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Mission Statement 

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

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


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

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


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

No advertising on this website - EVER!


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

Journal Archive (Newest First)

Entries by FLAPS 2 APPROACH (207)


Throttle Quadrant Rebuild - Flaps Lever Uses String Potentiometer 

There are several ways to enable the flaps lever to register a particular flaps détente when the flaps lever is moved to that position on the flaps arc.

LEFT:  Flaps lever set to Flaps 30.  The throttle quadrant is from a Boeing 737-500 airframe. The flaps lever arc is the curved piece of aluminium that has has cut-out notches that reflect the various flap positions.  It was beneath this arc that micro-buttons had been installed (click to enlarge).

In the earlier conversion, the way I had chosen worked reasonably well.  However, with constant use several inherent problems began to develop.

In this article, we'll examine the new system.  But before going further, I'll briefly explain the method that was previously used.

Overview of Previously Used System

In the earlier conversion, nine (9) micro-buttons were used to register the positions of the flaps lever when it was moved (Flaps UP to Flaps 40). 

The micro-buttons were attached to a half moon shaped piece of fabricated aluminium.  This was mounted beneath the flaps lever arc and attached to the quadrant.  Each micro-button was then connected to an input on a PoKeys 55 interface card.  Each input corresponded to an output.

Calibration was straightforward as each micro-button corresponded to a specific flaps position.


The system operated reasonably well, however, there were some problems which proved the system to be unreliable.  Namely:

(i)    The vertical and lateral movement of the chain located in the OEM throttle quadrant interferred with the micro-buttons when the trim was engaged; and,

(ii)  The unreliability of the PoKeys 55 interface card to maintain an accurate connection with the micro-buttons.

Movement of OEM Chain

The chain, which is similar in appearance to a heavy duty bicycle chain, connects between two of the main cogs in the throttle quadrant.  When the aircraft is trimmed and the trim wheels rotate, the chain revolves around the cogs.  When the chain rotates there is considerable vertical and some lateral movement of the chain, and it was this movement that caused three micro-buttons to be damaged; the chain rubbed across the bottom section of the micro-buttons, and with time the affected buttons became unresponsive.

It took some time to notice this problem, as the chain only rotates when the trim buttons are used, and the micro-buttons affected were primarily those that corresponded to Flaps 5, 10 and 15.  The chain would only rub the three micro-buttons in question when the flap lever was being set to Flaps 5, 10 or 15 and only when the trim was simultaneously engaged.

LEFT:  First Officer side of a disassembled throttle quadrant  (prior to cleaning and conversion).  The large notched cog is easily seen and it's around this cog that the OEM chain rotates (the chain has been removed). 

The cog and chain resides immediately beneath the flaps arc (removed, but is attached to where you can see the four screws in the picture). 

Although there appears to be quite a bit of head- space between the cog and the position where the flaps arc is fitted, the space available is minimal.  Micro-buttons are small, but the structure that the button sits is larger, and it was this structure that was damaged by the movement of the chain (click to enlarge).

An obvious solution to this problem would be to move the chain slightly off center by creating an offset, or to fabricate a protective sleeve to protect the micro-buttons from the movement of the chain.     However, the design became complicated and a simpler solution was sought.

The previously used system is documented in more detail here:  B737 Throttle Quadrant - Flaps UP to 40; Conversion and use.

Replacement System

Important criteria when designing a new system is: accuracy, ease of installation, calibration, and maintenance.  Another important criteria is to use the KIS system.  KIS is an acronym used in the Australian military meaning Keep It Simple.

The upgraded system has improved reliability and has made several features used in the earlier system redundant.  These features, such as the QAMP (Quick Access Mounting Plate) in which linear potentiometers were installed, have been removed.

String Potentiometer Replaces Micro-buttons

A Bourne single-string potentiometer replaced the micro-buttons and previously used linear potentiometers.  The string potentiometer is mounted to a custom-designed bracket on the First Officer side of the throttle quadrant.  The bracket has been fabricated from heavy duty plastic.

LEFT:  Single-string potentiometer enables accurate calibration of flaps UP to flaps 40.  The potentiometer is mounted on a customized bracket screwed to the First Officer side of the throttle quadrant superstructure.  The terminal block in the image is part of the stab trim wheel system (click to enlarge).

A string potentiometer was selected ahead of a linear potentiometer because the former is not limited in throw; all the flap détentes can be registered from flaps UP through to flaps 40.  This is not usually possible with a linear potentiometer because the throw of the potentiometer is not large enough to cater to the full movement of the flaps lever along the arc.

A 'string' is also very sensitive to movement, and any movement of the string (in or out) can be accurately registered.

Another advantage, is that it's not overly important where the potentiometer is mounted, as the string can move across a wide arc, whereas a linear potentiometer requires a straight direction of pull-travel.

Finally, the string potentiometer is a closed unit.  This factor is important as calibration issues often result from dust and grime settling on the potentiometer.  A closed unit for the most part is maintenance free.

To read more about string potentiometers and their advantages, navigate to to this article: String Potentiometers: Are They Worthwhile.

The end of the potentiometer string is attached to the lower section of the flaps lever.  As the flaps lever moves along the arc, the string moves in and out of the potentiometer. 

The ProSim737 software has the capability to calibrate the various flap détentes.  Therefore, calibration using FSUPIC is not required.  However, if ProSim737 is not used, then FSUIPC will be needed to calibrate the flap détente positions.


Apart from the ease of calibration, increased accuracy, and repeatability that using a string potentiometer brings, two other advantages in using the new system is not having to use a Pokeys 55 card or micro-buttons.

Unreliability of PoKeys 55 Interface Card

The PoKeys card, for whatever reason, wasn't reliable in the previous system.  There were the odd USB disconnects and the card was unable to maintain (with accuracy and repeatability) the position set by the micro-buttons.

I initially replaced the PoKeys card, believing the card to be damaged, however, the replacement card behaved in a similar manner.  Reading the Internet I learned that several other people, who also use ProSim737 as their avionics suite, have had similar problems.

Micro-buttons can and do fail, and replacing one or more micro-buttons beneath the flaps arc is a time-consuming process.  This is because the upper section of the throttle quadrant must be completely dismantled and the trim wheels removed to enable access to the flaps arc.

Registering the Movement of the Flaps Lever in Windows

The movement of the flaps lever, prior to calibration must be registered by the Windows Operating System.  This was done using a Leo Bodnar 086-A Joystick interface card.  This card is mounted in the Throttle Interface Module (TIM).    The joystick card, in addition to the flaps lever, also registers several other button and lever movements on the throttle quadrant.  

Final Call 

The rebuild has enabled a more reliable and robust system to be installed that has rectified the shortfalls experienced in the earlier system.  The new system works flawlessly.

Acronyms and Glossary

OEM - Original Aircraft Manufacture (real aircraft part).


How to Update and Troubleshoot Problems with the ProSim737 Avionics Suite

The backbone of the simulator is the avionics suite, and for the simulator to run effectively this software must be reliable, feature rich, and robust. 

There are several avionics suites available to simulate the avionics and functionality of the Boeing 737; Project Magenta, Sim Avionics, and ProSim-AR being the most popular.  I have not mentioned Precision Manuals Development Group (PMDG), as PMDG is marketed as a desktop simulation not used widely in a hardwired simulation.

Many virtual flyers assume, that when they purchase an avionics suite, the software will replicate all the aircraft systems, be compatible with their computer and simulator hardware, and probably not need to be updated. Unfortunately, this is rarely the case.

In this article, I will discuss the use of the User Interface and Version Manager which forms part of ProSim737 avionics suite.  These two tools are used to update the software, and to enable first-line troubleshooting.  Additionally. I will share with you several ‘tried and tested’ methods to resolve update problems.  The last part of the article will address recommendations for basic troubleshooting. 

The Reason and Need for Updates

Technology is rarely static, and developers if they are to encapsulate new technology must provide updates to their products.  This evolution can be likened to a game of ‘leap frog’; as something new is released, developers ‘tweak’ their software to take into account new technology while (hopefully) still maintaining compatibility with legacy systems.   

Another reason for updates is that there is not an avionics suite that completely encapsulates 100% of all systems (and functionality) used in the B737.  A possible close exception is PMDG, but as mentioned earlier, this is a desktop simulation (I am not including Level D/Type 7 simulators).

Each company that produces an avionics suite has a specific method to how its software is installed, maintained, and lastly kept up-to-date with improvements, fixes and software upgrades.  For example, Sim Avionics beta test changes and improvements themselves (or to a select group of individuals) and then release a version update.  This is in contrast to ProSim-AR, who release a beta for client appraisal.  Then, after bugs and shortcomings are rectified, release a final release.

ProSim-AR - frequent updates

The avionics suite developed by ProSim-AR for the Boeing 737 Next Generation is feature rich, easy to install and run, and the software is for the most part very robust.   The company ‘appears’ to be committed to ensuring that their software operates across a wide range of computer hardware, and interfaces with as many mainstream hardware components as possible (for example, CP Flight, SimWorld, Open Cockpits, Flight Deck Solutions, etc.).  In my opinion, the company is very proactive in interfacing with new technology to gain the maximum benefit that new technology brings, which includes increased market share and profitability (for ProSim-AR).

With this in mind, ProSim-AR release updates to their software on a very frequent basis.  

Understanding the Basics of the ProSim737 File Structure

It is important to understand the basics to how the ProSim737 file structure is set out, as this will provide guidance to the best way to install an update, and if a problem occurs, troubleshoot.

The ProSim737 suite contains the following modules, located in a folder of the same name.  

(i)      ProSim737 (main system module);
(ii)     ProSim-CDU;
(iii)    ProSim Audio;
(iv)    ProSim Display;
(v)     ProSim MCP;
(vi)    ProSim Panel; and,
(vii)   ProSim737 Hardware Connector;

The folders can be installed to either a server (the computer that has flight simulator installed) or any number of clients (computers networked to the server computer).  Additionally, duplicate instances of the same module, with the exception of the main system and MCP module, can be installed.  

The ProSim737 folder and MCP folder must be installed to the server computer for optimal performance.  The other folders can be installed to the server or client computer, either as single or duplicate instances.

The ProSim737 folder contains the main system module and this is the module that interfaces with all other modules.

The folders can be installed anywhere on the computer, however, it’s not recommended to place them in the same folder (ROOT folder) that flight simulator is installed.

Important ProSim737 Files

Each ProSim737 folder contains a configuration (config) file.  The configuration file contains information pertaining to screen position, functionality, IP address, etc.  The most important configuration file is located in the main ProSim737 folder.  This file, amougst the things, holds the information that relates to specific hardware, functionality and button assignments.  All configuration files are named config.xml.

Other important files, located in the main ProSim737 folder, are the:

(i)     Companyroutes.xml;
(ii)    ConfigMCP.xml;
(iii)   TransitionAltitudes.xml; and,
(iv)   Cockpitsetup.xml.

The configuration files are important.  These files should be regularly backed up.

Other files that relate to the update process are the updatelog.txt and changelog.txt. The updatelog.txt contains information concerning to the latest update, while the changelog.txt provides a list of changes that has occurred in the various ProSim737 releases.   

Important Point:

  • The most important configuration file is the config.xml file located in the main ProSim737 folder.  This file contains all information that relates to configuration, customization, and hardware.  It should be regularly backed up.

User Interface and Version Manager

The User Interface enables you to customise the avionics suite, configure hardware components, update, and troubleshoot problems.

LEFT:  ProSim737 User Interface (upper image) and Version Manager showing the release notes for a beta release.  The User Interface enables considerable customisation and includes features to customise updates, configure the simulator, check connectivity, and troubleshoot problems (click to enlarge).

The interface is straightforward to use and I urge you to become familiar with its tab /page layout and content.  I will discuss some of the troubleshooting features of the interface later in this article.

Included in the interface is a Version Manager that can be used to update the avionics suite.  When connected to the Internet, the Version Manager compares the release date of the currently installed avionics suite to the latest available release. 

The Version Manager enables the avionics suite to be updated from within ProSim737.  It's accessible from the User Interface (help/updates).

The Version Manager has three tabs:  Releases, Add-ons and Pre-releases.

Releases tab will display a list of final ProSim737 releases (along with release information and the date it was available).  To install the latest release, or to roll back to an earlier release, you select the install link in the Actions title.  This will cause the selected release to download and be installed to your computer overrighting (and updating) any previous release installed.

Add-ons tab displays various add-ons that ProSim-AR have made available.  An example being the ProSim737 aircraft flight model.

Pre-release tab will display a list of beta releases.  Operation is identical to the releases tab discussed above.

One of the advantages of the Version Manager is that it enables you to quickly update the avionics suite to a beta pre-release, final release, or roll backwards to an earlier release.  It also provides information concerning the beta release (Release Notes tab), in addition to enabling you to monitor respective updates to the 737-flight model (Add-ons tab).

Three methods can be used to update the ProSim737 avionics suite:

(i)     Download the latest release from the ProSim-AR website (standalone requiring installation);
(ii)    Download the latest release from the Version Manager (zip file); or
(iii)   Download and install from the Version Manager a beta pre-release or final release.

There is no preferred method, however, option (iii) is the easiest way.

Beta Pre-release or Final Release ?

ProSim-AR regularly adds functionality and improvements to their avionics suite via beta pre-releases.  A beta pre-release enables users to test their hardware set-up with a release prior to it being finalised.  As such, beta pre-releases often have bugs, shortfalls and other problems associated with them. 

ProSim-AR have a dedicated web-based forum, and request that beta users provide feedback on a pre-release.  This enables issues to be rectified prior to making available a final release via the Version Manager.

The Updating Process

The ProSim737 Version Manager (if used) is smart enough to replace all files within the ProSim737 folder system, with the exception of configuration files and any file ending in .xml (these files are kept intact). 

However, if a release is downloaded from the ProSim-AR website, or the ZIP file option is used, then it will be necessary to manually insert the configuration files to their respective folders.  

ProSim737 updates in sequence.  This means, that after the software has been downloaded, the main ProSim737 module will be installed and run  first.  Then as each .exe file for each additional module is run, that module will update. 

A pop-up box will display 'updating configuration' as each module updates its content and synchronises with the main ProSim737 folder.  When an update to a module has been completed, the software will generate the updatelog.txt file (as discussed earlier). 

The time taken to update across a network between server and client computers depends upon your network speed; usually less than 30 seconds.  

LEFT:  The User Interface showing the Database window.  In this window the Scenery Database can be checked and rebuilt.  The window also indicates what version of Navigraph is being used, and the status of the terrain data (click to enlarge).

Although theoretically not required, the Scenery Database (config/database) should be checked to ensure it's path is connected to the correct folder in Flight Simulator.  It also doesn't hurt to rebuild the database.  Rebuilding the Database following an update ensures that the link between the database, ProSim737 and Flight Simulator has not been corrupted.

Important Point:

  • Configuration files are generated in each folder as the .exe for each module is opened (run).

Customising How ProSim737 Updates

There are three ways that the User Interface can be set-up to update the avionics suite:

(i)     Manual updating;
(ii)    Ask before updating; and,
(iii)   Automatic updating.

The method is customised in the User Interface, accessible from the drop down box (config/configuration/updates).  The interface also has a box that an be checked/ticked if you want the interface to monitor when a beta release becomes available; a screen pop-up will be displayed when you open the avionics suite.

Backups and Install from Backup

I recommend keeping a complete copy of each ProSim737 folder from the server and client computer.  By backing up the complete folder, you are  also backing up the configuration and other important .xml files.

Theoretically, the Version Manager negates the necessity to maintain a backup of ProSim737 (or the configuration file), as the configuration and other .xml files are maintained intact.  However, by keeping a complete copy of the last ‘working’ release, it’s easy to ‘change out’ between releases (roll back or forward).  

All you need to do is delete the ProSim737 folders from the computer, and then copy/paste the earlier folders to the same locations.  All the files are intact and ProSim737 will load whatever release has been installed.

If you don't want to keep a complete copy of the folders and files, then it's also straightforward to roll back to an earlier release by using the Version Manager (this downloaded the selected release from the ProSim-AR server).

Important Points:

  • Always make a backup up your configuration (config.xml) files.
  • If downloading and installing a fresh copy of a release from the ProSim-AR website, then the configuration files will need to be manually added to each folder (from your backed up files).
  • Updates using the Version Manager replace all files within the ProSim737 folder system, with the exception of configuration files and any file ending in .xml.
  • The Version Manager displays the current release of ProSim737 you have installed.
  • A good idea to backup a copy of all the ProSim737 folders on both server and client computers.  Doing so allows you the option to easily replace a ProSim737 release with an earlier release number.
  • After running any update, the ProSim737 Scenery Database should be rebuilt.

Troubleshooting Updates

This section is not the ‘Holy Grail’ to resolve all problems.  Rather, it’s what should be done prior to requesting help from the ProSim-AR Development Group.  Some of the methods used to troubleshoot are quite simple, yet effective.

Occasionally there may be a problem with an update.  The update may cause one of the module’s .exe files to loop continually (open/close/open/close), or there may be limited functionality, or perhaps the ProSim737 main module will continually crash.

Recommended Initial Troubleshooting Protocols

Before spending valuable time in advanced troubleshooting, I suggest you check/do the following:

(i)     Shutdown all computers and restart;

(ii)    Ensure that all modules within all folders on the server and client computers have been updated to the new release (check the update file in the folder or check the release version number by right clicking the screen display and selecting configuration);

(iii)    Close and open all ProSim737 modules on the server and client computers;

(iv)   Check to ensure that the correct IP address is recorded for each display window opened.  To check this, right click the opened screen and select configuration.  This will open the screen’s user interface.  Check that the correct IP address recorded in the server box;

(v)    Check the version of .Net Framework on your client and server computer (discussed later);

(vii)  Replace the configuration file in the main ProSim737 folder with a copy of your backup configuration file;

(viii)  Delete all ProSim737 folders from your server and client computers and download/install from the ProSim-AR website a fresh copy of ProSim737 (remember to replace the configuration files in the ProSim737 folders to maintain your functionality settings and screen position); and,

(ix)     Open the User Interface and confirm that the correct simulator (ie: MSFS) is listed in the options box.  Also ensure the enable embedded MCP beta is not selected, all installed  I/O modules and software are operational, and the simulator is connected (config/configuration).  Furthermore, check that all appropriate drivers have been selected for the add-on components and software you are using (config/configuration/drivers).

Usually problems are resolved by restarting your computer, or reinstalling ProSim737 from a fresh download.  

On rare occasions, the configuration file in the main ProSim737 module may have become corrupted during the update process (jumbled and altered assignments).  If you suspect a problem with the config.xml file, and copy/paste your backup configuration file to the folder.

Often, the easiest and fastest method to alleviate issues and save considerable time is to DELETE all instances of ProSim737 from the server and client computers.  Before doing this make sure you have a backup of any files you may wish to keep (configuration files, etc.). 

Then, download the latest release of ProSim737 from the ProSim-AR website.  Copy the folders to the same location and add a copy of the respective configuration file to each folder.  Then, download the beta release (if required).

Advanced Troubleshooting, Log Files and Input Debugger

If the above-mentioned ideas have failed, or the problem relates to a switch, toggle or USB disconnection of hardware, then the next option is to use some of the features available in the User Interface.  Namely the: System tabs, Driver tab, Input Debugger, Logging features, and Debug Mode. (config/configuration/main tab/drivers tab).  Let's look at each in turn.

Main Tab 

After opening the User Interface, the first tab that is usually seen is the Main tab.  The Main tab displays a list of registered and connected interface cards.  It also displays the add-on software components that are specific to your simulator configuration.  This screen is ‘live’ meaning that as you add or remove a device or interface card from the computer the connection (and list) will be updated.

The main tab is particularly helpful in identiftying hardware USB disconnects (Windows USB disconnect ding-dong sound). 

In the case of USB disconnects, note any interface cards that you have connected that are either not displayed in the list, or flash on and off simultaneously with the ‘ding-dong’ sound; this will mostlikely be the offending card/device.  Often removing and replacing the USB connection will resolve a problem.

LEFT: User Interface showing content in Main tab.  This screen is 'live' and will update automatically when a device is plugged in or out of the computer.  The SimWorld MCP expansion + has been opened showing the various SimWorld components installed (click to enlarge).

If the problem is a connection or functionality problem that relates to an add-on component (for example SimWorld MCP, CP Flight, Flight Deck Solutions, etc.).

Click the + symbol adjacent to the name of the device in the software list. This will expand the selected folder for the item in question.  Components not operating correctly, or not connected will be highlighted in red.

Important Point:

  • The list displayed in the Main tab includes all legacy components (for example, interface cards that previously may have been used but are now not connected).  To reflect the most up-to-date items, the configuration file in main ProSim737 folder must be edited.  This post in the ProSim-AR forum explains how to remove these entries: Removing Old Entries in Config File.

Drivers Tab

One of the advantages in using ProSim-AR, is that the developer has pre-installed and checked the connectivity of drivers for several add-on hardware components.  This removes the need to regularly update drivers.

The Drivers tab displays a list of all drivers that can be used with ProSim737.  For an add-on component to function, the driver specific to that component must be selected (checked/ticked/turned on).  If it isn't then the component will fail. 

If you have updated ProSim737 to a newer release, and have not used the Version Manager (manual update from the website), then there is a possibility that the correct drivers for your components have not been selected.

Functionality - Checking Inputs and Outputs (System tabs and Input Debugger)

There are 2 ways that the User Interface can be used to check whether the movement of a component (input/output) is being registered by ProSim737 and operating correctly - System tabs and the Input Debugger.

System Tabs

The System tabs correlate to various aircraft and simulator systems, and when opened will display a list detailing the functionality of that particular system.

LEFT:  Aircraft System tabs with the Fire tab opened.  The display indicates that the triggered movement on the fire handles is functioning correctly (click to enlarge).

If the switch, toggle or whatever component in question is manipulated, there will be a corresponding indication shown in the Systems tab for that component.

I'm unsure if the System tabs were designed with problem troubleshooting in mind. Nevertheless, the various tabs can provide useful and helpful information and should form part of your troubleshooting system. 

Input Debugger

The Input Debugger (help/updates) is very easy to use, and the information it generates in its text box may help determine where a problem may reside.

The first time the Input Debugger is selected, a display window (debugger window) will open showing dozens of entries; the list can be confusing to read.  It's recommended to clear the list to make the debugger easier to use (press the clear list tab). 

LEFT:  Screen grab of Input Debugger. (click to enlarge).

With the Input Debugger open, you physically move the component in question (switch, toggle, lever, etc).  As soon as you move the component, you will note that its input, output and other related information is displayed in the debugger window.

The use of the Systems tab and Input Debugger is an ideal way to check that ProSim737 has registered the movement (input/output) of a component.

There is also a MCP debug option located in the config file of the MCP software.  Opening the debug option in the MCP only displays information concerning the MCP.

Log Files

ProSim737 generates two files that can be used for troubleshooting; the log.txt and crashlog.txt files. 

The main system log and crashlog files are located in the main ProSim737 folder, however, log and crash files are also located in any folder that a instance of ProSim is run from (for example, display folders, CDU and audio folder).  Scrutinizing these files can often provide incite to the cause of a problem.

The log files, with time can become quite voluminous.  This is because additional information is added to the log everytime  ProSim737 is opened.  Often it’s easier to view a file that displays information that relates to the last simulation session. 

Therefore, when trying to troubleshoot an issue, it's a good idea to delete the log.txt and crashlog.txt files. The software will automatically generate both files from scratch when ProSim737 is re-run, and the resultant entries will only be from the last simulator session - this makes for easier reading.

The detail of the log files can be increased if necessary.  To select more detailed (aka verbose) logging, open the User Interface (config/configuration).  In the Main tab, beneath Logging and Updates, there is a drop down box - select either normal or verbose logging. 

It’s recommended, when using the simulator, to leave logging set to normal (unless testing).  The reason for this is because the verbose option will generate a significant increase in the number of fentries to the various logs, and no doubt use system resources.  

If a crashlog file is not generated for some reason, navigate to the Windows Event Viewer.  The Event Viewer may provide further information (google Event Viewer if you are unsure what this is).

Important Points:

  • ProSim737 will generate a new log.txt and crashlog.txt file if either of the files are deleted. 
  • Whenever posting to the ProSim-AR forum a question concerning a problem, its a very good idea to attach the log.txt and crashlog.txt files to the thread.  These files can then be perused by the Development Group.

Debug Mode

The debug mode is an advanced option that should only be used when requested by the Development Group (config/configuration/main).   Some explanation of the mode is needed.

ProSim737 will only generate a crashlog.txt that relates to problems within its own software.  ProSim737 will not generate a crashlog.txt file is the problem is located outside of its software.  In such circumstances, the debug mode can be used to force ProSim737 to generate a crashlog.txt file.  This may aid in troubleshooting.

The debug mode will generate a large volume of entries, which to anyone but a software developer will be  nonsensical.  The generated files should be sent to the Development Group.

Important Points:

  • If the problem you are experiencing does NOT generating a crashlog.txt file (after deleting the file), then the problem is NOT related to the ProSim737 software, but rather to an outside source.
  • The debug mode should ONLY be used to generate the crashlog.txt file, after which it should be turned off.  Furthermore, it should only be used if requested by the Development Group.

Other Potential Causes of Problems

The list could be infinite!  However, the following 'potential culprits' seem to regularly cause problems for some users.

Opening Sequence of ProSim737 Modules and Flight Simulator

Sometimes following an update, ProSim737 will crash (drop-out).  If this should occur, there may be an issue with the sequence that the various programs are opened (run).

Theoretically, all the ProSim737 modules should connect automatically with the main ProSim737 module no matter what sequence they are opened. This said, changing the sequence that the ProSim737 main module is opened can resolve the issue.

Some users have reported that opening P3D/FSX before ProSim737 resolves drop-out issues, while others indicate the opposite.  Likewise, some users report that the main ProSim737 module should be opened prior to opening the other ProSim737 modules.

Whatever the correct sequence, changing the sequence that programs are opened should form part of your initial troubleshooting regime.

Windows Power Management Settings

If a USB device disconnect occurs after a period of elapsed time, then the computer’s Power Management Settings should be checked.

The Power Management Settings  enable the computer to turn off a device to save power; this is done following a period of elapsed time, or after a device has not been used for some time (for example, USB devices and display monitors).

LEFT:  Screen capture (Windows 10) showing Device Manager and Power Management Settings properties box (click to enlarge).

Earlier operating systems maintained the settings established in Power Management, however, Windows 10 has a nasty habit of changing the Power Management settings without warning.  Therefore, the first check should be the device manager to check that the settings are as they should be.  

In the Device Manager dialog box, expand the Universal Serial Bus controllers tab, right-click each USB Root Hub, and click Properties. In the USB Root Hub Properties dialog box, click the Power Management tab.  The setting that allows the computer to turn off the device must be turned OFF (do not tick/check).

Additionally, check the Power and Sleep options. Depending on the operating system used, there may also be other tabs associated with power options.  Search Advanced Power Settings/USB/ and suspend/disable power management or sleep functions.

.Net Framework

Without going into detail, .Net Framework (pronounced dot Net) is a language that is designed to bridge other computer languages so that they can be understood.  .Net Framework is designed and written by Micro$oft, and ProSim-AR have used it in newer releases of ProSim737.  

As at writing, the latest .Net Framework release is 4.72.  ProSim737 (release 214 and above) will not function without .Net Framework release 4.72 being installed.  .Net Framework must be installed to all client and server computers.

Windows 10 Updates

Windows 10 has a feature that automatically updates essential files (as determined by Micro$oft) when the computer is connected to the Internet.  Often, the user is unaware that the files have been updated, as the update occurs in the background.

Sometimes a problem will occur when a Windows update deselects features in ProSim737 that are necessary, such as drivers, etc.

The Windows 10 updating feature can be deactivated if you use Windows 10 Professional, however, it cannot be deactivated in the Home edition (without registry hacking). 

Batch Files and Shortcuts

It’s common for individuals to use a batch file to open ProSim737, or at the very least to use a shortcut to the original .exe file within a specific folder.  It’s also commonplace to rename the .exe file to something meaningful other than ProSim Display (of which there are several instances).  

DO NOT rename the original .exe file.  Rather make a shortcut to the file (right click and make shortcut) and rename this file.  If you do rename the original .exe file, the Version Manager will not replace the renamed .exe file and the release update will fail.

Dedicated Forum and Requesting Help

ProSim-AR has a dedicated forum that is actively monitored by the Development Group. 

If unable to resolve your issue, the log.txt and crashlog.txt files can be posted to the forum along with a detailed subject line and description of the problem.  In most cases, the Development Group rectify problems quickly.  Failing this, you can submit a support ticket via the ProSim-AR website.

Important Point:

  • I cannot emphasis the importance of a detailed subject line.  It's counter intruitve to think that someone will open a thread that says "Help Me" or "Problem PS Doesn't Work" as oppossed to "Marker Sound Not Working With PS Audio", or "MCP Disconnects when Opening ProSim".


The above mentioned information is valid as at the time of writing with Release Version 2.20b2.  However, ProSim-AR frequently update their software, and a future update may change what I have documented.

Final Call

The procedure to update the ProSim737 avionics suite is relatively straightforward, and the updating process streamlined and effective.   Nevertheless, the avionics suite is a complex piece of software and problems can occur following an update.  

The User Interface and Version Manager are powerful tools that can be used to customize the way that ProSim737 is updated and configured, and be used to troubleshoot problems.  Additionally, highly detailed logs can be generated which can be used by the Development Group to aid in rectifying problems.  This said, often the easiest solution to resolve a problem is to reinstall ProSim737 to its virgin state (from the ProSim-AR website), and reinstall your backed up configuration files.

This article has dealt primarily with updating and some of the potential problems that may develop; troubleshooting has only been briefly addressed.  Despite this, the above-mentioned recommendations should rectify most of the problems that may present when updating the avioincs suite.

Acronyms and Glossary

Development Group - ProSim737 Development Group (software developer).
Level D/Type 7 Simulation - Full flight simulator (FFS) is a term used by national (civil) aviation authorities (NAA) for a high technical level of flight simulator. ... A Level D/Type 7 simulator simulates all aircraft systems that are accessible from the flight deck and are critical to training.
Manipulate - A term to mean move.  It could be a switch, toggle, button, lever or anything else that can be physically moved.
Run - Term meaning to run or open a program.
User Interface - The User Interface used to access the customizable features of ProSim737.  The User Interface is accessible by clicking the ProSim737 icon.
Version Manager – ProSim737 user interface used to configure and customise the ProSim737 avionics suite.


Correcting Lag in ProSim737 Weather Radar

This short article relates only to the ProSim737 avionics suite.

The software that controls the avionics suite enables many features to be displayed on the Primary Flight Display (PFD) and Navigation Display (ND), and it's paramount that the PFD and ND display the best possible rendentation of the avionics that is possible.  Anything less will detract from the simulation experience.

ProSim-AR (the developers of ProSim737) are constantly updating their software to facilitate new features, functionality, and improve on existing functionality within the avionics suite.

One area of improvement recently implimented has been the detail that the terrain and weather (from the weather radar) is displayed on the ND.  

Performance Issue

Although the improvement is welcomed, many enthusiasts have reported performance issues when the terrain, or more specifically, the weather radar is displayed.  The condition usually becomes worse when other functionality, such as waypoints, airports, stations, and data are also selected on the EFIS to display on the ND (in addition to terrain and weather radar).  

The performance spike presents as a stuuter, lag, or pause, and this becomes more evident when the aircraft is climbing or banking; the altitude tape in the PFD stutters, as does the compass rose as it moves to a new course heading.

Attempting to Resolve Lag

ProSim-AR have attempted to resolve the issue of lagging, by releasing an alterative method to how the software interprets and displays the data (Direct2D).  Although the use of Direct2D has been ‘more or less’ resolved the display lag or stutter, other problems have surfaced such as the positioning and clarity of the displayed fonts.

It’s important to realize that the lagging issue is not a direct result from a low performance computer or graphics card.  Although using a high-end computer and graphics card will help to provide the necessary ‘grunt’ to display the data without any lagging.

Possible Solution to Lag

On my simulator set-up, I was using one computer monitor and one instance of ProSim737 (ProSim Display) to display the data on the PFD and ND.  Using this combination, my set-up always exhibited lagging and stuttering.  

Recently, I decided to run one instance of ProSim Display for the PFD and another for the ND, while displaying both the PFD and ND on the same computer monitor.  In other words, I seperated the resources that are used to display the PFD and ND.

I was surprised that this combination resolved the lagging problem.  I can now operate the ND with waypoints, airports, stations and data, and change between the weather and terrain display without any major lagging being evident on the altitude tape of the PFD or ND compass rose (assuming the aircraft is climbing and/or banking).


Setting up the two instances of ProSim Display to feed directly to one computer screen is straightforward.  However, configuring the position of the PFD and ND so that they are adjacent to each other and can be seen simultaneously can be ‘tricky’.  It does take a little bit of time to set up.

Prior to changing anything, always make a back-up copy of your config file.  This file, amongst other things, contains the last position of your various displays on the computer monitor.  The config file is located with the ProSim Display folder.

Excess Data Display

The ND will often display the words 'Excess Data'.  This message indicates that the ND is not capable of displaying all information.  If you deselct an ND option on the EFIS, the display will usually extinguish.  The display also appears on the the ND in the real aircraft.

The message can be disabled in the ProSim737 Instructor Station.

Final Call and Disclaimer

This simple proceedure resolved the issue of lagging on my simulator set-up, however your ‘mileage’ may differ.  Each computer is unique and the results I experienced may not be replicable on your set-up.

If it doesn’t work, then delete the config file and replace it with the backed-up copy.  This will revert the position of the displays to your earlier set-up.  

At the time of writing this article, I was using ProSim737 Version 219b10 with Lockheed Martin P3D Version 4.4 and 4.5.


Repair Backlighting on Throttle Quadrant 

During a recent flight, I noticed that the bulbs that illuminate the backlighting for the trim and flaps lightplate (First Officer side) had failed, however, the backlighting on the Captain-side trim lightplate was illuminated.  My first thought was that the 5 volt bulbs that are integrated into the lightplate had burned out; after all, everything has an end life.

LEFT:  The rear of the First Officer side trim lightplate showing one of the two terminals that the wiring loom connects to (click to enlarge).

Backlighting - Wiring Loom

The wiring loom that supplies the power for the backlighting enters the throttle quadrant via the front firewall, and initially connects with the trim lightplate and parking brake release light on the Captain-side.  A Y-junction bifurcates the wire loom from the Captain-side to the First Officer side of the quadrant, before it snakes its way along the inside edge of the quadrant firewall to connect with the First Officer side trim lightplate, and then the flaps lightplate.  The wiring loom is attached securely to the inside edge of the throttle casing by screwed cable clamps.

The backlighting for all lightplates is powered by 5 volts and the backlighting on the throttle quadrant is turned on/off/dimmed by the pedestal lighting dimmer knob located on the center pedestal. 

Finding the Problem

Ascertaining whether the bulbs are burned out is uncomplicated, however, assessing the terminals on the rear of each lightplate, and the wiring loom the connects to the lightplates, does involve dismantling part of the throttle quadrant.

The upper section of the throttle quadrant must be dismantled (trim wheels, upper and side panels, and the saw tooth flaps arc).  This enables the inside of throttle quadrant to be inspected more easily with the aid of a torch (lamp/flashlight).  When removing the trim wheels, be especially vigilant not to accidently pull the spline shaft from its mount, as doing so will cause several cogs to fall out of position causing the trim mechanism to be inoperable.

After the lightplates have been removed, but still connected to the wiring loom, a multimeter is used to read the voltage of each respective terminal on the lightplate. If the mutlimeter indicates there is power to the terminals, then the bulbs should illuminate. 

What surprised me when this was done, was that the bulbs worked perfectly. Therefore, it was clear the problem was not bulb, but wire related.

Process of Elimination

The process of elimination is the easiest method to solve problems that may develop in complicated systems.  By reducing the components to their simplest form, a solution can readily be attained.

If you suspect that the wiring is the problem, and don't have a multimeter, then a quick and fool safe method is to connect an alligator cable from the positive terminal of the Captain-side lightplate to the respective terminal on the First Officer lightplate.  Doing this removes that portion of the wiring harness from the circuit. 

LEFT:  Alligator wire connects power from Captain-side lightplate to the First Officer lightplate.  Note the frayed outer layer of the white aircraft wire.  The gold colour is a thin layer of gold that acts as a fire retardant should the wiring overheat (click to enlarge).

In this scenario, the  bulbs illminated on both trim lightplates.  As such, the problem was not bulb related, but was associated with the wiring loom.

It must be remembered that the wire used to connect the backlighting in the throttle quadrant is OEM wire.  As such, the age of the wire is the same age as the throttle quadrant.  

Inspecting the wire loom, I noticed that one of the wires that connected to the terminal of the lightplate was severed (cut in two).   I also noted that the original aircraft wires had begun to shed their protective insulation layer. 

Aircraft Wire and Insulation Layers

The high voltage and amperages that travel through aircraft wire can generate considerable heat.  This is why aircraft wire is made to very exacting standards and incorporates several layers of insulation that surround the stranded stainless steel wire.  The use of high-grade stainless steel also provides good strength and resistance to corrosion and oxidation at elevated temperatures.  

Interestingly, one of the insulating layers is comprised of gold (Au).  The gold acts as an effective fire retardant should the wires overheat.

LEFT:  The green wire has been severed.  A possible scenario was that the wiring loom had been pulled slightly loose from the throttle chassis, and had become caught in the flaps mechanism.  When the flaps lever is moved, the mechanism can easily crimp (and eventually sever) any wire in its path.  If you observe the white wire you can see the insulation that is shedding (click to enlarge).

The breakdown of the upper insulating layer is not a major cause for concern, as a 'shedding' wire still has enough insulation to not arc or short circuit.  However, the wire should be replaced if more than one layer is compromised, or the stainless threads of the wire are visible.

 Possible Scenario

When inspecting the wiring loom, I noted that one of the screws that holds the cable clamp to the inside of the throttle casing was loose.  This resulted in part of the wire loom to 'hang' near the flaps arc mechanism.    It is possible that during the throttle’s operational use, the movement and vibration of the aircraft had caused the screw to become loose resulting in the wires hanging down further than normal.  It appears that the wire had been severed, because it became caught in the mechanism of the flaps lever.  

Unlike reproduction throttles, the parts used in an OEM throttle are heavy duty and very solid; they are designed to withstand considerable abuse.  The speedbrake lever, when activated can easily cut a pencil in two, and the repeated movement of the flaps lever, when moved quickly between the teeth of the flaps arc, can easily crimp or flatten a wire.

Rather than try to solder the wires together (soldering stainless wire is difficult) and possibly have the same issue re-occur, I routed the wires from both lightplates (trim and flaps) directly to the 5 volt bus bar located in the center pedestal. 

I could have removed the wire loom completely and replaced it with another loom, however, this would involve having to disassemble the complete upper structure of the throttle quadrant to access the wire loom attachment points on the inside of the throttle casing; something I was not keen to do.

Final Call

OEM parts, although used in a static and simulated environment can have drawbacks.  Apart from age, the repeated movement of mechanical parts and the vibration of the spinning trim wheels, can loosen screws and nuts that otherwise should be securely tightened. 


OEM – Original Equipment Manufacturer
Wire Loom – Several wires bundled together and attached to a fixed point by some type of clamp


Using OEM Panels in the MIP

The introduction of the Boeing 737 Max has meant that many carriers are updating their fleets and retiring earlier production 737 NG airframes.  This has flow on benefits for flight simulator enthusiasts, because more and more OEM NG parts are becoming available due to NG airframes being stripped down and recycled.  

LEFT:  OEM Captain-side DU panel.  Note the thick engraving and specialist DZUS fasteners (click to enlarge).

Although some items, such as high-end avionics are priced outside the realm of the average individual, many other parts have become reasonably priced and are often a similar price to the equivalent reproduction part.

This article primarily relates to the panels used in the Main Instrument Panel (MIP), and lower kick stand.  The term panel means the aluminum plate that is secured to the framework of the MIP, and lightplate refers to the engraved plate that is secured to the panel.

Do You Notice The Difference

This is a common question.  The resounding answer is yes – the difference between OEM and reproduction parts can be noticed, especially if you compare the identical parts side by side.  This said, some high-end companies manufacturer panels that are almost indiscernible from the OEM panel.  These panels are bespoke, expensive, and usually are only made to a custom order.  Therefore, it really depends on which manufacturer/company you are comparing the OEM panel against.

By far the biggest difference between an OEM and reproduction panel, other than appearance, is the tactile feel of a knob, the overall robustness of the panel, and the firmness felt when rotating a commercial-grade switch; the later feels very accurate in its movement. 

LEFT:  Close up detail of OEM lightplate and general purpose knobs (click to enlarge)

There is litle compromise with backlighting as an OEM panel has a consistent colour temperature and intensity without hot and cold spots.  

Using a real panel helps to provide immersion and, as your're using a real aircraft part there is no second-guessing whether the panel is an accurate copy; using an OEM panel is literally 'as real as it gets'.  Furthermore, it’s  environmentally friendly to use second hand parts.  New parts (reproduction or otherwise) are made from  finite resources. 


Not every OEM part can work in a home simulator.  For example, the OEM potentiometer responsible for the dimming function in the lower kickstand DU panels cannot be used.  This is because Boeing use a rheostat instead of a potentiometer.  Without going into detail, a rheostat is designed to take into account 115 volts AC commonly used in aircraft.  If using these panels. you will need to change the rheostat to a high-end commercial potentiometer.  

Table 1 outlines 'some' of the main differences between the OEM panels and their reproduction equivalents.

Table 1:  Main differences between OEM and reproduction panels (MIP only).

The information presented in the above table, should not be taken in a way that reflects poorly on the manufacturer of reproduction panels.  There are a few high-end companies whose panels are indiscernible from the real item; it’s the purchaser’s knowledge and the manufacturer’s skill that will define whether a reproduction panel replicates the real item.   ‘Caveat Emptor’ should always be at the forefront of any purchase decision.

Potential Problems Using OEM Panels in the MIP

Potential problems often surface when attempting to mate OEM parts to the framework of the MIP.  This is because reproduction MIPs rarely echo the identical dimensions of their OEM counterpart. 

It's not possible to document every potential problem, as all reproduction MIPs are slightly different to each other.  However, some issues encountered may be the misalignment of screw holes between the MIP framework and the OEM panel, the inability to use the panel's DZUS fasteners, the panel being too large or too small for the MIP in question, and the open framework structure at the rear of the panel (which incorporates the wiring lume and Canon plugs) interfering with the infrastructure of the reproduction MIP, or the mounting of the computer screens.

In general, OEM panels cannot be mounted to a reproduction MIP without major work being done to the framework of the MIP.   The solution is to use a MIP that has been designed 1:1 with the OEM MIP, or fabricate a MIP in-house to the correct dimensions.

Specifics to the FDS MIP

The MIP used in the simulator is manufactured by Flight Deck Solutions (FDS), and although the MIP is made to a very high quality, the dimensions of the MIP are not 1:1. 

LEFT:  OEM Stand-by instrument panel. Although difficult to see from a picture, the overall robustness of this panel surpasses all but the very best reproductions (click to enlarge).

The most problematic issue is that the MIP length is slightly too narrow to enable the OEM panels to be fit correctly to the front of the framework.  For example, the OEM chronograph panel is 1 cm wider than the FDS chronograph panel.  Furthermore, most of the OEM panels (such as the standby instrument, chronograph and landing gear panel) measure 130 mm in height as opposed to the FDS panels that measure 125 mm in height.  This causes problems when trying to line up the bottom of each panel with the bottom of the display bezels

The standby instrument panel does fit, however, there is a few centimeters of space between the panel and the adjacent display bezel frame.  In the real aircraft, the display bezel and the edge of the standby instrument panel almost abut one another.  The autobrake panel does fit as do the lower kickstand panels.

FDS use screws to attach their panels to the upper MIP framework, however, OEM panels use DZUS fasteners.  The screw holes on the FDS MIP do not align with the position of the DZUS fasteners in the OEM panel.  The lower MIP panel (kickstand) in the real aircraft also incorporates a DZUS rail to which the panels are attached.  The FDS kickstand does not use a DZUS rail, and screws or reproduction DZUS fasteners are needed to secure the OEM kickstand panels.

The above said, FDS does not state that their MIP is I:1, and when asked will will inform you that OEM panels will not fit their products without considerable fabrication.

Specialist DZUS Fasteners

The OEM panels used in the upper MIP incorporate into the panel a specialist DZUS fastener.  This fastener is used to tightly secure the panel to the framework of the MIP; screws are not used.  Screws are only used to secure the lightplate to the panel. 

LEFT:  DZUS fastener that secures DU panel to the MIP framework (click to enlarge).

The DZUS fastener is shaped differently to the fasteners used to secure the panels located in the lower kickstand, overhead and center pedestal, and these parts are not interchangeable. 

Reproductions rarely replicate these DZUS fasteners.  However, like many things it's often the small things that make a difference (at least aesthetically).

LEFT:  Rear of OEM Captain-side DU panel.   Note heavy duty rotary switches (Cole & Jaycor brand), neat and sturdy wiring lume, and easy connect Canon plug.  The use of the correct bracket in the panel enables the AFDS unit to fit snugly to the panel.  Note the depth of the external frame which can cause placement issues (click to enlarge).

Advantages Using OEM Wiring Lume and Canon Plugs

A major plus using any OEM panel is that the part usually includes an expertly-made wiring lume that terminates at Canon plug.    If possible, the original wiring lume should be kept intact and additional wiring should be done from the Canon plug.  It’s very difficult to duplicate the same level of workmanship that Boeing has done in relation to the wiring.  Furthermore, the wire that has been used is high-end aviation grade wire.

The Canon plug deserves further mention, as the use of a Canon plug (or any connector for that matter) enables you to easily remove the panel for service work should this be required.  If at all possible, the original Canon plug (and wiring) should be used because it’s neat and tidy and ensures a good connection.  However, if the correct Canon plug cannot be procured then a reproduction plug should be fabricated.  There is nothing worse than having to disconnect wires from an interface card to remove a part.

Configuring an OEM Panel

Configuring an OEM panel to use in flight simulator depends on which panel you are referring to. 

LEFT:  OEM landing gear panel. Like any OEM part, the neatness in relation to the wiring is immaculate.  A Canon plug enables the panel to be connected to a lume which then connects with whatever interface card is in use (click to enlarge).

Panels with knobs, toggles and switches are relatively straightforward to interface with a respective interface card (Phidget card, PoKeys card, FDS SYS card or similar).  Determining the pinouts on the Canon plug that control backlighting requires the use of a multimeter, and then connection to a 5 volt power supply.  If the panel includes annunciators (korrys), then these will need to be connected to a 28 volt power supply (using the correct pinouts).

Technology is rarely static, and there are other ways to interface and configure OEM panels.  The ARINC 429 protocol is becomming inceasingly common to use along with specialist interface cards, and these will be discussed in separate articles.

The Future

The FDS MIP can, with some work, be modified to mount the OEM panels.  However, an easier option is to find another MIP that has been designed to mount the panels, or fabricate a MIP in-house to OEM dimensions.

LEFT:  Rear of DU panel showing korry connections and AFDS bracket (click to enlarge).

Final Call

Aesthetically, nothing beats the use of an OEM panel, and the panels used in the upper MIP and lower kickstand offer little comparison to their reproduction equivalents, with possible exception to bespoke reproductions. By far the biggest challenge is determining the pinouts for the Canon plug, but once known, configuration using a Phidget or other traditional card is relatively straightforward. 

As straightforward as it may seem, potential problems surface when attempting to mate OEM panels to an existing reproduction MIP.  To resolve these issues, often a replacement MIP is needed that has been made to the identical dimensions of the OEM counterpart.

Additional Information

The following articles may provide further information in relation to using OEM parts.

Note that some of these articles are to be reviewed and brought up-to-date (technology and ideas are rarely static).


ARINC 429 - Aircraft communication protocol
DU - Display Unit
Lume - A harness that holds several wires in a neat way
OEM - Original Equipment Manufacturer
MIP - Main Instrument Panel