chart and the simulator must be identical

Do I Need To Update ?

The flight simulator can only reproduce accurate navigation based on the quality of the installed database. If you are using Navigraph data and your simulator’s declination is not correct, a corresponding error will occur between Navigraph and the scenery in the simulator.

If you use an approach chart, the magnetic declination record between the chart and the simulator must be identical; otherwise, the approach course will be inaccurate (landing left or right of runway).  Likewise, if you are using Lateral and Vertical Navigation (LNAV and VNAV) and have the incorrect declination, the aircraft will not fly the correct course during an automated approach (for example an RNAV approach).

The update is a very simple process and takes but a few minutes and it is strongly recommended.

Final Call

Magnetic declination is a critical factor to consider, before investigating other potential causes for navigational discrepancies. To ensure accurate navigation ensure the magdec.bgl file is up-to-date.

Glossary

  • FMA - Flight Mode Annunciator.

New Website. Complete Overhaul of Flaps 2 Approach

The previous website has been replaced with a new website.

This has occurred because the server company (SquareSpace) that hosts the website announced limited support for their legacy software.  As a result, I have had to redesign and restructure every web page on the site to bring them into line with the new system and current technology.

The original website, developed in 2011, was initially meant to be a ‘Dear Diary’ - a medium in which I could record the how or why I did something.  However, over the years the site has become more comprehensive.

In the process of rebuilding the site, I have removed several articles that are not relevant today. I also have edited some of the articles to bring them into line with current operational procedures. This process of updating older articles will continue as technology and procedures change.

  • As you peruse the site you may notice that some of the images on the journal posts may appear pixelated or cannot be enlarged. This will be resolved. Bear in mind it takes many DAYS to prepare images, upload, and re-write journal posts so that they fit within the new system.

To maintain consistency with the old site, I have attempted to retain the original site design and colours as much as possible.  I have also tried to streamline the design in such a way that the site is easy to navigate and doesn’t appear too cluttered.

The cost to maintain this website is not cheap. By choosing not to have advertising means you have a more pleasant reading experience, and it costs me more money. If you find the information helpful and want to help cover the server and hosting cost, please use the PayPal donate button.

I have little doubt there will be some ‘teething’ issues as I learn the new system. If something doesn’t work as expected, be assured that it will be rectified.

I hope you enjoy the new site.

Scale ID Annunciation (RW/APP CRS Error)

Scale ID Annunciation display in upper left hand corner of the Primary Flight Display

The Scale ID annunciation (often called the approach reference), displayed in the upper left of the Primary Flight Display (PFD), is one of a suite of displays that comprise the PFD Navigation Performance Scales (NPS) Indications. 

In the image a runway approach course error (RW/APP CRS Error) is being displayed.  The airport is Hobart, Tasmania and the ILS approach is to runway 12.  The error has been generated because the CRS window in the MCP has the incorrect approach course (140 degrees).  If the approach course was correct, the display would be coloured white - not amber with a strike-through line.

The Scale ID Annunciation display provides, the for the selected approach type, the following approach reference information:

  • Airport identifier;

  • Runway approach course;

  • Distance to the runway threshold; and,

  • Approach type.

The display also indicates whether a runway approach course error (RW/APP CRS) has occurred.

Possible approach type displays include:

  • LNAV/VNAV (LNAV and VNAV deviations).

  • LOC/VNAV (Localiser with VNAV deviation).

  • FAC/VNAV (IAN final approach course with VNAV deviation).

  • LNAV/G/S (LNAV deviation and glideslope).

  • LNAV G/P (LNAV deviation with IAN glidepath).

  • ILS (ILS approach).

  • FMC (IAN approach).

  • GLS (GLS approach).

Airport Identifier and Display Colour

The airport identifier comprises the identifier and airport name (abbreviated).  The identifier will change depending upon the approach type.  For an ILS (and IAN approach) the identifier will be the letter I followed by the airport abbreviation.  For example, Hobart airport is YMHB.  In this case for an ILS approach the airport identifier will be IHB.

The identifier is displayed in two colours: white and amber; amber being cautionary.  The later also incorporates a strike-through line (this line dissects the airport identifier and approach course).

White indicates that all the parameters required for the approach have been completed correctly.  An amber colour/strike-through indicates that one or more of the required parameters have not been met.

Colour Combinations

The following colour combinations can be observed (further information is discussed later in the article). 

  • Frequency and approach course displayed in white:

When the navigation radio is tuned to the ILS frequency, the identifier will initially display the ILS frequency (109.90) for the approach.  The frequency will then change to display the airport identifier (IHB).  Whether the colour displayed remains white or changes to amber will depend on whether both navigation radios and CRS course windows are set to the correct ILS approach.

If either display is coloured amber it indicates a RW/APP CRS error has occurred.

  • Airport Identifier displayed in amber:

One navigation radio is tuned to the ILS frequency.  Tuning the second radio to the same frequency will cause the display to change from amber to white.

  • Approach course displayed in amber:

One or both courses in the CRS course windows (MCP) is not set to the correct ILS approach course.

  • DME and approach type:

The DME and approach type (ILS) are always displayed in white.  The DME will display the distance to the runway when the glideslope is captured by the aircraft.

Pre-Approach Tasks

Prior to commencing an approach, the following should be carried out:

  • The correct frequency entered into to the navigation radios (NAV 1 & NAV 2);

  • The correct approach course (for the runway selected) entered into the Captain and First Officer side CRS course windows in the MCP;

  • An appropriate approach selected from the FMS database (depends on the approach type being used); and,

  • The approach course for the runway entered into the heading window in the MCP.

Delay

The logic controlling the scale ID annunciation periodically interrogates that data entered into the navigation radios and MCP.  This means that a delay is often observed between the annunciation changing colour from white to amber or back again.  I am unsure of the timing.

Discussion

The indication that a RW/AP CRS error has been triggered doesn’t alwasy preclude an approach from being carried out (although it’s not recommended).  The annunciation indicates that, for the selected approach, something hasn’t been completed with regard to the configuration of the avionics.  It's rarely the case that the frequency hasn't been correctly entered into to the navigation radio; more often than not the cause of the annunciation is a CRS course discrepancy, or failure to configure the second navigation radio to the same frequency as the controlling navigation radio.   

Using the ILS approach as an example.  To correctly configure the instruments for an ILS approach and not receive a cautionary warning, the following must be completed:

  • Enter the correct ILS frequency into the BOTH navigation radios; and

  • Enter the correct approach course into BOTH the CRS course windows in the MCP.

It’s also recommended, but not mandatory to:

  • Enter the approach course into the heading window in the MCP; and

  • Enter an appropriate approach into the CDU/FMC.

If you enter the ILS frequency into the controlling navigation radio, and enter a different frequency into the other navigation radio, an amber-coloured RW/APP CRS annunciation will be generated.  Likewise, a caution will occur if the Captain-side and First Officer side CRS windows don’t display the identical ILS approach course.

IMAGE A-1: ILS approach into runway 12 for Hobart, Tasmania (IHB).  The approach course for this approach is 120 degrees.  The controlling navigation radio (Captain-side/not shown) has been set to the correct ILS frequency (109.90).  The heading that the aircraft is flying is 120 degrees, and the compass rose is offset to the course direction that is displayed in the Captain-side CRS window (140 degrees)

Example (Hobart, Tasmania IHB)

Image A-1 shows an ILS approach into runway 12 for Hobart, Tasmania (IHB).  The approach course for this approach is 120 degrees.  The controlling navigation radio (Captain-side/not shown) has been set to the correct ILS frequency (109.90).  The heading that the aircraft is flying is 120 degrees, and the compass rose is offset to the course direction that is displayed in the Captain-side CRS window (140 degrees).

In the example, a RW/APP CRS annunciation has been triggered for an ILS approach.  The airport identifier and approach course are coloured amber with a strike-through line.   The DME is 9.4 miles and is coloured white (correct data).

This approach can be flown despite the discrepancy between the four courses (120, 180, 130 & 140 degrees) and a RW/APP CRS annunciation.  This is because the ILS approach course (120 degrees) is coupled to the ILS frequency set in the controlling navigation radio  – not the course as indicated in the CRS windows in the MCP. 

In the example you can see that the localiser has been captured (this is identified by the magenta-coloured course deviation line being centered/in-line with the course pointer) despite the CRS window displaying a course of 140 degrees.  Once the aircraft has captured the localizer it will fly the localiser heading no matter what course is displayed in the CRS window (provided it does not exceed 90 degrees).

While this example holds true for an ILS approach other approach types may behave differently.

Important Points:

  • The scale ID annunciation is an amber-coloured display that annunciates when the avionics have not been correctly configured for the selected approach.  The display is a cautionary.

  • The approach cannot be flown If the CRS course discrepancy is greater than 90 degrees from the ILS approach course.  This is because the aircraft will follow the direction of the course set in the CRS window (if greater than 90 degrees).

ProSim-TS

The ProSim737 avionics suite replicates the RW/APP CRS logic used in the real aircraft. 

Database Inconsistencies

In some instances the annunciation is displayed despite entering the correct information.  A possible reason for this is a scenery navigation database inconsistency. 

In older scenery designs the physical location of the localiser beacons was part of the scenery file and this information is what the simulator referred to.  With the advent of up-to-date navigational points (supplied by Navigraph) the simulator now refers to a navigational database rather than a scenery database.  An inconsistency will occur if there is a discrepancy between the location of the localiser beacons in the scenery and the information recorded in the navigational database.

Final Call

The RW/APP CRS annunciation, although confusing to the uninitiated, does not necessarily mean that an approach cannot be carried out.  However, it’s prudent before flying the approach to understand why the RW/APP CRS error has been displayed. 

In more cases than not, the reason for the cautionary annunciation is a failure to configure the navigation radios to the same frequency and/or enter the same ILS approach course into both the CRS course windows in the MCP.

Batch Files to Open and Close Flight Simulator

Opening and closing the various files and ancillary programs to operate a flight simulator can be onerous and time consuming.  While there have been several programs released that enable you to launch flight simulator with a press of a key, they seldom work with complicated platforms such as flight decks. 

One of the most commonly used methods to open files and programs is to use the start menu within Windows.  However, this is not without it’s shortcomings, and specialist knowledge is required.  An easy and trouble free approach is to use batch files.

What is a Batch File

A batch file is a script file that stores commands to be executed in a serial order.  It helps automate routine tasks without requiring user input or intervention. Some common applications of batch files include loading programs, running multiple processes or performing repetitive actions in a sequence in the system.

Also known as a batch job, a batch file is a text file created in Notepad or some other text editor.  A batch file bundles or packages a set of commands into a single file in serial order.  Without a batch file these commands would have to be presented one at a time to the system from a keyboard.

Usually, a batch file is created for command sequences when a user has a repetitive need.  A command-line interpreter takes the file as an input and executes the commands in the given order.  A batch file eliminates the need to retype commands, which saves the user time and helps to avoid mistakes.  It is also useful to simplify complex processes.

Windows usually uses the .bat extension for batch files.

Whilst there are several methods that can be used to write a batch file, I have found that the examples below operate flawlessly.

Writing a Batch File

It's a simple process to write a batch file. 

Prior to beginning, it’s wise to think about the order you want the programs to open, and whether you want a pause between opening particular files and programs.  While a pause is probably not necessary, it’s a good idea as it allows a file or program to complete its opening sequence, prior to the next file or program opening.

When you have completed writing the batch file in notepad save the file with a .bat extension.  To test the batch file double click on the saved .bat extension.

Although others will disagree, I always open the MSFS-2020 or P3d and allow the program to settle before opening any batch file or other programs.

The following examples of batch files are user-specific.  You will need to substitute the file structure with the file structure you are using.

Opening Files and Programs

  • An example of a batch file to open the main flight simulator computer (server).

@Echo  off

//Alpha Main Server Computer (ALPHA-SERVER-P3)  - 09:38 - 25/08/2023

//ProSim738 V3

//ProSim Ancillary Programs

start /d "D:\Flight Simulator Files\SimStacks October 2021\SimStackSwitchv702" Switch.jar

Timeout 0.5

start /d "D:\Flight Simulator Files\FS Set Volume" FSSetvol.exe

Timeout 0.5

start /d "D:\Flight Simulator Files\SimSounds 4.0" SimSounds.exe

Timeout 1

start /d "D:\REX WeatherForce.exe

//ProSim Main Programs

start /d "D:\Flight Simulator Files\ProSim738 V3\ProSimAudio" ProsimAudio.exe

Timeout 1

start /d "D:\Flight Simulator Files\ProSim738 V3\ProSimB738" ProSimB738.exe

An example of a batch file to open the avionics suite on the second computer (client 1).

@Echo off

//Client 1 - ProSim-AR B738 Avionics Suite V3    14:07 5/09/20

//PS738 V3

//Ancillary Programs

start /d "C:\Users\user name\Documents\FSF\Programs\MSFS WideFS7" kilo

start /d "C:\Users\user name\Documents\FSF\Programs\Landing Rate Monitor" LRM.exe

start /d "C:\Users\user name\Documents\FSF\Programs\SimSounds 4.0" SimSounds.exe

//Hardware Connector

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\ProSimB738-HardwareConnector" ProSimB738-HardwareConnector.exe

//ProSim737 Displays and Indicators

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\Displays\CAPT PFD" ProsimDisplay.exe

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\Displays\CAPT ND" ProsimDisplay.exe

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\Displays\FO PFD" ProsimDisplay.exe

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\Displays\FO ND" ProsimDisplay.ex

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\Displays\EICAS" ProsimDisplay.exe

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\Displays\FLAPS" ProsimDisplay.exe

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\PS738ChronoCaptain" ProsimDisplay.exe

Timeout 3

start /d "C:\Users\user name\Documents\FSF\ProSim738 V3\ProSimIOS" ProSimIOS.exe

Closing Files and Programs

Likewise, you can also use a batch file to close files and programs sequentially or simultaneously (kill all).

An example of a batch file used to close programs on the main flight simulation computer (server).

@Echo off

//Alpha Main Server Computer (ALPHA-SERVER-P3)  - 09:38 - 25/08/2023

//ProSim738 V3 – closure batch

taskkill /IM wideclient.exe

Timeout  2

taskkill /IM ProSimAudio.exe

Timeout  1

taskkill /IM PMSounds.exe

Timeout 1

taskkill /IM Prosim737.exe

Timeout  4

taskkill /IM fs2020.exe

  • im specifies the image name of the process to be terminated (for example, PMSounds.exe or ProSim737.exe).

  • @echo on/off defines whether a name or message will be displayed on the console.  It’s also used for other tasks such a script troubleshooting.  I have used it in my batch files because I was told it was a good idea to do so, but if you don’t use the @echo command the batch file still works.  If you do use the @echo command I recommend you use @echo off as this will turn off this feature.

  • The // syntax is used to stop the line from being read by the batch file. 

In the examples, the Taskkill command has been used to close the programs.  Taskkill will cause the program to terminate gracefully, asking for confirmation if there are unsaved changes.

To forcefully kill a process, add the /F option to the command line. Be careful with the /F option as it will terminate all matching processes without confirmation.

An example using the /F command is: Taskkill /F /IM ProSimAudio.exe.

There is debate in the computer community to the validity of closing files and programs simultaneously, as ‘killing a program’ may not allow the program enough time to save information it may be saving during the closure process.

For this reason, I'm hesitant to close flight simulator (or other programs) using a closure batch file without a timeout or delay sequence.  Needless to say, it's an easy process to configure a time delay into a batch file to create a delay before closing each program.

Timeouts

Depending upon your computer specifications, some programs may open and close at differing speeds.  If you want a program is open or close before the next program, then a delay sequence will need to be timed into your batch file. 

The timeout command is used to trigger a delay between the programs, enabling any read/write requirements to occur prior to the next program beginning it closure routine.  The numeral denotes seconds or part thereof. 

Streamlining

Once you have created and saved the batch file, a suggestion is to create a shortcut to the file.  Doing this will enable you to make changes to the batch file such as how the file is executed (minimised or maximised), the position on the screen, colour and font style used, and whether to use an icon for easy identification.  Additionally, by creating a shortcut it enables you to place the shortcut on your task bar.

To create a shortcut, right click the batch file and save as a shortcut.

Using Batch Files and ProSim IOS

ProSim-TS IOS screen in opened to network page.  Rather than explain everything, copy the details and use trial and error to achieve your desired result

If you are using multiple computers, you may want to use the ProSim Instructor Operator Station (IOS) to trigger the opening or closure of programs (via the batch file).  When IOS is configured correctly, you will be able to open and close a batch file on one or more networked computers from one computer screen.

To configure IOS, open the network tab, select add a new action or type and select start program.  In the path to executable file on client box type the file address of the batch opening file.  Choose the start option you prefer and ensure that enabled in checked.

To close your programs, open a second action and type in to the path to executable on client box the file address of the batch closure file.

The accompanying image should be self explanatory.

There are other ways to do this, however, this method is probably the simplest.

Caveat

I am not computer technician.  I have used batch files similar to the examples shown for many years without issues.

Final Call

Batch files are but one way to minimise workload and automate the opening and closure of ancillary programs that are used with flight simulator.  The use of IOS to trigger batch files also enables the user to open and close ancillary programs from the one computer screen (instructor station).

Updating ProSim-AR Visual Flight Model (VFM) Without Loosing Configuration Data

Updating ProSim-AR Visual Flight Model (VFM) Without Loosing Configuration Data

ProSim-AR produces a dedicated visual flight model (VFM) that can be used with ProSim737.  The VFM reflects the aerodynamics and flight parameters of the real-world Boeing 737 in addition, to displaying a visual representation of the aircraft in a selected number of real-world airline liveries.

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Commercial Rotary-String Potentiometer Review

Commercial Rotary-String Potentiometer Review

Recently, whilst on a final approach I heard a ‘twang’ followed by loss of aileron control.  I knew immediately what had happened; the tensioned stainless steel string from the string potentiometer had snapped and the wire had retracted into the mechanism. 

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Changing Sound in the ProSim 737 Aircraft with MSFS-2020

Many enthusiasts like to change the sound files that come with ProSim-TS 737 aircraft.  In my simulator I use an assortment of sounds including those from ProSim, PMDG, the immersion CFM engine sound pack, and audio recordings that have been made from the real aircraft.

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ProSim737 IOS - Unconventional Settings

The user interface in the Instructor Operator Station (IOS) allows the user to customise several functions, in addition to enabling or disabling specific options.  Whilst most of the functions are straightforward, there are several options that are unconventional and therefore, probably not clearly understood.

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Switch-mode Power Supplies

Upper unit is a MeanWell switch-mode power supply with internal cooling fan.  The lower unit is a generic Chinese made power supply with no internal cooling fan; ventilation is provided by the perforated outer case and by inclusion of an internal aluminium heat sink.  Note that the MeanWell power supply has easier access to the terminals and is much thinner in depth than the lower unit

Every simulator needs some type of power supply, whether it be a converted multi-volt computer power supply, a plug in the wall type power pack, or a dedicated set voltage AC/DC switching power supply.  I dare say that most flight simulators have an assortment of different types that convert 240/110 Volts AC power to DC power at a specific wattage and amperage.

In this article, I will discuss switching power supplies (switch-mode).  I will also very briefly address how to measure amperage using a multimeter.

Switch-mode Power Supplies

There are many types of power supplies.  However, for the most part a switch-mode power supply is the most versatile.

A switch-mode power supply is an electronic power supply that incorporates a switching regulator to convert electrical power efficiently from a higher AC voltage to a lower specified lower DC voltage.   This is done by converting the incoming mains power into a frequency between 20-kHz to 500-kHz AC that is then stepped down to a lower voltage (using a small integrated transformer).  The voltage is then rectified, filtered and regulated.

Clean Power

Clean power refers to power that is filtered and regulated, meaning the power is clean and is regulated to a predefined voltage.   This is important in the simulator environment because many interface cards and OEM components do not tolerate inconsistent voltage which can easily be the cause of inconsistent operation and USB disconnects.

In general,  a less expensive power supply will generate unclean power.

Power Supply Selection

Several companies produce power supplies – most of them are manufactured in China.  However, one company that stands out from the many is MeanWell (MW).  MeanWell is a Taiwanese company (not Chinese) that is a leading manufacturer of power supplies, and their switch-mode power supplies provide many advantages to the flight simulator builder.

Some of the advantages of using MeanWell power supplies are summarised below:

  • Constant source of clean power rated at 20% above the certification provided.  What this means is that if you run the power supply at 100% it has a further 20% before the unit will be damaged.

  • Protection from short circuit, overload and over voltage.

  • Fixed switching at 25 kHz (produces a cleaner and better regulated power).

  • Two or three year replacement warranty (model dependent).

  • Internal cooling fan (model dependent).  Fan opersation is temperature controlled.

  • Audible alarm that sounds if operating temperature is exceeded (model dependent).

  • Adjustable voltage (the voltage can be manually adjusted up or down (-+) to ensure correct voltage).

  • Wide range of operating conditions (-25 Celsius to 70 Celsius).

  • Solid enclosure with perforated holes (efficient heat sink and cooling).

  • Easy screw attachment point or ability to use a rail system.

How Many Power Supplies Do I Need ?

This is a difficult question to answer as every simulator platform is different. 

The most effective way to determine the number and size of each power supply is to calculate the amperage draw of the items that will be connected to the power supply.  Armed with this information, you can decide what power supply and amperage is needed.

A flight simulator will usually require switch-mode power supplies in 5, 12 and 28 volts of varying amperages, and the cost of each unit will increase as the amperage rating increases.

While it’s possible to wire a number of lower amperage rated power supplies together, I believe using two or three individual larger amperage units is better than several smaller amperage units.

Amperage Draw and Calculating Amperage

Every item that draws power uses amperage, and the amount of amperage necessary for the component to operate must be calculated prior to selecting a power supply of a set amperage.   Using a power supply that is over-rated, in other words has more amperage than is necessary for a given situation is not a problem, however, using a power supply that does not have enough amperage for the attached device will result in either partial or complete failure of the connected device (for example, a bulb or LED may not illuminate to full intensity).

Amperage is the strength of electricity flowing through a circuit, usually from positive to negative.

To calculate amperage draw for a specific component, for example a 5 volt bulb, you will require a multimeter that has the capacity to read amperage.

There are several U-Tube videos on the Internet that provide guidance in how to use a multimeter to read amperage, so I will not replicate what is available.  

To begin, the mulimeter's red wire from is placed into the AMP outlet and the black lead is placed into the COM outlet of the multimeter. 

You then break the closed circuit of the Korry by removing the Korry from its holder.  You connect the red wire (AMP) from the multimeter to the positive side of the Korry.  The black wire (COM) is attached to the connector (holder) that the Korry was removed from. 

Essentially you are closing the circuit with the multimeter in-line.  Make sure the multimeter is set to read amperage (A).  Then turn on the DC power to the Korry.  The multimeter will read the amperage draw when the Korry is illuminated.

Important Point:

  • Prior to connecting the wires from the multimeter, check that the fuse (usually 10 amps) is functioning inside the multimeter.   If you have a blown fuse and connect power to the multimeter, you may damage the device’s internal components.  Every multimeter is slightly different, therefore, consult the operating manual    

Rather than duplicate what already has been done, below are three links to U-Tube videos that explain how to use a multimeter to measure amperage. 

Installation of Switch-mode Power Supplies

An advantage of using the same type/brand of power supply is the ease in mounting the power supplies.  Most power supplies have a number of screw holes that enable the unit to be screwed to a prefabricated bracket, or mounted to a solid board; some can also be attached to a rail system.

My Simulator Set-Up

In my simulator, I have installed what is called a Power Supply Rack (PSR) which is located forward of the Main Instrument Panel (MIP) on the platform floor. 

The rack is essentially an open frame L-shaped bracket made from wood (nothing fancy).  To this the power supplies are mounted.  The individual power supplies are wired together in parallel (wire connects between positive terminals on each power supply) to enable connection to the mains power by one power cable.

The open frame L-bracket has several advantages: all the power supply units are located in the one location, it’s straightforward to add another power supply as needed, and an open frame structure enables good ventilation and airflow; power supplies when operated for an extended period of time can generate considerable heat.

Present on all power supplies is the voltage regulator.  This enables the outgoing voltage to be adjusted, usually to a few volts either side of the advertised voltage.  Also note the barriers between each of the terminals and the nomenclature marking above each of the terminals

Safety

Switch-mode power supplies usually have at the end of the unit a terminal bar.  The incoming mains power (three wires) is connected to the two AC and Earth terminals.  Directly adjacent are four or six terminals marked +V and -V (outgoing).   This is where you connect the +- wires from your device.  The two AC terminals (incoming) when connected to mains power are always LIVE; touching these terminals will cause a life-threatening electric shock.  Therefore, it’s paramount that these terminals are covered.

Some power supplies come with a plastic protective cover that is clipped in place after the wires are connected; all have plastic barriers between each terminal to minimise the accidental touching of wires. 

If the power supply does not have a cover, one can easily be made using a piece of plastic and held in place by electrical tape.  Clear silicon or hot glue can also be used to cover the AC and Earth terminals; the advantage of hot glue being that it’s easily removed by applying 80% alcohol.  At the minimum, red-coloured electrical tape should be used to tape over the terminals.

Safety is important when working around 240/110 volts AC and strict protocols should be followed at all times.  If in doubt, always disconnect the power supply from the mains power prior to doing any maintenance.

Single circuit busbar and multiple circuit terminal bar

Power Distribution (busbars and terminal blocks)

Any flight simulator requires various voltages to function.  For example, backlighting requires 5 volts DC while OEM annunciators (Korrys) require 28 volts DC. 

Power distribution, depending upon your skill level, can become quite elaborate and complicated, but at its simplest level is the use of busbars and terminal blocks.

Busbars and terminal block appear similar, however, are used for differing applications.

The main difference is that a busbar gathers multiple wires together for power distribution in a single circuit (one voltage).  In contrast, a terminal block has separate circuits where each wire is paired with an outgoing wire.  A simple way to think about it is, that a busbar is a single circuit whereby a terminal block is multiple circuits. 

There are as many manufacturers as there are types of busbars available;  it's also relatively straight forward to convert an inexpensive terminal bar into a busbar by routing the power wire between each terminal/circuit (the wires look like the letter U between each of the circuits/terminals).  Doing this enables one terminal to be allocated to incoming power (for example 5 Volts) rather than an incoming power wire being connected to each circuit.

Importantly, when wiring busbars or other items care must be taken to the gauge of wire used.  You don't want to use a thin piece of wire (minimal number of wire strands) when connecting to a high amperage item.  If you do, the wires will become very warm and the amperage that travels through the wire will drop (which may cause inconsistent operation or a USB dropout - if the wired item is connected to the computer by a USB cable).  A worse case scenario is the wire will melt and a fire may occur.

Blue Sea Systems busbar with transparent cover

My Simulator Set-Up

In my simulator, installed behind the Main Instrument Panel (MIP) is a small shelf on which three heavy duty high amperage busbars are mounted (5, 12 and 28 volts respectively).  Each busbar connects directly to various components. 

A further 5 and 12 volt busbar has been installed to the inside of the center pedestal, and these busbars provide 5 and 12 volt power to OEM panels, Belkin USB hubs and an Ethernet switch. 

Additional 5 and 12 volt busbars are located within the Throttle Communication Module (TCM); a small box mounted to the forward firewall of the throttle quadrant.

For the most part, I have used marine-grade busbars manufactured by Blue Sea Systems (an American company).  Although the clear acrylic covers are not necessary, they do minimise the chance of a short circuit occurring should something drop onto the busbar.

Dedicated Power Supply to Specific Aircraft Systems

It is preferable to dedicate individual power supplies to specific aircraft systems.

The advantage of linking a dedicated power supply to a particular aircraft system, is if a catastrophic failure should occur, the problem will be maintained within that system and any power leakage/spike will not be able to travel to other systems (located on a separate power supply). 

A further benefit is that the amperage draw for each power supply can be easily measured to ensure it doesn't exceed 80% of the total draw available.  Effectively, this should increase the longevity of each power supply as it will not be operating at full output. 

Troubleshooting is also easier when you know what functions are connected to each power supply.

Operating OEM components requires a relatively high amperage draw, and whilst it's feasible to 'piggy back' two power supplies of the same amperage to effectively double your amperage, this is not advisable. 

Maintenance

In general, power supplies do not require maintenance.  However, depending upon the working environment, dust can build-up on the internal workings of the unit.  If dust does build up, the unit should be routinely cleaned with a small vacuum cleaner or lint free cloth – this is especially so for those units that have an internally-driven fan which can ingest dust particles.  If a ‘thick’ layer of dust is allowed to accumulate, there is a chance that the unit may operate at a slightly higher temperature, thereby minimising service life, and perhaps altering voltage output.

Final Call

There are several types of power supplies that can be used to power components in a flight simulator; the most versatile are switch-mode power supplies.  MeanWell, a Taiwanese company, manufactures a number of switch-mode power supplies that in many ways are superior to its competition.  However, prior to using any power supply the total amperage draw of the simulator’s components should be calculated to ensure that the most appropriate switch-mode power supply is used.

Using The Tiller To Taxi The Boeing 737

captain-side steering tiller

To taxi an aircraft around the airport the pilot uses either the rudder pedals and/or a steering wheel device called a tiller.  The half-moon shaped tiller is mounted to the sidewall of the flight deck.  The number of tillers in an aircraft is not standard; some aircraft have one tiller while some have two.  The tiller controls the lateral movement of the aircraft’s nose wheel, located below and behind the flight deck.

The rudder pedals when pressed do provide some lateral movement, however, nose wheel steering is no more than 7 degrees.  To enable full lateral movement of the nose wheel  requires using the tiller with some forward thrust (called break-away thrust) from the aircraft’s engines.   

If the aircraft is to be moved backwards (for example from the ramp), then a push-back truck and ground controller is required.  The controller will connect a bar from the push-back truck to the main coupling of the nose wheel to lock the nose wheel in the forward position.  Once this is done, the push-back truck will lift the nose wheel enabling the aircraft to be reversed backwards.  A push-back truck can also be used to pull the aircraft forwards.

The ground controller will be in communication with the pilot and will instruct the pilot when it is safe to release the parking brake or start the engines (it is the responsibility of the ground controller, amongst other things, to check that the doors are closed and that personnel are clear of the aircraft).  Prior to the aircraft being moved, the pilot will speak with Air Traffic Control to obtain starting and push-back approval.

After ATC has given clearance, the pilot will:

  1. Check and cross check the taxi route instructions issued by ATC.

  2. Release the parking brake by pressing the upper section of the toe brakes.

  3. Apply forward thrust by advancing both thrust levers to around 32%.  The actual percentage N1 depends on the weight of the aircraft.  The forward thrust should not exceed 40%N1.

  4. Use the tiller to maneuver the aircraft.

  5. To stop the aircraft the thrust levers are brought back to idle, the toe brakes are pressed to stop any forward movement of the aircraft, and the parking brake applied.

Although not recommended, it is possible to aid in the turn by applying appropriate thrust only to one engine.

Important Points:

  • Reverse thrust should not be used to move the aircraft backwards primarily because of the likelihood on ingesting foreign material into the engine.

  • Whenever the aircraft is at a standstill the parking brake should be applied.

Taxi Speeds

Taxi speeds vary.  Generally, in good conditions the maximum permissible speeds are:

  • 10 knots – when doing turns;

  • 30 knots – when traveling in a straight-line along a runway;

  • 50 knots – when back-tracking along a runway; and,

  • If the runway is contaminated (ice, snow, etc) the taxi speeds are reduced to 5 knots.

How To Taxi

The nose wheel is located under and to the rear of the flight deck.  Therefore, to turn onto and follow the taxi lines accurately you must slightly overshoot the line prior to turning.

OEM Tiller

Another article addresses how to convert an OEM tiller and use in ProSim737 -  OEM tiller in ProSim737.

Final Call

With a little practice taxing the aircraft in the flight simulator is straightforward.  Points to consider are turning the nose wheel at the correct time (before crossing the line) and applying the correct amount of thrust based on aircraft weight.

Installing the Navigraph Database to ProSim-AR (ProSim737)

No matter which avionics suite is used, the navigational database and approach charts will need to be kept up-to-date.  Navigraph (the company) have for many years been the mainstay in supplying accurate navigational data to the flight simulator community.

The navigation database and monthly updates can be downloaded from the Navigraph website, and can either be manually installed to Flight Simulator, or alternatively you can use Navigraph’s FMS Data Manager software to install the files.

This short article will benefit only those using the ProSim-AR (ProSim-737) avionics suite Version 3.  ProSim-AR Version 2 uses a different file structure and navigation path.

Database Files and Installation

Navigraph is the navigation database used by ProSim737.   The database is purchased separately to ProSim-AR and navigation updates (AIRAC cycles) are released monthly.

The correct navigational database for ProSim737 to download from the Navigraph website is: ProSim737 2.24b1 (and above).

When installed the database consists of three files:

  • cycle.json;

  • cycle_info.txt; and,

  • nd.bb3.

Cycle-info.txt is a text file that indicates which navigation database has been installed.  This is the file you need to open if you are unsure of which AIRAC cycle has been installed.  The other two files relate directly to the database.

Once the database is installed or updated, the ProSim737 main module (.exe file) must be run, and the database rebuilt.

To rebuild the database, open the ProSim main module, select Config/Database and Build Database.  The process to rebuild the database will take around 5 minutes.  When completed, the installed database AIRAC cycle number will be displayed.

Database Fails to Update

If the database does not update, there is a possibility that either the downloaded file is corrupt, or more than likely the database has been installed to the incorrect folder structure within ProSim-AR.

In this case, download the required files from Navigraph, uncompress the files to your computer desktop (or anywhere else) and copy the three database files to:

C:/Program Data/Prosim-AR/Navdata.

FMS Database Manager Mapping page.  This is where you select the folder structure to upload the AIRAC cycle to

FMS Data Manager

Navigraph have an installer (FMS Data Manager) which is a standalone program that is free to use.  The Data Manager is quite a powerful program and it’s worth the effort examining what this software can do.

When setup correctly, the installer will download, uncompress, and install the Navigraph files to the correct folder structure with ProSim.  The installer also will create a backup of the existing database (if selected).

Navigraph FMS Data Manager main front page.  This is the page where you select Update to update the navigational database with the latest AIRAC cycle

To ensure that the database is installed to the correct folder on your computer, the Data Manager must be configured correctly.  This can be done a number of ways, however, the easiest and most straightforward way is to setup the folder structure manually.

  • Open the FMS Data Manager and select Addon Mappings.

  • Select the black coloured folder adjacent to the purple coloured box named Manual.

  • Select the correct folder in your computer (C:/Program Data) and save the configuration.

To update the database, navigate back to the front page of the manager and select the check box adjacent to ProSim737 2.24b1 and select update.

ProSim-AR (ProSim737) main menu showing the Config page open with the Build Database page overlaid

Important Points:

  • Whenever you install or update the Navigraph database, rebuild the database and check the AIRAC cycle.

Final Call

Maintaining the navigation database is important if you are to get the most from Flight Simulator.  Navigraph AIRAC cycles are released monthly, and it stands to reason that the FMS Data Manager should be used to streamline the installation process.  Problems, when they do occur, usually relate to the FMS Data Manager trying to install files to the incorrect folder structure.

Reverse Thrust Procedure

The reverse thrust levers are clearly visible in the stowed position.  OEM throttle quadrant converted for flight simulator use

Pilots tend to be numbers-orientated individuals.  They like concise instructions and do not like ambiguity.  Nor do they like being presented with something that is in ‘shades of grey’ rather than ‘black and white’

When, how, and for how long to deploy the reverse thrust (reversers) falls into the 'grey area'.

In this article, I will endeavour to unravel some of the uncertainties as to when and how to use reverse thrust.  I will also briefly discuss the relationship between the use of the autobrake and reverse thrust.

I am not going to delve deeply into every environmental consideration that needs to be analysed prior to the use of reverse thrust; this information is more than readily available from the Flight Crew Operations Manual (FCOM), Flight Crew Training Manual (FCTM) and other specific airline policy documentation.

Reverse Thrust Basics

Reverse thrust (reversers) is used only for ground operations and is used after touchdown to slow the aircraft;  it is used to reduce the stopping distance, minimise brake temperatures and decrease wear and tear.

Reverse thrust comprises four détentes and an interlock position, that are engaged by moving the thrust levers from the stowed down position through to the fully up position.  

  1. No reverse thrust (thrust levers are closed / stowed position).

  2. Detent 1 (idle reverse / thrust levers are at first position).

  3. Detent 2 (thrust levers are at second position).

  4. Full maximum reverse thrust (thrust levers are at fully upward position).

Between detent 1 and full maximum reverse thrust there is scope for the thrust levers to be positioned part way; thereby, altering the amount of thrust generated.

Schematic showing various positions for the thrust reverser levers

The interlock mechanism is felt when the reverse thrust levers are advanced to detent 1. The purpose of the interlock is to restrict movement of the reverse thrust lever until the reverser sleeves have approached the deployed position.

The procedure to use reverse thrust is very straightforward, however, questions arise as to whether to use detent 2 or full maximum reverse thrust, and when to begin reducing thrust and for how long.

Procedure

Following touchdown, without delay, move the reverse thrust levers to the interlock position and hold light pressure until the interlocks release (as the sleeves move rearwards).

For most landings, detent 1 and detent 2 will usually provide adequate reverse thrust (for normal operations).  If additional reverse thrust is needed (wet, slippery or short field landing), full maximum reverse thrust can be selected by raising the thrust levers past detent 2 to full maximum reverse thrust.  

To come out of reverse, the reverse thrust levers are returned to the detent 1 position, the engine allowed to spool down, and the levers then returned to the stow position.

Practically speaking, after touchdown maintain reverse thrust as required up to maximum thrust until the airspeed approaches 60 knots. Reverse thrust is then slowly reduced to detent 1 and then to reverse idle by taxi speed. Wait until the generated reverse thrust has bleed off, then slowly close the reversers and place them in the stow position.

Bringing the reverse thrust levers to detent 1 is important because it prevents engine exhaust re-ingestion and minimises the risk of foreign object debris (FOD) ingestion.  Idle thrust also bleeds off forward thrust from the engines.

The autobrake is disarmed when a safe stop of the aircraft is assured, or when the aircraft reaches taxi speed.

Important Point:

  • If transitioning from using the autobrake to manual braking, use reverse thrust as required until reaching taxi speed and then disarm the autobrake.  

Disarming the autobrake before closing reverse thrust provides a relativity seamless transition which increases passenger comfort (there is no aircraft jolt).

Conditions Required To Engage Reverse Thrust

The reversers can be deployed when either of the following conditions occur:

  1. The radio altimeter senses less than 10 feet altitude;

  2. When the air/ground sensor is in ground mode; and,

  3. When the forward thrust levers are in the idle position.

Until these conditions occur, the movement of the reverse thrust levers is mechanically restricted and the levers cannot be moved into the aft position.

It is important to always deploy reverse thrust as soon as possible following touchdown.  Do not wait for the nose wheel to touch down, but engage reverse thrust when the main wheels are on the runway.  Timely deployment will increase stopping power; thereby, increasing safety and reducing heat build-up in the brake system.  

A study determined that there was roughly a 17 second difference in stopping time when reverse thrust was deployed immediately the landing gear was on the runway as opposed to waiting several seconds for the nose gear to also be on the runway - reverse thrust is most effectual at high airspeeds and its effect decays on a linear scale as forward airspeed decreases.

Important Points:

  • Reverse thrust should always be used with the autobrake, unless the runway is exceptionally long without a possibility of runway overrun (the reason for this will be explained shortly).

  • When closing the reversers, always pause at detent 1.  Monitor the REV thrust output on the Primary Engine Display (center panel) and stow the reversers only after reverse thrust has dissipated.

Call-outs

The pilot monitoring usually makes the following call-outs:

  • ‘60 knots’;

  • ‘Reversers normal’ -  when both REV indications are green;

  • ‘No reverser engine No: 1’ - if no REV indication or colour is amber; or,

  • ‘No reverser engine No: 2’ -  if no REV indication or colour is amber; or,

  • ‘No reversers’ -  if no REV indications or colour is amber.

NOTE:  Annunciators and displays are discussed later in the article.

During landing, the pilot monitoring (PM) should call out 60 knots to advise the pilot flying (PF) in scheduling the reduction of reverse thrust.  

When landings are in conditions that are suboptimal (heavy rain, snow, slush, etc), some operators stipulate that the PM operate and control the reverse thrust .  This enables the PF to concentrate solely on the landing roll out rather than having the extra responsibility of also controlling the reverse thrust.  

This said, although this procedure may lower pilot workload, it can cause problems when the PF is landing on a slippery runway or in marginal crosswind conditions.   At these times, the PF may wish to use the reverse thrust in conjunction with the brakes and there is little time to call out instructions to the PM.

Technical Aspects (basic operation)

Each engine on the Boeing 737 Next Generation is equipped with an hydraulically operated thrust reverser, consisting of left and right translating (moving) sleeves.  Aft movement of the reverser sleeves cause blocker doors to deflect fan discharge air forward, through fixed cascade vanes, producing reverse thrust.  

Hydraulic pressure for the operation of the thrust reversers comes from hydraulic systems A and B, respectively.  If hydraulic system A and/or B fails, alternate operation for the affected thrust reverser is available through the standby hydraulic system.  When the standby hydraulic system is used, the affected thrust reverser deploys and retracts at a slower rate and some thrust symmetry can be anticipated.

When reverse thrust is selected an electro-mechanical lock is released.  This causes the  isolation valve to open which results in the thrust reverser control valve moving to the deploy position, allowing hydraulic pressure to unlock and deploy the reverser system.

The system is designed in such a way that an interlock mechanism restricts movement of the reverse thrust lever until the reverser sleeves are in the deployed position.

Closing the thrust levers past detent 1 to the stow position initiates the command to stow the reverser.  When the lever reaches the full down position, the control valve moves to the stow position allowing hydraulic pressure to stow and lock the reverser sleeves.  After the thrust reverser is stowed, the isolation valve closes and the electro-mechanical lock engages.

Relationship with Flaps

There is an interesting relationship between the use of reverse thrust and flaps 40.

When the aircraft has flaps 40 extended, the drag is greater requiring a higher %N1 to maintain airspeed. This higher N1 takes longer to spool down when the thrust levers are brought to idle during the flare; this enables more energy to be initially transferred to reverse thrust.

Therefore, during a flaps 40 landing more energy is available to be directed to reverse thrust, as opposed to a flaps 30 landing.

Annunciators and Displays

Thrust reverse indicators are displayed in the Primary Engine Display located in the center panel slightly above the No: 1 and No: 2 %N1 indicators.  When reverse thrust is commanded, REV will be displayed initially in amber followed by green dependent upon the position of the thrust reverse levers.

  • Amber:  Thrust reverser has been deployed from the stowed position and both sleeves have travelled ~10-90% to the deployed position.

  • Green:  Thrust reverser has been deployed from the stowed position and both sleeves have travelled greater than 90% to the deployed position.

When either reverser sleeve moves from the stowed position, the amber REV indication annunciator, located on the upper display will illuminate.  As the thrust reverser reaches the deployed position, the REV indication illuminates green and the reverse thrust lever can be raised to detent 2.  

Electronic Engine Control (EEC) panel (AFT overhead). ProSim737 avionics suite virtual display

Additional reverse thrust annunciators are located on the aft overhead panel in the Electronic Engine Control (ECC) panel.  These annunciators are triggered by the retraction of the reverse thrust levers to the stow position.   

The annunciators will illuminate during a normal reverse thrust / stow operation for 10 seconds and then extinguish 10 seconds later when the isolation valve closes.  

A system malfunction has occurred if the reverser (REV) annunciator illuminates at any other time, or illuminates for more than approximately 12 seconds (in the later instance, the master caution and ENG system annunciator will also illuminate).

Possible reasons for a system malfunction are that the isolation valve, thrust reverser control valve, or one or both of the thrust reverser sleeves are not in their correct position.

Autobrake and Reverse Thrust Use (the grey area)

Both the autobrake and timely application of reverse thrust can be used to slow the aircraft, however, both come at a cost.  

Using the autobrake generates considerable heat in the braking system, translating to increased expenditure in maintenance and possible delays in turn around times (waiting for brakes to cool to operational temperature).  Conversely, reverse thrust consumes excess fuel.  Clearly there is a middle point where each will cancel out the other.

The immediate initiation of reverse thrust at main gear touchdown, and use of maximum reverse thrust, enable the autobrake system to reduce brake pressure to the minimum level – this is because the autobrake system senses deceleration and modulates brake pressure accordingly.  Therefore, the proper application of reverse thrust results in reduced braking and less heat generation for a large portion of the landing roll.

Based on this premise, it stands to reason that this is why Boeing recommend to use the autobrake in conjunction with reverse thrust.

Boeing states in the FCTM that: ‘After touchdown, with the thrust levers at idle, rapidly raise the reverse thrust levers up and aft to the interlock position, then to reverse thrust detent 2.  Conditions permitting, limit reverse thrust to detent 2’.

It appears to be Boeing’s intention to use reverse thrust as the major force to stop the aircraft, and as the use of maximum reverse thrust further minimises brake system heating, it would appear to be a preferred choice, despite the FCTM stating detent 2 is the preferred position for normal operations.

The official literature does not satisfactorily address this ‘grey area’   The result being that many 737 pilots use differing techniques when deploying and stowing the reversers.

Various Methods

If you observe how other pilots use the reversers, you will discover that there are several variations that follow the same theme.

1.    A pilot will, when the aircraft passes through 60 knots, close reverse thrust by lowering the reverse thrust levers through detent 1 to the stow position without stopping at detent 1;

2.    Try to locate detent 1 by ‘feel’ resulting in pushing the levers too far towards the stow position, causing forward thrust to unexpectedly occur momentarily;

3.    Deliberately close maximum reverse thrust at the 60 knots by placing the reverse thrust levers into the stow position.

In the above three scenarios, the reverse thrust levers have not been allowed to pause at  the detent 1 position.  Pausing at detent 1 is important as %N1 requires several seconds to reduce to idle thrust after maximum reverse thrust has been used, and it is during this ‘wind down’ period, as the reverse sleeves fully close, that %N1 will transition through 55-60%N1, which is forward thrust.  

By not allowing the reversers to pause momentarily at detent 1, to enable thrust to disparate below 55-60%N1, may cause the aircraft to momentarily accelerate.  This can be rather disconcerting, especially on a short field landing or landing in marginal conditions.

So What Do I do (normal procedure)

  1. At touchdown I engage reverse thrust – either detent 2 or maximum reverse thrust (or part thereof).

  2. Approaching 60 knots I slowly and smoothly retard the reverse thrust levers to detent 1.

  3. I always allow a few seconds at detent 1 to enable %N1 to dissipate.

  4.  Approaching taxi speed I disarm the speedbrake and close the reversers.

  • At no time do, unless in an emergency, do I close the reversers suddenly; I always close the reversers smoothly and slowly. This enables %N1 to dissipate gradually.

Final Call

The procedure to deploy reverse thrust is straightforward and very easy to accomplish, and there is little argument that reverse thrust should be used on all, but the longest runways in optimal environmental conditions.   However, there is confusion and often disagreement to when the reversers are deployed, whether maximum reverse thrust should be used, and for how long the reversers should be left in the open position before retraction and stowing.

It is unfortunate that the information written in the Flight Crew Training Manual (FCTM) and Flight Crew Operations Manual (FCOM) does not provide a more objective ‘black and white’ answer to this procedural dilemma.

Video

The below video shows the REV indicators on the Primary Engine Display (when reverse thrust is commanded) and the REVERSE annunciators on the ECC panel (AFT overhead).  Video taken directly from ProSim-AR 737 avionics suite (virtual software).  Video upload to U-Tube rather than VIMEO).