Sheepskin Seat Cover added to Weber Captain-side Seat

sheepskin seat cover added to oem weber seat

Sometime ago I acquired a pair of Weber pilot seats which came with the correct Boeing diamond-pattern, grey honeycomb seat covers.  However, one of the seat covers was slightly damaged.  The lower cover was also a tad on the small side and kept popping off the rear section of the lower cushion when you sat on it.  Not a major problem, but it was slowly becoming irritating having to repeatedly attach the cover back on the cushion.

The small size was probably caused by the previous owner washing the seat cover;  Boeing covers are renowned to shrink substantially when washed in hot water!  To rectify these minor problems, I decided to have the captain’s side upgraded to a sheepskin seat cover.

A friend of mine has access to high quality Boeing-style sheepskins and being a wizard at sewing, agreed to retrofit the cover for me.

It should be noted that sheepskin covers are not attached to the seat like you would do on an automobile.  Rather, the sheepskin is sewn directly onto the existing fabric of the original seat cover.  Colour varies somewhat depending upon the manufacturer awarded the Boeing contract, but in general they are grey to tan in colour.

I think you will agree, that the final outcome looks, and certainly feels, much better than the original damaged and too small seat cover.

B737-300 Throttle Full Automation Upgrade

oem 737-300 throttle formally used by South West Airlines. Note grey coloured throttle levers and raw aluminum handles. The boxes that contain the TOGA buttons can just be seen

The throttle quadrant installed in the simulator is from a 737-300.  When I initially  converted the throttle for flight simulator use, I choose to not have full automation included; automation being at the time fraught with issues in relation to correct and accurate operation.  

Technology rarely remains stationary and after one year of operation I’ve been reliably informed that automation can now be implemented without the problems previously experienced.  Therefore, I’ve crated the throttle quadrant and it’s now on its way to the US via DHL courier for conversion to full automation.  A process I am told that will take a few weeks.

Automation will include, at the minimum, the following:

  • 4 speed trim wheels dependent upon aircraft status (as in the real aircraft)

  • Accurate trim tab movement

  • 9 point speed brake (speed brake operation as in the real aircraft)

  • Full automation of throttle thrust handles as per MCP speed window and/or CDU

  • Hand brake release by depressing brake pedals (as in the real aircraft)

I don’t mind admitting that that my building abilities don't include complete knowledge on how to convert a 737 throttle correctly - especially in relation to automation; therefore, this task has been outsourced.

The method in which automation will be achieved is slightly different from the usual way throttles are converted, and includes some magic programming of chip sets and machining of parts to allow compatibly with ProSim737.  Taking into account Christmas and New Year, I'm hoping that the machining, installation, configuration and testing will be completed by January (2013) and the throttle will be re-installed into the simulator by February.

In a future post, I will explain the process of conversion, and how automation has been achieved with minimal use of add-on software.

Idle Time

Although the throttle quadrant and pedestal will be absent from the simulator for a short time, work will not be idle.  The conversion of the twin real B737 yokes and columns has been completed and I'm finalising installation of the second platform which incorporates linked 737 rudder pedals.  I am hoping this will be completed by mid-November.  I have discussed the new platform in a previous post.

Converting Genuine B737 Audio Control Panels (ACPs)

oem 737-400 ACP. this will be a filler until two next generation ACPs are found

I have looked at several commercially made Audio Control Panels that are available for connection to flight simulator – I did not like any of them.  They all seemed to lack a certain degree of authenticity, whether it was the LED backlighting rather than bulbs, poorly designed and moulded switches, or out of alignment cheap-looking plastic buttons.  The only ACP units that interested me where those produced by Flight Deck Solutions, however, the price for two units was greater than purchasing two genuine second-hand ACP units. 

What is an ACP

ACP stands for Audio Control Panel and the B737 has three units; one in the aft overhead and two (captain & first officer) in the center pedestal.   Each panel controls an independent crew station audio system and allows the crew member to select the desired radios, navigation aids, interphones, and PA systems for monitoring and transmission. Receiver switches select the systems to be monitored.  Any combination of systems may be selected. Receiver switches also control the volume for the headset and speaker at the related crew stations. Audio from each ACP is monitored using a headset/headphones or the related pilot’s speaker.

Simply, the ACP is a glorified sound mixer.

Finding second-hand ACP units from a B737-800NG is next to impossible, so the next best thing are units removed classic series 737s.  The units I am using were manufactured by Gables Engineering in 2004 and have been removed from a B737-500.  It is unlikely that ACP units from an earlier series aircraft would be used in the NG, as the NG ACP unit design is different.  But, for a home-made simulator the use of older ACP units fulfils the same roll and is a very good stop-gap until a OEM NG panel can be procured.

When you begin to search for ACP units, you will discover there are a large number of different designs available.  The design can be correlated to the era of the unit.  Earlier units used sliders and turn dials while later models utilised push buttons.   Many of the slider-style units were used in 727s. 

Conversion of ACP Unit to Flight Simulator - Several Methods

It is difficult to document exactly how a conversion is done.  There are many variables to consider and genuine parts and flight simulator set-ups can be different.  By far the most challenging task is determining which wire from the 55 pin plug controls which ACP function.

oem 737-400 ACP unit with outer shell removed.  Most of this will be removed with the exception of the switches.  The wiring can be removed and replaced or unraveled and used directly

Removing Unwanted Wiring

You can either start afresh and after removing the outer aluminium casing, strip most of the wiring from the unit, along with discarding unwanted solenoids, relays and the large circular 55 pin plug at the rear of the unit; or keep the wiring and 55 pin plug and attempt to determine which wire goes where and and connects with what function. 

When finished removing much of the unwanted interior you will be left an almost empty container and some hardware and electrical circuits (buttons and switches).  Most of the switches are triple push switches and you must be careful to not damage the internal mechanism of these switches.

Which Wire Goes Where and Connections

There are two ways to convert the unit:  The first is to use existing wiring and determine which wire goes to what button/switch to reflect whatever functionality; this can be a time-consuming, challenging and frustrating task.  Once the wire to a function has been found, you must identify the wire with a flat tab or other physical marking device.  Each wire is then directed to an interface card.

The second method is a little easier.  Remove all the wires are rewire the unit.  This way there is no double-guessing that you have the correct wire.

If you have opted for the slightly easier second method of removing all the wiring from the unit and starting afresh, you can now recycle the same wire and solder the wires to the appropriate switches.  Recycling in motion :)

Determining Functionality

One method to determine functionality is to use a digital multi meter.  Set the meter to either continuity or resistance, select a wire connected to a switch and place the probe at the open end of the wire.  Identifying the correct wire/switch will cause the meter to either emit an audible beep or display a resistance on the display.  This is the wire that connects this function.

Once the wires have been identified and connected to the correct hardware switches within the ACP unit, they are then connected to an interface card.  I have used a Leo Bodnar BU0836X card which has available a large number of inputs and outputs. 

The Leo Bodnar card provides the interface between the ACP units and flight simulator.

To keep the wiring tidy, bundle the wires into a wiring lumen terminating in a solid plug / connector.  In my case I've used a standard style 18 pin computer connector. 

It is important to use a plug, rather direct the wires directly to the interface card, as you may wish to remove the ACP units at some stage.  A plug allows easy removal and connection.

Leo Bodnar card and two wire rails connected to acyclic board.  The vertically mounted wire rail provides a strong support from which to solder the wires.  The two computer plugs connect to the rear of each ACP unit.  The other small blue coloured card is an FDS power connection card used to daisy chain 5 Volt  power to the FDS modules I am using

Wiring Harness, Rail and Backlighting

A wiring harness was constructed to facilitate easier connection of the wires from the ACP units to the interface card. The harness and Leo Bodnar card is attached to a thick piece of acrylic plastic which in turn was mounted to a piece of wood that fits snugly within the center pedestal.

Wire Rail

Each ACP unit has a dedicated 'wire rail' attached to an acrylic plastic base.  The purpose of this rail is to provide an interface between the ACP units and the Leo Bodnar card.  Whilst this interface is not absolutely necessary, it does allow for identification of the wires (numbering system seen in photograph above).  Furthermore, it also provides a stable and solid base to secure wires between the interface card and each of the ACP units.

It should be noted that the rail also acts as a Y-junction to filter the outputs from two ACP units into one, which connects to the interface card and flight simulator.

The wires from the rail are then soldered to a standard style computer plug which connects to its male  equivalent mounted to the rear of each ACP unit. In essence we have three parts to the system:

  1. A re-wired ACP unit with wires terminating in a plug on the rear of the unit. 

  2. A wire rail which sits between the two ACP units and the interface card (Y-junction).

  3. An interface card that  connect with the wire rail and then to flight simulator via a USB cable.

Soft amber glow of ACP unit back lighting at night.  The light plates of genuine units always use globes rather than LED lights.  Power is 5 Volts DC and the amperage draw is around 1 AMP

Backlighting

The wires which carry power to illuminate the back lighting are wired directly from the light plates located in each ACP unit to a small electrical terminal block mounted to the rear of the unit.  The power wire is then directed to the panel light switch, located on the center pedestal. 

The panel light switch, located on the center pedestal,  controls back-lighting to the throttle quadrant, center pedestal and to the trip indicators on the yokes.  The reason for breaking this power wire with a two-wire terminal block is to allow removal of the ACP unit if necessary.  If you wanted to, you could use a pencil style audio push-in style plug.

A single USB cable from the Leo Bodnar card connects the ACP units to the main FS computer.

Synchronised Units - Limiting FSX Factor

In a real aircraft each ACP unit is separate to each other and can be configured independently, however, flight simulator (FSX) falls short in this area and uses only one ACP unit to mimic button presses across all units. As such, it was pointless to wire each unit separately and independent of each other.  Therefore, both ACP units mimic each other in functionality and output. 

For example, the ADF1 button can be pressed on the captain-side ACP unit to turn ADF1 on.  If you then press the same button on the flight officer side unit, ADF1 will be turned off.  This is another reason why a wire rail, mentioned above, was used; to act as a Y-junction.

NOTE (January 2015): ProSim737 now allows configuration of all buttons on the Captain and First Officer ACP units.  ProSim737 now allows independent selection of an ACP unit (up to three) removing the earlier FSX-imposed limiting factor.  Both units have been re-wired to take this into account.

Converted ACP unit showing replacement wiring and 18 pin computer style plug.  The circular hole in the rear below the plug is where the 55 pin plug was removed

Control - Captain or First Officer

Some enthusiasts wire units so that the Captain side is always the main controlling unit.  In my set-up, the wires from each ACP unit are fixed to the 'wire rail' and then to the Leo Bodnar card.  This allows you to be able to choice either side as the controlling unit.  The downfall being that whatever side is not in control must have the correct buttons pre-selected for correct operation.

Ingenious Design

One very interesting aspect of the ACP units is how Gables Manufacturing has designed the buttons to illuminate light when activated.  I initially thought that each button would have a separate bulb; however, this is incorrect.  The light which illuminates a button when engaged, comes directly from a number of strategically positioned bulbs.  An ingenious design incorporates a small reflector dish similar to an old style camera flash unit, to stop light reaching the button when it is in the unengaged position.  Engaging the button moves the dish into alignment which reflects back light into the button’s clear acrylic interior.  

Although an ingenious design, you must be very careful if handling a button to ensure that the reflector, which is positioned between the base of the button and light plate, does not 'bounce' away to be lost.

Configuring Functionality

Configuring ACP functionality, once the wiring is correctly connected, is straightforward and can either be done directly through the control panel in FSX, through FSUIPC or directly from within ProSim737.

The pencil-style and square-type buttons of each ACP unit allow quite a bit of functionality to be programmed when using FSUIPC.  Not every ACP feature, used in a real aircraft is replicated in flight simulator; therefore, those buttons not used for essential audio functions can be used for other customised functions.  

The most important functions (in my opinion) to have working are the indents for: VHF, NAV 1/2, ADF 1/2, MRKS (markers) and DME.  COM 1/2 transmit buttons can also be configured easily in FSUPIC to use  when flying on VATSIM or IVAO.

I have not configured the audio (volume) on the pencil-style buttons; however, it may be possible to configure these at some later stage using a separate sound card.  I believe the potentiometers  range from 11.90 - 12.00 K Ohms.

Aesthetics

I think you will agree that the OEM ACP units, even if not NG style, look much better than replicated modules – even if they are not the latest NG style:  the genuine buttons and switches, the soft amber glow of real Boeing back-lighting, and the substantial build of the units generate a high level of immersion.

NG Style ACP Units

The units are not NG style, however, as New Generation parts come on-line, I will replace these units with the more modern style.  it iss just a matter of waiting for 600 and 700 series units to become available.

I've compiled a short video using Ken Burns effect.

 

737-500 ACP conversion (Ken Burns effect)

 

POST SCRIPT - An Easier Method: Schematics to ACP Units and 55 Pin Outs

At the time of my conversion, I did not have available a schematic showing the pin outs for the ACP unit.  This meant any conversion had to be done from scratch (as documented above). 

I now am in  possession of the ACP schematic diagram, which includes a pin out diagram indicating what function each pin of the available 55 pins on the rear plug connects to. 

diagram !: standard 55 pin plug found on Gables ACP units

If another conversion is required, the wiring will be a lot simpler as the wires will not need to be striped from the unit and re-done.  All that will be needed is to attach wires from the Leo Bodnar card directly to the 55 pin electrical plug already mounted on the rear of each ACP unit (I have been reliably informed, that thin 1mm copper pipes obtainable from modelling supplies fit perfectly), and connect the light plates to a 5 Volt DC power source. 

Minor Complications

At first, using the 55 pin plug appears to be an easy method of conversion, however, there is a minor set-back.  The COM radio cannot be connected; it is probable that on the real aircraft the MIC selectors are routed via onboard amplifiers rather than via the plug.  Therefore, if these functions are required, they will need to be converted by rewiring and connecting to a accessory plug of some type (as has been done documented in the first section of this post).

Do Not Reinvent The Wheel - Canon Plugs

It is important to always try and convert any OEM part using the Canon plugs and pin outs before rewiring any part.  Gables have already done an excellent job  wiring the panel internally, so why not utilise this wiring by using the existing Canon plug system.

This ACP panel is the only panel that has been converted this way in the simulator.  It was the first panel that was converted and at the time I did not understand the Canon plug concept in its entirety.  All other panels have been converted using the existing plug system avoiding rewiring the unit.

Update

on 2020-07-05 01:50 by FLAPS 2 APPROACH

One minor problem observed using the standard Leo Bodnar interface card, is that the connection of the wires into the card kept working their way loose, resulting in a break in the connection.  This problem identified itself by giving incorrect button designations on the ACP units.  No matter how hard I pushed the wires into the holders on the card, the wires eventually worked their way out a tad.

To solve this issue, I replaced the BUO836X card with the Leo Bodnar BBI-32 Button Box card.  The BB1-32 card allows the wires to be soldered in place.

Update

on 2015-07-30 06:20 by FLAPS 2 APPROACH

Following on with converting as many units to be 'plug and play', the ACP units were once again revamped to allow the Leo Bodnar card to be installed inside the Captain-side unit. 

Captain-side master ACP showing reworked connectors.  One straight-through cable connects between the master and the F/O ACP (slave) while the other cable connects with its mate inside the pedestal bay.  The USB cable connects with a USB hub located in the pedestal.  If I was converting the ACP units again, I would definitely use Canon plugs

The Captain-side ACP is the 'command' unit and the F/O ACP units acts as a 'slave'.  A straight-through cable connects both units via D-sub plugs (the computer-style terminal plugs were removed).   A single USB cable connects the Captain-side ACP to the computer. 

Further, the limiting aspect of having to have the F/O side activated to allow functionality to occur on the Captain side has been removed.  Historically, FSX has only allowed the ACP units to operate from the Captain side.  ProSim737 enables operation of three ACP units, so this limiting factor is now removed. Each button on both ACP units has been wired to allow separate control.

The benefit of installing the joystick card inside the unit is it removes the large amount of wiring that  previously used valuable real estate space within the center pedestal.  

Update

on 2022-05-09 12:26 by FLAPS 2 APPROACH

This conversion was completed sometime ago (2014-15).  Today (2020) there are more efficient and easier ways to convert the ACP units that do not require the unit to be completed gutted.  Certainly, the outcome is identical, but the method different.

  • If converting another ACP unit, I would not use the method documented above.

Using Genuine B737 Aviation Parts

A colleague grinding the tails from genuine DZUS fasteners. These will then be attached to reproduction modules to enhance their appearance

There is something fundamentally different when using a genuine piece of aircraft equipment instead of a replicated item – It’s difficult to define, but the idea of using a piece of hardware that flew thousands of flight hours, in good and bad weather, has a certain appeal.

You will notice when you peruse the below list that many parts are not Next Generation, but are from classic 737 airframes, Finding Next Generation components is time consuming and can have long lead times. In the interim, I am using classic parts as fillers. Fortunately, some components used in the classics, especially the 737-500 are also used in the Next Generation.

The following OEM parts are currently used and converted:

  • 737-500 yokes and columns (2)

  • 737 Captain-side stick shaker

  • 737-300 throttle quadrant

  • 737-300 telephone and microphone

  • Jetliner style aviation headset (was formally used in an United B737)

  • 737-300 three-bay center pedestal

  • 737-400 fire suppression panel

  • 737 yoke trip indicators (2)

  • 737 rudder pedals (2)

  • 737-500 audio control panels (2)

  • 737 Weber captain and first officer seats

  • MD-80 clock (flight officer side of MIP)

  • 737 overhead map light

  • 737 korry switches

  • 737-500 tiller handle

  • 737-300 Forward & Aft Overhead Panel w/ Coles engine switches & genuine light switches

  • DZUS fasteners

  • 737-800 flap guage

  • 737-800 Yaw Dampener gauge

  • 737-800 brake pressure gauge

I would like very much like to replace the ADF and NAV modules with OEM panels; however, need to research the feasibility in doing this.  In the meantime, I’m using reproduction navigation radios manufactured by Flight Deck Solutions.

Historical Significance

The historical significance of using genuine parts cannot be ignored.    It’s relatively easy to research an aircraft frame number or registration number and in the process learn where the aircraft was used and in what conditions.  

For example, the throttle unit I am using was removed from a South West B737-300 that plied the continental USA for many years, whilst the yokes and columns were previously used in a B737-500 operated by Croatian Airlines.  The clock I have for the flight officer side of the MIP came from a FedEx MD80 and one of the ACP units was used by Aloha Airlines in Hawaii.

Recycling

Using OEM used parts helps the environment!  

For a start, you are not purchasing new reproduction parts made from virgin resources.  Secondly, the used parts you bought probably would have been destined for expensive recycling, or alternatively disposed of to landfill.  

Recycling can be fun!!  

It’s a good feeling to convert something destined for disposal and bring it back to life.

Toughness

One of the major benefits of using OEM aircraft parts is their longevity and ruggedness.  Whilst none of us want to damage our simulators through over zealous use; it can and does occur from time to time.  Replica parts are – well a little delicate.  To ensure long life you must treat them with care.  

It’s the opposite with genuine aircraft parts; damaging a genuine part with normal use is almost impossible.  

For example, a speed brake lever is relatively easy to bend or break on any number of replica throttle quadrants on the market; damaging a genuine speed brake handle is very difficult as they are constructed from high grade materials to withstand genuine stresses (pilot-driven or otherwise).

Simulation pilots are often as rough on their gear as genuine pilots are; I’ve seen simmers jab ACP buttons with enough force to break a piece of plastic.  Genuine buttons are made to withstand this heavy-handed treatment, replica parts – break!

Aesthetics – Look Your Best

It’s a fact; aN oem aircraft part looks 100% more realistic than a simulated part – that’s obvious.  If your center pedestal has an assortment of genuine modules mixed in with replica modules, the pedestal will appear much more authentic than one comprised solely of simulated units.

You will be surprised that small things can make a huge aesthetic difference.  Take for example, DZUS fasteners.  I bought a box of fasteners sometime back and use them wherever I can to replace the reproduction fasteners or screws that many manufacturer’s use.  If the fastener does not fit the appropriate hole in the reproduction module, I either enlarge the hole with a drill bit, or if this isn’t feasible, I cut the tail from the fastener leaving only the DZUS head.  I then use a piece of sticky blue tack or crazy glue to secure the DZUS head to the appropriate part.  

OEM B737-300 two-bay center pedestal showing mix of reproduction and oem components

The fasteners I've used were purchased second-hand; therefore, they show wear and tear.  I don’t mind this used and abused look.  Yes it sounds rough and ready, but the end result looks very pleasing to the eye and more faithful to what you would see in an operational flight deck.

The confines of the flight deck are not as clean as one might expect, and instruments are scratched and dented; pilots rarely concern themselves with aesthetics and technicians complete their maintenance quickly, as an aircraft not flying equates to lost revenue for the airline.

The use of genuine parts adds to the immersion factor, and as a Dutch simmer recently commented: “It makes the simulator more alive”

Availability of Parts

oem aircraft parts can be difficult to find and it’s a hit and miss affair.  As newer aircraft are brought online, airlines scrap their older fleet and parts become readily available.   

Finding late model Next Generation parts, at a reasonable price is almost impossible; these parts are still serviceable.  Parts in older aircraft may also be serviceable; however, they must meet safety regulations and be inspected and approved by a certified agency.  This process is expensive and many airlines find it cost prohibitive; therefore, parts are sold as scrap.

E-Bay can be a good place to find parts.  Search for aviation parts - Boeing, 737 or Gables.  Aviation scrap yards are also invaluable, as are the classified sections in various flight simulation forums on the Internet such as My Cockpit and Cockpit Builders.

Conversion - Use in Flight Simulator

This can be minefield to the uninitiated.

OEM parts often operate on a variety of voltages, and it’s not uncommon to need 5, 12, 18 and 24 Volt power supplies to enable an OEM part to work correctly.  Further, the wiring inside the neat-looking box can be a rat’s nest of thin wires weaving their way to and from a variety of unidentified pieces, before terminating in an electrical connection rarely found outside the aviation industry (Canon plug).

I am not an expert in conversions (although I am learning quickly.....).  I’m lucky in that I have access to a few people who are very knowledgeable in this area and are happy to share their knowledge with me.  

Interfacing

There are a number of ways to interface an OEM part with flight simulator.  The easiest is to use is a Leo Bodnar BU0836 joystick card, or similar, using standard flight simulator commands and/or FSUIPC.  The use of these cards makes assigning functionality in flight simulator very easy and straightforward.

One BU0836 card provides 12 inputs which correlates to 12 individual switches or buttons.  The 0836 card also has the capability to have a matrix constructed which increases the number of available outputs.  Another joystick card that is very good and easy to configure is the PoKeys card.

The inside of a 737-500 ACP module showing the rat’s nest of wiring that can be found within an OEM module

For functionality that requires movement, a servo motor will need to be used and configured in FS2Phidgets.  Phidgets allow you to program almost any moving part, such as the needle of the rudder trim module or the trim wheels of a throttle unit.    Digital servos are better than analogue servos as the former do not make an audible squeaking noise when connected to power.

By far, the most difficult part of any conversion is discovering what wire connects to what functionality.  Finding the wire can be challenging in itself as most avionics modules are a nest of wires, diodes and electronic circuitry.

You Have A Choice

You don’t have to use reproduction simulator parts throughout your flight deck – there is a wide selection of used aviation parts available, and with a little searching, you probably can find what you want.  

OEM parts frequently can be found at far less cost than their reproduction counterparts, and in every case will always look more visually appealing.  If you’re not up to the task of conversion, there are individuals that can convert modules for you.  You will then need to configure the functionality in FSUIPC or directly in the avionics suite used.  At the very minimum, using DZUS fasteners will bring your simulator to the next level of realism.  But be warned, using OEM parts evokes a desire to replace anything replica with something real.

In my next post we will look at converting two genuine B737 Audio Control Panels (ACPs) to flight simulator use.

Ground Effect - Historical Perspective & Technical Explanation

usaaf b17 flying fortress (USAAF, B17-F-45-VE (cropped), marked as public domain, more details on Wikimedia Commons)

During the Second World War, a crippled Boeing B17 was struggling to maintain altitude.  The aircraft and eleven crew members were over occupied Europe, returning to England, following a successful bombing mission.

Searchlights, Flak & Enemy Fighters

After negotiating the enemy searchlights that probed the darkness over their target, and then being struck by shell fragments from anti-aircraft flak, they were pounced upon by German fighters on their homeward leg.  The ensuring fight was dramatic and left the damaged bomber with only two engines running and third engine having difficulty.  As the bomber approached France, the enemy fighters, starved of fuel, aborted their repetitive attacks, but the damage had been done.  Loosing airspeed and altitude the aircraft could not maintain contact with the Bomb Group; soon they were alone.

The captain, in an attempt to maintain altitude, requested that everything heavy be jettisoned from the aircraft.  This included machine guns, ammunition and damaged radio equipment; soon the B17 was a flying skeleton if its former self.

The Captain was concerned that a fire may develop in engine number three as it was spluttering due to a fuel problem.  The Captain did not need to concern himself much longer, for the engine began to cough uncontrollably before vibrating and ceasing to function.   The aircraft was now only flying on one engine – something not recommended, as it placed great strain on the engine and aircraft superstructure.  

The aircraft continued to loose altitude despite the jettisoning of unwanted equipment.  The Captain decided it was better to ditch into the English Channel rather than land in occupied France.  His thinking was that Air Sea Rescue maybe able to pick them up, if their repeated morse code (SOS) had been received by England.  The power of one engine was nowhere enough to maintain such a large and heavy aircraft and the crew prepared to ditch into the freezing cold water of the channel.

We’re Going In – Good Luck Boys!

“Get ready guys, we’re 300 feet above the water” yelled the Captain into his intercom system.  “As soon as we hit bust them bubbles and get out.  Try to get a raft afloat”.  “Link up in the water  – Good Luck!”

Everyone expected the worse.  Surviving a ditching was one thing, but surviving in the cold water of the English Channel in winter was another!  The rear gunner, since moving forward sat close to escape hatch and gingerly rubbed his rabbit’s foot; he had carried this on every mission.  The side gunner fumbled repeatedly with his “lucky” rubber band, the bombardier sat in private thoughts, a photograph of his loved one held tightly in his hand, and the navigator frantically punched his morse set trying to get the last message out before fate took command of the situation.

The aircraft, although trimmed correctly, slowly began to dip towards the sea.  But at 60 odd feet above the waves, the aircraft began to float  – it felt as if the aircraft was gliding on a thermal.  For some reason the aircraft didn't wish to descend.  The remaining engine screamed its protest at being run at full throttle, however the horizontal glide continued. 

The Captain was amazed and thankful for whatever was keeping this large aircraft from crashing into the sea.  It was as if the B17 was cruising on a magic carpet of air – why didn’t it crash.  

A tail-wind assisted in pushing the B17 toward England and safety; seeing the English coast in sight, the navigator quickly calculated a route to the nearest airfield closest to the coast.  Twenty minutes later the bomber lumbered over the runway.  The only way to land was to reduce power to the remaining engine and push the control wheel forward, thereby lowering the pitch angle.  They were home and safe!

Divine Interaction, Luck, or Skill ?

The crew thought it was divine interaction that the bomber had not crashed – or perhaps luck!

Aviation engineers were baffled to what had occurred.  The aircraft had glided many miles above the surface of the English Channel and had not crashed.  Boeing, in an attempt to unravel what had occurred, repeated the event in the confines of a wind tunnel, to realize that what had maintained the large aircraft airborne was not divine interaction, but the interaction of what has since been termed Ground Effect.

The above account, although embellished in detail, did occur.  The mishaps of this bomber during the Second World War demonstrated a previously unknown phenomenon - Ground Effect.

Ground Effect – Technical Explanation

Ground effect refers to the increased lift and decreased drag that an aircraft wing generates when an aircraft is about one wing-span's length or less over the ground (or surface).  The effect of ground effect is likened to floating above the ground - especially when landing.

When an aircraft is flying at an altitude that is approximately at, or below the same length of the aircraft's wingspan, there is, depending on airfoil and aircraft design, a noticeable ground effect. This is caused primarily by the ground interrupting the wingtip vortices, and the down wash behind the wing. 

diagram 1: ground effect in the air

When a wing is flown very close to the ground, wingtip vortices are unable to form effectively due to the obstruction of the ground. The result is lower induced drag, which increases the speed and lift of the aircraft.

The two diagrams depict aircraft in ground effect whilst on the ground and in the air.

diagram 2: ground effect on the ground

A wing generates lift, in part, due to the difference in air pressure gradients between the upper and lower wing surfaces. During normal flight, the upper wing surface experiences reduced static air pressure and the lower surface comparatively higher static air pressure. These air pressure differences also accelerate the mass of air downwards.  Flying close to a surface increases air pressure on the lower wing surface, known as the ram or cushion effect, and thereby improves the aircraft lift-to-drag ratio.  As the wing gets lower to the surface (the ground), the ground effect becomes more pronounced.

While in the ground effect, the wing will require a lower angle of attack to produce the same amount of lift. If the angle of attack and velocity remain constant, an increase in the lift coefficient will result, which accounts for the floating effect. Ground effect will also alter thrust versus velocity, in that reducing induced drag will require less thrust to maintain the same velocity.

The best way to describe ground effect and which many people, both pilots and passengers, have encountered is the floating effect during the landing flare.

Low winged aircraft are more affected by ground effect than high wing aircraft. Due to the change in up-wash, down-wash, and wingtip vortices there may be errors in the airspeed system while in ground effect due to changes in the local pressure at the static source.

Another important issue regarding ground effect is that the makeup of the surface directly affects the intensity; this is to say that a concrete or other hard surface will produce more interference than a grass or water surface.

Problems Associated With Ground Effect

Take Off

Ground effect should be taken into account when a take-off from a short runway is planned, the aircraft is loaded to maximum weight, or the ambient temperature is high (hot).

Although ground effect may allow the airplane to become airborne at a speed that is below the recommended take-off speed, climb performance will be less than optimal.  Ground effect may allow an overloaded aircraft to fly at shorter take off distances and at lower engine thrust than normal.  However, the aircraft will not have the ability to climb out of ground effect and eventually will cease to fly, or hit something after the runway length is exceeded.

Approach and Landing

As the airplane descends on approach and enters ground effect, the pilot experiences a floating sensation which is a result from the increased lift and decreased induced drag value. Less drag also means a lack of deceleration and could become a problem on short runways were roll-out distance is limited.

Therefore, it's important that power is throttled back as soon as the airplane is flared over the threshold and the weight of the airplane is transferred from the wings to the wheels as soon as possible.

How to Counter Ground Effect

To minimise ground effect on landing, the following must be addressed:

  • Pitch angle should be reduced to maintain a shallow decent (reduces ability of the wing to produce more lift).

  • Thrust should be decreased.

  • The power should be throttled back as you cross the threshold at ~RA 50 feet (note that in simulation ~10-15 feet is more effective).

  • Land the aircraft onto the runway with purpose and determination.  Do not try and grease the aircraft to the runway (often called a carpet landing).  The weight of the aircraft must be transferred to the wheels as soon as possible to aid in tyre adhesion to the runway (also important when landing in wet conditions).

Does Ground Effect Occur in Flight Simulator?

If the aircraft is not set-up correctly, ground effect will definitely be experienced in a flight simulator. 

If you have ever wondered why, after reducing speed on an otherwise perfect approach, your aircraft appears to be floating down the runway, then you have already experienced ground effect.

List of B737 Carriers Worldwide - Interesting....

first boeing 727. lufthansa 1968 (Comet Photo AG (Zürich), ETH-BIB Com F66-08148 Lufthansa Boeing 727-3C D-ABIC Zuerich-Kloten 060766, CC BY-SA 4.0)

A Boeing 737 takes off or lands somewhere in the world on average every 5 seconds!

To date, the Boeing series of airliners is the most successful airliner the world has seen.  Boeing's success revolves around, amongst other things, the ability to be able to upgrade their aircraft from a basic overall design that has changed little since the first 727 rolled out of the hanger in the 1968, earmarked for the German airline Lufthansa.

So which nations place their trust in Boeing?  This link provides a list of worldwide carriers by nation.

Creating Waypoints on the Fly with the CDU

Often you need to inject into the flight plan a Place Bearing Waypoint or an Along Track Waypoint.  There are several ways to do this with each method being similar, but used in differing circumstances.  Depending upon the FMC software in use, either the LEGS or the FIX page is used.

A Place Bearing Waypoint (PBW) is a waypoint along a defined bearing (radial) that is created at a specified distance from a known waypoint or navigation aid (navaid).  A PBW is used to create  a waypoint that is not in the active route.

An Along Track Waypoint (ATW) is a waypoint inserted into a route that falls either before or after a known waypoint or navaid.

Although the PBW and ATW are similar, they are used in differing circumstances.

  • In the following examples I will use the waypoint TETRA as an example.  TETRA is a waypoint near Narita, Japan (RJAA).

Creating a Place Bearing Waypoint

  • Type into the scratchpad the waypoint name, bearing and distance.

    For example, type into the scratchpad a TETRA340/10.  TETRA is the waypoint that we want to create the new waypoint from.  This is called an anchor waypoint.  340 is the bearing in degrees from the anchor waypoint that the new waypoint will be generated.  10 is the distance in nautical miles from the anchor waypoint that the waypoint will be generated at.

  • Up-select TETRA340/10 to the LEGS page. 

  • Press EXECUTE.

To insert the waypoint before the anchor waypoint use the negative key (TETRA340/-10).  Do not use the negative symbol if you want to insert the waypoint after the anchor waypoint (TETRA340/10).  Take note that the slash (/) is after the bearing and the waypoint name and vector are joined with no spaces.

Creating an Along Track Waypoint

  1. Type into the scratchpad the waypoint or navaid that will be used as an anchor waypoint.

  2. Up-select this into the correct line of the route in the LEGS page.

  3. Press EXECUTE.

Important Points:

  • If the waypoint is already part of the route, it is not necessary to type the identifier in to the scratchpad.  Rather, press the appropriate Line Select Key adjacent to the identifier (in the LEGS page) to down select to the scratchpad.  Then add the /-10 or /20 after the identifier and up-select.  Using this method eliminates the possibility of typing the incorrect identifier into the scratchpad.

  • The FMC software will generate subsequent waypoints with a generic name and numerical sequence identifier.  For example, TETRA, TETRA01, TETRA02, TETRA03.

Creating a Circle around a Waypoint using the FIX Functionality

The purpose of creating a circle (ring) around a point in space is to increase spatial awareness when looking at the Navigation Display (ND).  A circle at a set distance may be used to define the Missed Approach Altitude (MAA), the distance from the runway threshold that the landing gear should be lowered, or to designate an important waypoint.

I nearly always use two or three circles depending upon the approach being executed.  One circle will be at 12 miles while the second circle will be at 7 miles.  The use of circles can be very helpful when flying a circle-to-land approach; one circle will define the MAA and the other circle will define the  'protected area' surrounding an airport.

To create a circle (ring) around a known point

  1. Press FIX on the CDU to open the FIX page.

  2. Type into the scratchpad, the name of the waypoint or navigation aid (VOR, NDB, etc).  For example TETRA.

  3. Up-select this to the FIX page (LSK1L).

This will display a small circle around the identifier in the Navigation Display in green-dashed lines.

If you want the circle to be at a specific distance from the point in question.

  1. Type into the scratchpad the distance you require the circle to be drawn around the waypoint.  For example /5.

  2. Up-select this to the FIX page (LSL2L).

To add additional circles around the selected point, repeat the process using different distances and up-select to the next line in the FIX page.

Important Point:

  • A quick way to insert a waypoint from a route into the FIX page is to press the waypoint name in the LEGS page.  This will down select the waypoint to the scratchpad saving you the time typing the name and removing the possibility of typing the incorrect letters.  Up-select to the FIX page.

Creating a Single Along Track Waypoint (at the edge of the circle)

One or more waypoints can be created anywhere along the circumference of the circle (discussed earlier) by inserting a bearing and distance into the FMC page.  

To create a waypoint at the edge of the circle

Create a circle around a point as discussed earlier (TETRA).

  1. Type in the scratchpad the bearing and distance that you wish the new waypoint to be created (for example 145/5).

  2. Up-select this information to the FIX page (LSK2L). This will place a green-coloured line on the 145 degree radial from the waypoint (TETRA) that intersects a circle at 5 miles on the ND.

  3. Next, select the 145/5 entry from the FIX page (press LSK2L).  This will copy the information to the scratchpad.  Note the custom-generated name – TETRA145/5.

  4. Open the LEGS page and up-select the copied information to the route.  Note that TETRA145/5 will now have an amended name – TET01.

  5. Copy TET01 to the scratchpad.

  6. Open a new FIX page (there are 6 FIX pages that can be used).  Up-select TET01 to the FIX page (LKL1L).  This will create a small circle around TET01 on the ND.

  7. To remove the waypoint (TET01) from the route (if desired), open the LEGS page and delete the entry.   If desired, the waypoint can easily be added again to the route from the FIX page.

The above appears very convoluted, however once practiced a few times it becomes straightforward.  There is a less convoluted way to do this, however, the method is not supported by ProSim737.

Inserting an Additional Along Track Waypoint around the Arc of the Circle (DME Arc)

A DME arc is a series of Along Track Waypoints that have been created along an arc at a set distance from the runway (waypoint or navigation fix).  This is often used when flying a NDB Approach.

Usually, the arc begins on the same bearing as the navigation track of the aircraft, and ends a set point, usually at the turn from base to final.  Subsequent bearings after the initial bearing are at a 30 degree spacing.

To create a DME Arc

First, ensure you have a circle created around the waypoint (TETRA) at the distance required (FIX page).

  1. Select the anchor waypoint (TETRA) for the arc from the LEGS page and down select it to the scratchpad.

  2. Type into scratchpad after TETRA (as separate entries) the bearing and distance.  For example: TETRA200/5, TETRA230/5, TETRA260/5, TETRA290/5 TETRA320/5 and so forth.  Note the bearings differ by 30 degrees.  This creates the arc.

  3. Up-select each of the above entries to the route in the LEGS page (after the anchor waypoint TETRA).

This will create an arc 5 miles from TETRA.

If you want the first waypoint to be along your navigation track, use the bearing for this initial waypoint as indicated in the LEGS page of the CDU.

The FIX page can also be used to create an arc using the same technique.  Using the FIX page will enable the arc to be seen on the ND, but not form part of the route.

Important Point:

  • It is important to note that user and along track waypoints are given a generic name and numerical sequence identifier by the FMC software (TETRA01, TETRA02. TETRA03, etc).

Understanding the CDU

What I have described above is but a very brief and basic overview of some functions that are easily performed by the CDU.

CDU operation can appear to be a complicated and convoluted procedure to the uninitiated.  However, with a little trail and error you will soon discover a multitude of uses.  It is important to remember, that there are often several ways to achieve the same outcome, and available procedures depend on which FMC software is in use.

I am not a professional writer, and documenting CDU procedures that is easily understood is challenging.  If this information interests you, I strongly recommend you purchase the FMC Guide written by Bill Bulfer.  Failing this, navigate to the video section of this website to view FMC tutorials.

 

Navigation display showing map view. Left to right.

image 1:  5 mile ring surrounding TETRA.

image 2: 2 and 5 mile ring surrounding TETRA.

image 3: 5 mile ring surrounding TETRA showing PBW on circumference TET01.

image 4: DME arc along circumference of 5 mile ring surrounding TETRA.

 

Acronyms

Anchor Waypoint – The waypoint from which additional waypoints are created from.

Bearing – Vector or radial.

CDU – Control Display Unit.

FMC – Flight Management Computer.

ND – Navigation Display.

Target Waypoint – The waypoint that has been generated as a sibling of the Anchor waypoint.

Waypoint – Navigation fix, usually an airport, VOR, NDB or similar.

  •  Updated 05 June 2022.

737-800 Primary Flight Display (PFD) Diagram

pfd diagram (smart cockpit)

The simple to understand picture is an excellent visual reminder to the most important areas of the Primary Flight Display (PFD) in the 737-800.

When I was new to jets, I had this image printed in colour above the computer screen as a quick reference guide. It doesn't take long before it’s second nature and you no longer need to reference the diagram.

I will let you fill in the appropriate text beside the numbers.

JetStream 738 by ProSim737 - Review

After flight testing several aircraft models, I decided to use the B738 (FS9 version) produced by Precision Manuals Development Group (PMDG).  This flight model, once the PMDG flight logic is removed, functioned exceptionally well and is very stable.   

One of the potential problems when using a flight model produced by another company is compatibility and functionality with your chosen avionics software suite.  Minor problems are often solved by tweaking the aircraft.cfg file; however, tweaks are just that, and often issues will occur which cannot be identified and rectified.  In my experience, tweaking the .cfg file may solve your initial problem, but may cause additional errors elsewhere.

Different Aircraft Models – Different Solutions

To ensure various aircraft models operate with their software, Sim Avionics provide users with specific aircraft.cfg files that correspond to the particular flight model they are using.  These files are optimally tweaked to the Sim Avionics software.

ProSim737 has handled the problem of aircraft model variances slightly differently.  Rather than provide a tweaked aircraft.cfg file to allow you to use whatever flight model you wished, they took a holistic approach and produced a complete aircraft dedicated ONLY to their avionics software suite.

Creating an aircraft model that is designed to only operate with their software has many advantages.  First and foremost is trouble-shooting.  Everyone is using the same software, meaning that if a problem does present itself, finding a solution is usually easier.  Chasing ghosts rarely occurs as the same company that produced the avionics suite produced the aircraft flight model.

At this stage, you may think that ProSim737 only works with their dedicated aircraft.  This is incorrect; ProSim737’s avionics suite will work with numerous aircraft models including the default FSX 737 and the PMDG FS9 737, however, if you want to achieve harmonious inter-connectivity with the avionics software, then using the dedicated flight model is highly recommended.

Hello JetStream 738

The JetStream aircraft is more a flight model than an actual virtual aircraft.  Don’t expect to see “wow” factor visuals with this model.  Instead, expect to experience “wow” factor flight dynamics that work in perfect unison with the flight avionics software.

Virtual pilots using a fully developed simulator often do not need what is offered in many aircraft models: virtual flight decks, pop-up gauges and GPS consoles are not necessary.  As such, the JetStream doesn’t provide these additives.  You will, however, see the default FSX panel layout of the B737.  This can easily be permanently removed by either editing the panel.cfg file or removing the panel images.  

Installation

The JetStream software comes with an .exe installer.  Installing is as easy as following the prompts.  When installed, a JetStream 738 folder will be found in the simobjects/aircraft folder.

JetStream Textures

The Jetstream uses the default texture pack belonging to the B737-800 FSX aircraft; therefore, the outside views mimic the same texture details seen on the default FSX model.  

I think the outside textures (especially with a repainted airline livery) are just as good as many payware add-on aircraft textures.  Certainly, PMDG NGX textures surpass the JetStream textures, but you must remember that the aircraft has NOT been designed as a pretty aircraft to look at, but a flight model to replicate defined flight dynamics.  Think of it as flying ones and zeros.

Video Makers & Virtual Airlines

Video-makers or those who wish to mimic a particular airline can easily re-texture the aircraft skin to reflect a specific colour scheme or airline livery.  Search through the ProSim737 forum and you will find several dozen repaints.  Installing additional textures is identical to the method used in FSX.

If you search this website you will find mention of the 164 liveries pack.  This pack provides many liveries and re-textures.

Outside Views & Animation

Many individuals concern themselves with the outside view of an aircraft.  Whilst it’s enjoyable to inspect the aircraft from the outside, the quality of the external visuals has absolutely nothing to do with the way the flight model behaves.                    

This said, the movement of essential equipment can be observed: the rudder, flaps, ailerons, spoilers and landing gear.  Landing and other outside lights are also replicated including a functional taxi light which is bright enough to “read by”.  The outside view is far from sterile.

Taxi Light – Too Bright & Intense

One downside to the external view is the actual positioning the taxi light.

Historically, Micro$oft have never animated the taxi light correctly.  ProSim737 have created their version of a taxi light, which is more a ball of light than a taxi light.

The taxi light is bright – very bright.  On lift off, the fall of the light beam covers the lower portion of the front screen view.  This obviously does not occur in a real aircraft.  Although I have not altered the files, I have been informed that this cosmetic issue can be rectified with a small tweak to the aircraft.cfg file.  

I would have liked ProSim737 to have developed the external lights from scratch with a dedicated taxi light with no fall off on the lower portion of the computer monitor.  Good external lights are essential if you fly predominately at night.

Flight Dynamics – flying Ones & Zeros

This is why the JetStream was developed – as a platform to replicate complicated flight dynamics to realistically mimic the movement and handling of a real jet aircraft.  This is where the wow factor begins and is where the JetStream leaves it’s contemporaries behind.

I am very impressed with the flight dynamics.  During several hours flight testing, the model was exceptionally stable, handled as you would expect, and interfaced with the ProSim737 logic flawlessly.  

Fine-Tuning & Stability Testing

ProSim737 has been designed to be operate with MCPs (Main Control Panel) manufactured by several companies.   I have been informed that, depending on the MCP type, problems can be experienced with the sensitivity of the auto pilot.  To alleviate this, ProSim737 allows the sensitivity of the MCP to be adjusted.

The JetStream manual suggests that a good method to determine possible over-control (i.e. oscillations) is to increase the simulation speed to 4x and observe if oscillations occur, and if the autopilot is able to hold either heading or altitude”.

I performed this stability test at x4 acceleration and noted very mild pivoting of the wings as the aircraft slewed along it defined navigation track.  When I morphed back to normal speed, the aircraft was in the same direction, attitude and altitude that it was when I entered acceleration mode.  Only at faster acceleration speeds (x16) did the aircraft loose position (which is to be expected).

Hardware Calibration

The JetStream requires careful and fastidious calibration of your yoke and rudder pedals to ensure solid performance.  

Calibration isn’t as important if you use the auto pilot to do most of your flying, however, if you prefer to hand fly to and from FL10, correct calibration of your yoke and rudder is paramount.

It’s essential to take the time to calibrate your hardware correctly using the Windows and FSX calibration tool, using FSUIPC to fine tune the results.

Your hardware control settings play a huge role in how the plane behaves, so before blaming the flight model, please test it with different controls and settings.  

The following is an excerpt from the JetStream read me file:

  • Most 738 models available represent a truly overpowered engine/dynamics ratio, The flight model tries to follow the real curve, don't expect it to reach high speed/AOA values as other flight models do, especially immediately after rotation.

  • As in FSX, nose-steering is nothing else but rudder, without FSUIPC's given steering routine and a hardware wheel, do not expect acceptable results on the ground.

  • The VC was deliberately removed from the model.

  • Trim related values do depend on hardware behaviour.  This relates to whether hardware has been calibrated with or without FSUIPC.

  • Idle N1 value is OAT dependent. You will get 20.7 at 15C.

  • Set General Realism Slider to Maximum! It is vital for the model!

PMDG (FS9) and Default 738 Verses JetStream

I outlined in the opening paragraph that ProSim737 can be used with several other add on aircraft, including the default FSX 738.  My limited testing proved that these aircraft fly well with ProSim737, however, nuisances do occur and tweaking of the aircraft .cfg file is needed to solve niggling problems with often undesirable outcomes..

The JetStream was designed from the bottom up to be the flight model for ProSim737.  Therefore, many of the nuisances observed when using other flight models do not exist.

As an example, the FS9 version of the  PMDG aircraft at Vr, with the yoke pulled to aft position, exhibits a slight delay of a second or two before actually lifting off the runway.  A positive rate is rarely achieved before V2 is called.  This is completely different with the JetStream which is far more responsive.  Pull back slightly on the yoke at Vr and the aircraft is airborne before reaching V2.

No matter what I did with the PMDG flight model, the only way to achieve rotation at Vr was to pull back on the yoke a few seconds before actually hearing the Vr call out.

This is but one example, illustrating why it’s solid sense to link a dedicated flight model to a specific avionics software suite to achieve harmonious integration.

FS Add Ons - Top Cat Compliant

Many virtual pilots use a popular add on flight tool called Top Cat.

Top Cat is used, amongst other things, to calculate weight, takeoff and landing performance.  The JetStream is compatible with Top Cat and the JetStream manual explains how to incorporate this advanced FS add on.

JetStream User Manual

A detailed user manual is included which is well written and informative.  It’s important to read this manual to ensure you get the most from the JetStream flight model.

Updates & Improvements

ProSim737 currently produces one aircraft and one avionics software suite.  While some may find this lacking, I find it reassuring.  Rather than become tired down to developing other aircraft and software, ProSim737 focus their attention on one aircraft – the B738.  This translates to regular updates and improvements which can only benefit the end user.

Support

Support is provided either by a dedicated forum or via personal e-mail communication.  

To date, all requests have been answered quickly and efficiently.  If you need help, support is available.  You are not left to feel as if you’re withering on a vine, waiting for assistance.

I try to be impartial and accurate when I make a review, however, if I have missed something or have made a mistake, feel free to make a comment.

This review is based solely on my experience with the JetStream and ProSim737.  I have no affiliation with the company.

My Rating is 9/10

ProSim 737 Glass Cockpit Avionics Suite - Review

prosim 737 version 1 opening screen

The ProSim737 Glass Cockpit Suite is software developed solely for the Boeing 737-800 aircraft and replicates the avionics required for the operation of the flight deck. ProSim737’s beginning was meager, however, the ongoing development, accuracy, functionality and above else, ease of use and reliability, has ensured that ProSim737 has an exceptionally strong following.  

The developers are based in Luxemburg which is why many users of the software are European based; however, flight simulation transgresses geopolitical boundaries and many users of ProSim737 are located in Asia, Australia, New Zealand and North America.

I’m not going to duplicate what can easily be read in the ProSim737 user manual.  The manual outlines much of what the software can and cannot do and I urge potential buyers to read it.

This review pertains to software release Version 1.

First Off - Caveat Emptor (Latin for buyer beware)

Before continuing, there are several flight avionics suites currently available on the market.  They all replicate the basic avionics functionality of the B737.  However, not everything is operational within each suite, and some functions behave differently between suites.  Therefore, it’s a good idea to research what works and what doesn’t before your purchase.  I have a written an earlier journal post addressing this.

Avionics Suite – The Heart

The heart is the most important organ in the human body.  Likewise, the avionics suite is the heart of the flight simulator, and provides the interface for instrumentation to operate.  If the software used is not reliable, robust and well tested, then problems may develop which ultimately will lead you into a minefield of frustration and confusion as you attempt to unravel the intricacies of the Boeing avionics system.

ProSim737 – Overview and Detail

ProSim737 is a complete avionics solution providing the ability to support all displays and logic found within the B737-800.  The software has been designed to run on one or multiple PC's in various configurations interfacing with FS2004 (FS9) or FSX, via a paid and registered version of FSUIPC.  Wide FS is not required, however can be used if networking other add- on programs.

To achieve this, the software is segregated into four broad modules: PS737 System, PS737 Display, PS737 MCP, and PS737 CDU.  Additional modules are PS737 Audio and PS737 Panel. 

I’ll discuss the details of each briefly.  For a more though dissection, I direct you to the ProSim737 website or user manual.

A short video at the bottom of this post will guide you through the various menus of the ProSim737 Systems Module.

PS737 Systems Module

The Systems Module is the main component of the ProSim family and it’s within this module that configuration of the switches, indicators, drives, and gauges occur.  In addition to providing the detailed logic to replicate the following aircraft systems and components: electrical, pneumatic, fuel, hydraulics, heating, fire detection, IRS and master cautions, the module provides access to a web-based instructor station and server that other ProSim737 modules connect to and from.

The Systems Module, because it houses the server, must be installed on the computer running flight simulator.  Likewise, for any other module to operate, the Systems Module must be opened.

PS737 Display Module

As the name implies, this module supports the main visual displays located in the Main Instrument Panel (MIP) that a pilot views when in the flight deck.  The module also provides several additional “virtual” gauges, such as clocks, stand by instruments and a flaps gauge for those flight deck builders who don’t use reproduction hardware gauges, or converted real instruments.

The following displays and gauges are included in the display module.

  • Captain and First Officer Pilot Flight Display (PFD) and Navigation Display (ND) -  various      configurations

  • EICAS display (upper & lower) with fully integrated EICAS messaging

  • Virtual Main Control Panel (MCP)

  • Virtual EFIS display (two)

  • Virtual overhead panel (forward & aft)

  • Virtual CDU display

  • Virtual stand-by instruments (good selection)

If you’re operating a full flight deck with appropriately supported hardware you won’t require the virtual MCP, EFIS, CDU and overhead displays.

prosim 737 virtual mcp

ProSim737 MCP Module

This module controls the Mode Control Panel (MCP) which is the auto pilot system in the aircraft.  The MCP communicates with the logic coming from the systems module to provide information regarding altitude, direction, speed and other auto pilot constraints.

ProSim737 allows the user to either configure the MCP as a “virtual” MCP panel displayed on a computer monitor, or for builders using a hardware MCP, display minimised.  The virtual MCP includes two Electronic Flight Instrumentation System (EFIS) modules in either Honeywell or Collins configuration.

This MCP module usually resides on the same computer as the systems module.

ProSim737 CDU Module

The Control and Display Unit (CDU) is used to assess information from the Flight Management System (FMS).   A user can either use one, two or any number of instances of the “virtual” CDU and each will display identical information.  If a hardware CDU is being used, there is the ability to turn off the “virtual” CDU and display the data on the hardware unit.  All CDU instances are linked to each other via the ProSim737 Systems Module.  It’s usual practice to install and run this module from a client computer.

ProSim737 Audio Module

The audio module is a stand alone module that allows user customised sounds to be played when various preset functions occur, such as when switches are toggled, speeds are reached, etc.  This module is needed to allow GPWS and TCAS cautions, in addition to V1, V2, Vr and altitude call outs.  The module can be installed and run from any computer and links to the ProSim737 systems module.  The module runs as an additive to ProSim737’s internal sound (located in the Systems Module).

The virtual forward overhead panel.  Many switches are functional and can be moved with the mouse

ProSim737 Overhead Module

This module provides the switches, gauges and dials for the forward and aft sections of the overhead.  The module is installed on the client computer and is usually left open full screen, unless you have a hardware overhead installed.  The module supports functionality essential to the basic operation of the B737.

Reliability, Robustness & User-Friendly

When you evaluate a product, it’s “usually” fairly easy to find inherent problems.  ProSim737 is a different beast; since I began using their software I have not had any problems that suggest inherent problems with the underlying software framework.  It’s a pleasing experience when you open software and it “just works”. 

Of course, variances between computer systems and a wide variety of FS add on programs, can cause minor nuisances to occur – this is normal with any software.

To avoid any issues, I advise that all flight simulator add on programs be removed before evaluating a software suite.  Once you’re happy that everything is functioning as it should, add each FS add on in turn, checking to ensure correct operation.  If a problem does occur, at least you will know which program is causing the issue.

ProSim737 is an exceptionally robust software platform and the program has never crashed despite me changing configurations, etc “on the fly”.  

Software Installation

Simplicity and easy of use are the mantra of the developers of ProSim737.  Opening the ProSim737 package will reveal a number of appropriately named folders.  To install the Systems Module you click an executable file and install to the computer on which flight simulator is installed.  The other folders are then copied to the client computer.  IP addresses must be known to allow communication between modules across the network.

You don’t have to open .ini files or configuration files during installation and you don’t need to copy and paste files between folders.  Basic configuration is achieved by right clicking the mouse which opens a configuration screen.  The set-up is uncomplicated and is logically set out.

The only files you need to cut and paste to a folder are the terrain files and navigation database.  Detailed instructions on how to do this are documented in the comprehensive and well-written manual.

prosim 737 Configuration display when using right mouse click - everything is easy to find and configure with minimal time outlay

Learning Curve and Ease of Use

Any new software has a learning curve; however the curve is very shallow when using ProSim737.  You don’t have to be a programmer or have in-depth computer knowledge to install or use ProSim737.  The software is very easy to install, configure and maintain. 

For example updates, which are frequent, do not require you to manually cut and paste a new version download to several folders.  An update button within the Systems Module completes the update task within minutes.  As you open other modules, they each in turn are updated from the Systems Module.

Another example, which shows the ease of use relates to the configuration of various displays provided in the ProSim737 Display Module.  To set-up a dedicated display, you mouse drag the required display to the monitor of choice and then right click the window to open the configuration menu; resizing the display is done using the mouse.  To avoid the problem of the display accidentally changing size in the future, you tick the “freeze constraints” box. It literally takes less than 10 minutes to establish the visual displays in the flight deck!

Configuring Your Switches and Buttons

Configuring buttons and switches to your set-up relatively uncomplicated involving opening a menu in configuration mode, scrolling to find the particular function you need, and then connecting the output type to a specific output.  Granted there is a learning curve, but the curve is low and essential tasks don’t requite extensive knowledge of computer code.  

Similarly, customised audio files can be added, linked and played in the Audio Module.

Navigational Database and Terrain Files

ProSim737 does not provide the navigational database that is needed by the aircraft.  This must be purchased as a separate item from Navigraph.  This is normal practice and all developers rely on Navigraph to maintain the latest navigation package. 

Installing the database requires you download the data and then extract the data, via an executable file, to a specific folder within ProSim737.  You then must build the database which is achieved by pressing a button within the configuration menu.  

Similarly, the terrain files must be downloaded from the ProSim737 website and manually copied to the appropriate folder.

Driver & Hardware Support

Today, there are several vendors ranging from high end to budget level that are replicating B737 hardware and instrumentation.  ProSim737 development is forward based, meaning they understand the need for avionics software to be compatible with as many hardware types as possible.  Flight Deck Solutions, Engravity, Go Flight, CP Flight, SISMO and Open Cockpits are all supported and several types of I/O cards are supported such as Pokey, FDS SYS and phidgets.  FSUPIC and FSUPIC offsets are also supported by ProSim737.

Determining which hardware is selected for your set-up is as easy as checking a box within the configuration screen of the Systems Module.  

Accuracy and Resolution of the Flight displays

You spend a lot of time staring at the various displays, whether it’s the Pilots Flight Display, Navigation Display, CDU or EICAS; therefore, it important that the graphics are of the highest quality possible; nothing is worse than staring at jagged corners, off-putting colours, or blurry lines.  

Although the quality of any graphics is linked to the resolution of the computer screen, if you use a high resolution screen you will not experience any anomalies associated with poor graphics.  The display graphics are crisp and sharp. 

  • To see images of displays navigate to the ProSim737 website.

All simulation enthusiasts strive for accuracy; some to a greater extent than others.  The displays depict what you would see if you were looking at the displays in a real B737 main instrument panel.  Only the very keen you will note the odd subtle difference between the simulation and the real display, and this is often determined to a certain extent, by the cockpit set-up and carrier options you select from within the instructor station.  

For example, the magenta course line in the Pilots Flight Display appeared to be slightly thinner than on the real aircraft, but no sooner had I noticed the disparity that Marty at ProSim737 had uploaded an update rectifying the issue.

What’s important to realize, is that the developer listens and if inaccuracies are noted rectifies the disparity quickly and without argument.  

ProSim 737 Screen grab showing variations of PFD and ND displays dependent on EFIS setting

Precision

Any software must provide precise outputs when its logic is queried; all virtual pilots demand that software outputs be precise in execution.  To date, ProSim737 has lived up to its reputation and I cannot highlight any major downfall in the precision of the software. 

ProSim 737 Screen grab showing variations of PFD and ND displays dependent on EFIS setting

Vertical Navigation (V-Nav)

A common thread in FS forums is that avionics software has difficulty in replicating Vertical Navigation (V-Nav).  This is especially evident with software supplied by Project Magenta and to a limited extent with Sim Avionics. 

ProSim 737 Screen grab showing variations of PFD and ND displays dependent on EFIS setting

The logic used to replicate V-Nav is not simple; it’s complicated, and the variability in V-Nav usage often causes issues to develop when using V-Nav.  The main problem is that the aircraft may not keep within the constraints entered into the CDU.  Often the aircraft will either over fly an altitude constraint or not maintain a entered speed constraint.

From the outset, V-Nav in ProSim737 has worked exceptionally well.  Altitude and speed constraints, if entered correctly, are maintained and the reliability of V-Nav surpasses those of other software suites I have used.

V-Nav Usage

V-Nav, even to qualified pilots can be a challenge to use correctly.  This is one reason why V-Nav should only be used as a guide and not as an absolute.  If V-Nav, for whatever reason does not function in a method you think is correct, then turn it off and use the more reliable L-Nav, Level Change or Vertical Speed functions.

The challenge, I have discovered when using V-Nav is two-fold.  First, you must use it within the designed capabilities of the program, and two, you must learn how and when to operate V-Nav.  If you enter data that the FMS cannot assimilate, such as an altitude that is too high or too low, for the time required to reach the waypoint, then expect an over fly of the entered restrictions.  This is not the fault of the software, but the fault of the user.

Display Lag

Display lag is term coined to explain the staggering of a display due to information overload, information bottleneck or lack of computer graphical power.  It typically manifests itself when a lot of information is required to be displayed at an identical time that computer processing is required.

For example, another software suite I have used displayed staggering on the altitude tape in the Pilots Flight Display (PFD) when ascending and descending with the “all waypoints” selected from the EFIS.  The staggering stopped when the “all waypoints” were deselected.

I have yet to experience any display staggering with ProSim737, even with the terrain simulation display activated.  

Weather & Terrain Display Functionality

The weather and terrain display function, which is activated either by pressing WXR or TERR on the EFIS unit is functional in ProSim737, however, the weather display is inaccurate and looks very outlandish in its “blocked in” colour display.  

I’m lead to understand that the weather functionality present within other software (Sim Avionics), reads directly from weather depicted by FSX, and then only presents a rough indication of what the weather maybe like at that particular time; it certainly does not mimic and display what the aircraft is actually flying through or about to fly through.  

I am hoping that the developers at ProSim737 will develop a radar module that actually reads the exact weather depicted in FSX and display this weather in a way that is similar to the real radar in the B737.  At the time of writing, the weather displays only in solid colours and does not mimic how real radar operates.  I hope that ProSim737’s developers improve this in due course.

ProSim 737 terrain files (two choices)

Two Terrain File Resolutions

Pressing the terrain (TERR) button on the EFIS unit, displays a graphical representation of the surrounding terrain on the Navigation Display.  There are two variations of the terrain graphics available; one display is slightly blocky and the other display is more detailed.  To select which display is active, right click the screen with your mouse and tick the appropriate box in the configuration menu.


Compatibility of Aircraft with ProSim737

It's always been a concern to what add on aircraft you can use with a particular avionics package.  As an example, Sim Avionics provides several aircraft .cfg files which have been tweaked to their software.  You load the particular aircraft.cfg file for the aircraft you are using and any vagrancy between the aircraft and avionics software is rectified.

ProSim737 has taken a completely different approach and designed a flight model called the JetStream 738, which is tweaked to operate flawlessly with ProSim737.  Of course, you don’t have to use the JetStream if you don’t want to; the default B737 can be used as can the PMDG B737 FS9 version with flight logic removed.  

I will review the JetStream738 in a separate journal post.

CDU - Background Software

No review of any avionics software is complete without a short segment on the CDU.

The ProSim737 CDU module is the controlling software that provides the intelligence behind the CDU.  It's amazing what this software can do, and do so with reliability and consistent behaviour.  More importantly, the software does not crash, even when incorrect data is inputted to the unit.

Many pages associated with a commercial CDU are modelled and updates continue to add new features and improve existing functionality. 

In the real B737 aircraft, not all CDU software is identical.  There are different software versions and each version has slightly different functionality; it’s the decision of the airline to which software version is chosen.  Likewise, not every company producing avionics software models the CDU identically.  In some respects, it depends on which software edition the developer has chosen to replicate. 

Unfortunately, many developers choose to not replicate something or to not provide full functionality.

Often CDU menus and pages may look similar in appearance, but you will be disappointed when trying to access a feature that appears to be modelled but has no functionality.  Some suites offer far greater functionality than others.  I believe ProSim737 provides more functionality than other higher end CDU software available, and more functionality is regularly added through software updates.

Some of the basic features modelled by the CDU software are:

  • Indent page on start-up (weights, fuel, fuel reserves, cost index, cruise altitude, etc)

  • Approach reference page with VREF selection

  • Route, LEGS, Arrival, Departures & Holding pages (user controlled including approaches, STARS, SIDS & transitions)

  • Progress pages (fuel, distance to go, ETA, wind, crosswind component, cross track error, fuel prediction etc)

  • Vertical Bearing Indicator (VBI)

  • V-Nav & L-Nav compliant (climb, cruise and descent)

  • Ground Service - push back

  • NAV/COM radio reference page (ADF, ICAQ, VOR & ILS data) & search

  • ACARS (future installment)

  • Captain & First Officer EFIS control

  • OAT

  • SIM MAINT page (separate commands to control SIM instead of using keyboard) such as pause, freeze & re-set FMC.

The software lacks the ability save a flight plan directly from the CDU; you must use the instructor station to save a flight plan. Also, it’s not possible to reverse a route from the CDU.  It would be helpful if this functionality can be implemented.

The software is compatible with CDU hardware produced by Fly Engravity and Flight Deck Solutions.

prosim 737 ios showing CAT visibility and push back & failures menu

Instructor Station

The instructor station included with the software is a web-based station, meaning you type in the appropriate address into the browser web bar and the instructor station opens on any computer connected to your network – even a laptop.  No other software is needed.

The instructor station is comparatively simple in layout, yet functional.  Without repeating the user manual, which outlines in detail what each section comprises, the station displays the following menus: Quick Start, Cockpit Set-up & Carrier Options, Global Database, Situations & Positions, Company Routes. Flight Plans and Failures.

prosim 737 ios failure screen

Two Instructor Station functions  deserve mention

Company routes allow you to store and manipulate routes you have loaded into a specific folder within ProSim737.  These routes, if not manually built using the CDU and FMS and saved to the instructor station, are usually downloaded from on-line route generators.  As the station has a built in editor these routes can easily be edited and re-saved.  You can also download from the station to the CDU any selected route.

The situation menu I find particularly useful.  Here you can instigate push back, execute day or night and switch to real time at the push of a button.  You can also define visibility as CAT I, CAT II or CAT III.   This can be done on the fly while the aircraft is flying.

The failures menu can be set-up to allow any number of single, multiple or cascading failures to occur either within a predefined time or at random.

ProSim737 Start-up Sequence

Ease of use and simplicity are important to ProSim737 and this mantra is carried through to the operation of the software.  Opening the ProSim737 Systems Module and other associated modules is exceptionally fast and the programs close with minimal lag time.  This is in stark contrast to other software suites which seem to take an eternity to open the various instances of the same program.

To simplify the start-up process when opening a flight session on my two networked computers, I’ve created shortcuts to the required ProSim737 modules and pasted them to the windows menu bar.  This is my start process (included are some add on programs I am running).

Server Computer

  1. Start PM Sounds

  2. Start ProSim737 main module

  3. Start ProSim737 MCP module

  4. Start ProSim737 Audio module

  5. Start FSX

  6. Start FSRAAS2

  7. Start Throttle Quadrant Phidgets

Client Computer

  1. Start PM Sounds

  2. Start ProSim737 Display (Captain PFD& ND)

  3. Start ProSim737 Display (First Officer PFD & ND)

  4. Start ProSim737 Display (EICAS)

  5. Start ProSim737 CDU

  6. Start ProSim737 Overhead Panel

  7. Start ProSim737 Audio module

  8. Start ProSim737 web-based instructor station

The time to start each program is no longer than 4 seconds; FSX takes the longest time to load.  Closure time is similar (mouse right click/close) from the menu bar.  To decrease closure times and mouse movement, a closure batch file can be created.

What is lacking & Possible Improvements

There will probably always be something lacking no matter what software you use, and some enthusiasts are never happy until they have everything – even if they never use or need it.  

The Aircraft Communications Addressing and Reporting System (ACARS) is not supported, although I believe this will be addressed in future updates.  I’ve already discussed some missing functionality with the CDU and touched on the inadequacy of the weather radar.

For the most part, all essential functionality is present within the system, although it would be nice to have more CDU functionality and a list of functions the CDU is capable of.  Currently no such list is available, and if using an official FMC guide it can be "hit & miss" working through he menus to see what is functional.

Several users have commented on the forum, that the %CG calculation in the CDU usually remains the same despite changing the aircraft's overall weight.  Users of TopCat pre-flight software have reported variances in %CG between ProSim737 and TopCat.  This variance may suggest an issue in the calculation of %CG which needs fine-tuning.

The list of hardware supported by ProSim737 is long and continuing to grow.  This said, I have noticed that the CP Flight ATC/Transponder unit which supports full TCAS operation is only partially functional within ProSim737.  TA/RA is inoperative.  Although the responsibility for this incompatibility probably rests with CP Flight, it would be very nice if ProSim737 attempted to rectify this.  CP Flight hardware is used universally and full functionality should be implemented across the complete CP Flight range of hardware.

Continual Development

In my opening paragraph I stated, “Avionics software is the heart of the simulator”.  Therefore, it’s pleasing to see continuing development of the software; updates that add or improve on existing functionality are released on a very regular basis.  Furthermore, the software designer is open to suggestions from users on how to enhance the software.  Shortcomings, when observed are quickly addressed.

One Aircraft - Mono Focus

One very important attribute of ProSim737 is that the developers only produce software for the B737 aircraft.  This means that they focus 100% of their time on replicating this airframe.  Other companies develop software for multiple aircraft and try to incorporate duel systems within their software.

Compromise & Expectations

It’s a fact that human beings rarely enjoy compromising – we want everything and we want it now. 

Some of you maybe "thinking" that ProSim737 has issues that need rectifying.  I'd be lying if I told you everything was 100% perfect - of course there are issues, but these are minor and differ depending upon your set-up.   But, in comparison to other software suites on the market, I feel confident stating that ProSim737 has less issues and rectifies niggling problems much more quickly than their counterparts.

If your expectation is to have software that is absolutely perfect without any glitches at all, then I'd strongly suggest that building a flight simulator is not really your calling. There are so many variables with computer equipment, drivers and the like that minor issues will pop up from time to time.

Developing software that replicates the B737 avionics to the tenth degree is a noble thought, as is maintaining a reasonable price.  However, what builders often fail to remember is that the Boeing software cost millions of dollars to design and implement with a solid team of developers.

ProSim737 delivers an exceptionally good package that is more advanced and feature-rich than its counterparts.  It’s not perfect, but the developers strive for perfection and improvements continually are being released on a regular basis.

Documentation and Support

The definition of osmosis is; “The gradual, often unconscious, adsorption of knowledge or ideas through continual exposure rather than deliberate learning”.  In the previous software suite I used, “osmosis” was very much the method of learning, as were mistakes, wasted time and frustration.

It’s good to see that ProSim737 includes a very detailed and well-written instruction manual which explains how to do nearly everything you need to know to configure the software to your set-up.  Failing this, there is a dedicated interactive forum that is very regularly reviewed both by users, beta testers and ProSim737 staff. 

If a problem does occur, support can be reached either by Private Messaging or e-mail.  

You will not be left “high and dry” by the developers.  They are very enthusiastic about their product and keen to help wherever possible.

A short video will guide you through the various menus of the ProSim737 Systems Module.

 
 

Recommendation & Overall Score

ProSim737 is a stable, well tested and tried software platform that provides most of the real-world avionics of a B737 jet-liner.  The software is easy to install, use, and does not require advanced computer knowledge to get you in the air.  Furthermore, a vast collection of hardware and interfacing cards are supported and new functionality is added on a regular basis.

At the time of writing, if you purchase ProSim737, the software includes full support and updates for an unlimited time period. 

This has been a long post, and if you have read this far, I hope you have gained some incite into ProSim737.

To download a free trail version of the software, visit their website – ProSim737.

My Rating is 9.5/10

Please note that this review is my opinion only and is not endorsed.

Update

on 2014-02-12 23:38 by FLAPS 2 APPROACH

  • Please note that since this review has been written, ProSim737 developers have released several updated versions of the software and three incarnations; Version 3 being the latest (2024).

  • The content of the review is outdated and has been left on the website for historical interest.

Construction Commenced - New Platform to Install OEM Control Columns

I thought it time to post what’s happening with regard to the construction of the simulator.  Additions and improvements are in the pipeline and it’s hoped that OEM control columns and a new platform will be installed very shortly.

Currently the simulator is mounted on a fiber-board and wood platform, which I constructed when I received my Main Instrument Panel (MIP) just before Christmas 2010.  The platform has served me very well and was perfect for the installation of the ACE yoke and Precision Flight Controls (PFC) rudder pedals.  

Soon after constructing the platform and purchasing the ACE yoke, I was able to secure two OEM B737-500 control columns. I was surprised to find these units so quickly and I was fortunate that my timing coincided with the dismantling of a late model B737-500.

Fitting the OEM control columns to the wooden platform appeared to be problematic, as the platform was a tad low in height and it was awkward to retrofit the linking rod that connects the control columns for duel operation.  Therefore, I decided that a new platform was required; custom designed  to fit the control columns.

Aluminium Modular Design

Rather than use wood and fiber-board, I selected aluminium tubing cut appropriately and TIG welded together.  To facilitate future transport, the platform has been constructed in modular form.  The forward portion comprises three modules bolted together in strategic places, while the rear part of the platform (not shown), where the seats and center pedestal reside, abuts snugly to the forward section.  It’s intended to use high density ¼ inch plastic/vinyl as the upper cover on the platform  as this material is easier to work than aluminium sheeting, is light in weight, very strong and comes from the factory in Boeing grey.

In the photographs (click to enlarge) you can see the control columns (striped completely) fitted to the forward modular section of the platform.  The control columns are connected to each other by a ¾ inch heavy duty shaft and heavy-duty double bearings.  Forward and aft movement of the control column is controlled by a heavy duty spring and left and right roll movement is controlled by another spring. 

Control Column Pull Pressures

The pull pressure on the control column is set to 24 pound which is slightly less that the standard pull in the B737 which is 34 pound.  The pull can be easily altered by moving the spring forward or backward on the spring retainer.  The pressure on the roll component is presently 12 pounds.  I've been told the roll pressure as per the Boeing maintenance manual is +_15 pound; therefore, I'm well within the ball park.

Throttle Thrust Problem - Loosing Thrust at N1 - The Solution

oem 737-300 throttle

The throttle installed into the simulator is a converted genuine B737-300 throttle.  Lately, I have observed inconsistent power thrust issues during the take off roll and climb out. 

As I begin the take off roll, engage TO/GA and rotate, but before acceleration altitude or acceleration height is reached, one of the throttles looses or gains power.  Moving the throttle handle reinstates throttle power, but the power is dependent on where the actual throttle lever is physically positioned. 

When the aircraft is above thrust reduction altitude (1500 radio altitude) the problem rectifies itself.  The problem cannot be replicated when flying above 1500 feet.  I also noted, and this may also be part of the issue, that the power indicators located on the EICAS display fluctuate (twitch) a little as I moved the throttle levers.

This problem only began to occur after I transferred the avionics software to ProSim737.

Process of Elimination

Problems like this are not uncommon when interfacing real aircraft parts and the challenge is finding the cause of the problem.  The only method to determine solutions to problems such as this is to systematically, through the process of elimination, identify the problem area.

My first thought was that one of the potentiometers in the throttle quadrant maybe damaged, although I considered this to be unlikely as the units are still relatively new.  The throttle has four potentiometers: throttle 1, throttle 2, flaps and spoilers. Flight testing indicated that the power loss alternated between engine 1 and engine 2; therefore, the likelihood of two potentiometers failing at the same time was minimal. 

The next step involved checking the wiring within the throttle quadrant, to ensure there wasn’t damage to the outer coating of the wires.  A damaged or loose wire can easily short on the throttle frame and generate a spike.  However, if the wiring was loose or damaged, the problem would also occur when flying at altitude, and I had clearly demonstrated that the problem only occurred during the take off roll and climb out to thrust reduction altitude. 

The next step was to ensure that calibration of the throttle unit was correct.

Re-Calibration Using FSUIPC

I decided to re-calibrate the throttles using FSUIPC rather than FSX.  This process isn’t difficult and FSUIPC allows you to fine tune each throttle with greater accuracy than is possible with FSX. 

After re-calibration, the “twitching” of the power indicators ceased, but the initial problem remained.

The Cause of the Problem

The only culprit I could think of to cause this problem was ProSim737.

To check whether ProSim737 was actually the cause of the problem, it is necessary to remove any input from the ProSim737 software.  This is straightforward.  Either use another avionics software package or use FSX itself.  I did twenty trial flights using both Sim Avionics and FSX and the problem did not replicate. 

ProSim737 Excellent Support and Advice

I contacted the developers at ProSim737 explaining my problem in detail, and I received a response to my questions within a few hours.  Marty was especially helpful and we discussed several potential reasons for this issue and possible workarounds.  I must stress that the response I received from ProSim737 was absolutely 100% top notch. 

Marty genuinely wanted to help resolve the issue – whether it be with ProSim737 or otherwise.

Real B737 Throttle Operation

Now this where the comment “as real as it gets” does have meaning…. 

The developers of ProSim737 have designed their software to replicate the logic used by the real B737 auto throttle.  The software (ProSim737) is doing exactly what it’s supposed to do in relation to power thrust, and the issue I was experienced is caused by using a real aircraft throttle without automation.  Let me explain.

In the real aircraft, when TO/GA is enabled, the auto throttle logic has control of the aircraft.  The throttles are off-line and power thrust cannot be manipulated by the pilot.  The flight mode annunciator (FMA) illuminates N1. 

As 84 knots is passed the FMA changes from N1 to THR HOLD.  At this time, the actual throttles come back on-line, meaning that you can manually alter throttle power by moving the levers.  After rotation and at 800 radio altitude the auto throttle system is ready to change from take off power to climb power and the FMA changes from THR to ARM.  When in ARM mode the throttles are still on-line. 

When the aircraft reaches 1500 RA which is the thrust reduction altitude, the throttles go off-line and the AT logic is controlling the power thrust of the throttles.  The FMA changes from ARM to N1.

Throttle Anomaly

The B737 does not have a manual throttle, but an automated throttle.  The software is programmed to move the throttle levers to the correct position mimicking the actual power thrust called for by the auto throttle logic.

If you use a manual throttle (genuine or otherwise) the connection to the automated physical movement of the throttle levers is missing; you must counter this by moving the levers yourself.  This issue should not occur with a correctly calibrated automated throttle.

Using an Auto-throttle

If you have an auto throttle, the levers will automatically and physically move to the indicated thrust position as determined by the auto throttle logic (90%N1 at TO/GA).  When the FMA illuminates THR HOLD at 84 knots, and the throttles come back on-line for possible pilot intervention, the auto throttle logic will not sense any change in the throttle lever position, and power thrust (90%N1) will be maintained.   This is because the automated system placed the throttle levers in the correct position when TO/GA was initiated.

Using as Manual Throttle

However, if you’re using a manual throttle, the throttle levers MUST be physically positioned at the correct location on the throttle quadrant, otherwise the auto throttle logic will sense a change in position of the levers and alter the power thrust accordingly to this new level. 

This is what was occurring in my situation.  I was resting my hand on the throttle and only advancing the levers 3/4 of the way forward.  TO/GA indicated 90%N1, but when the throttles came on-line at 84 knots, the auto throttle logic noted that the position of the throttle levers was not at 90%N1 and subsequently altered the power thrust accordingly.

The reason the issue was inconsistent is that I didn’t always advance the throttle levers to the same position, and if I did the problem did not occur.

LEFT:  B737-300 throttle quadrant converted to Flight Simulator use.  The TQ is a manual throttle meaning that the thrust levers are not automated and must be moved manually.  I have used a pencil to lightly mark the metal adjacent to the most commonly used N1 settings.  This ensures the levers are moved the correct location during take off.  Lever position is set to 90%N1 and flaps 5.

Solution – Change in Procedures

The solution to this anomaly of using a real “manual” throttle is relatively simple.

You must determine where on the throttle quadrant the various N1 power settings are and then ensure, after engaged TO/GA that you move the throttle levers to the correct position (90%N1).  In my situation, the procedure is to advance the throttle to 40%N1, engage TO/GA, and then manually push the throttle levers to 90%N1.

Thank you

I’d like to thank Marty at ProSim737.  Marty worked with me to solve the issue, which ultimately was not really a problem with either ProSim737 or my set-up, but is an anomaly of using a genuine throttle unit without automation.

Possible Update

I may update the throttle quadrant to enable automation of the throttle levers and speed brake, however, for the time being the throttle quadrant will not include automation.

Update

on 2013-04-23 23:56 by FLAPS 2 APPROACH

 

diagram 1: a clear diagram that helps explain the problem discussed in the article (thanks to frazier @ prosim737 forum)

 

Vertical Bearing Indicator (VBI) - How To Calculate A Controlled Idle Descent

vertical bearing indicator (vbi) displayed on reproduction cdu manufactured by flight deck solutions (fds)

Often you are requested by ATC to alter altitude, or must intercept a desired point in space at a certain altitude for operational reasons. There are several methods available to the pilot to initiate the change in altitude; outlined below are three methods.

A: Initiating Level Change or Vertical Speed on the MCP will activate an advancing and contracting green line arc (Altitude Prediction Line) on the CDU.  This green arc identifies the location that the aircraft will reach ,if the vertical speed is maintained, in relation to the active CDU waypoint.

B:  You can calculate the distance and vertical descent using mathematics, but this can be cumbersome and may illicit possible mistakes. 

C:  You can alter the LEGS page of the CDU keying in the new altitude constraints (this assumes you are using VNAV & LNAV.

The CDU Vertical Bearing Indicator (VBI) can help you.  The VBI is basically an angle calculator that provides "live" vertical speed information based upon a desired descent angle.  An example using the waypoint TESSI is provided.

  • Navigate to Descent page by pressing the DES key.

  • At lower right hand side of the DES page you will see the following: FPA, V/B, V/S.  This is the Vertical Bearing Indicator.

  • Key RSK3 (right line select 3) and enter the waypoint and altitude (TESSI/17000)

The VBI provides 3 fields:

  • FPA (Flight Plan Angle) is the vertical path in degrees that the aircraft is currently flying.

  • V/B (Vertical Bearing) is the vertical path in degrees that the aircraft SHOULD be flying to reach the keyed waypoint (TESSI/17000).

  • V/S (Vertical Speed) is the vertical bearing (V/B) converted into vertical speed for easy input into the MCP.

Observe the V/B.  The idle descent in a 737 is roughly 3.0 degrees (PMDG use 2.7 degrees)

Wait until the V/B moves between 2.7 and 3.0 degrees (or whatever descent angle you require)

When the value is reached, dial in the required altitude and indicated Vertical Speed on the MCP

The Altitude Prediction Line will now intersect the selected waypoint (TESSI) and the aircraft should fly a perfect idle descent to TESSI.  Note that the original altitude selected for the pinpoint in the LEGS page does not reflect the new change.

Benefits

One of the advantages in using the Vertical Descent Indicator is that the pilot can instigate an accurate controlled idle descent, following a desired glide path to the desired waypoint.  This advantage can be used in a number of scenarios:

  1. Descent from cruise altitude.

  2. Approaching the runway from a straight-in approach course.

  3. Approach the runway from base or via an ARC approach.

  4. Approaching the runway for a downwind approach.

I often use the VBI from FL10 to FAF on approach, when other constraints are not required.

Video

I’ve made a short video showing the procedure. 

In the video, TESSI has been selected from the LEGS page and downloaded to the scratchpad.  Pressing DES opens the required page where the VBI resides.  In the scratchpad, the altitude constraint is entered for the waypoint – TESSI/17000 and uploaded to the WPT / ALT section of the Vertical Bearing Indicator (right line select 3). 

If you watch the indicator you will see the V/B and V/S changing as the aircraft approaches TESSI. 

Select the new altitude and vertical speed on the MCP (17000 & 780 - or nearest numeral) and you will note the FPA begins to change, indicating the new vertical path of the aircraft.  The Navigation Display (ND) will then show the Altitude Projection Line moving towards and stopping at TESSI.  The aircraft will now descend at the nominated angle of descent until reaching TESSI.  Note that the original altitude in the LEGS page does not reflect the new change.