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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).


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

Journal Archive (Newest First)

Entries in Avionics Panels (5)


Variation in Panel Colour, Manufacture & Location - Center Pedestal

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

(i)         The colour of the panel and lightplate;

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

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

(iv)       The manufacturer of the panel, and;

(v)        The aesthetic condition of the lightplate.

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

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

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

Colour of Lightplates

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

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

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

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

Position of Panels in the Center Pedestal

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

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

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

Panel Condition

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

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

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

To see additional photographs, navigate to the image portal.


SISMO Soluciones - Avionics Review: My Negative Experience 

 I initially wasn't going to document my negative experience with Sismo Soluciones as many simmers use SISMO products and are fiercely loyal to this company.  This post has sat unpublished for close to 10 months until a friend convinced me otherwise, saying that bad reviews can be beneficial, especially to new simmers who are undecided on what and whom to purchase from.

This is the first negative review I have written and in doing so realize that I will no doubt annoy some people, especially loyal SISMO customers.  My aim is not to annoy, intimidate or create malicious rumours.  Rather, it is to share with others my experience with this company. Due to the negative nature of this review, it WILL NOT be posted to any forum.

I purchased the following units from SISMO:

  • ADF radios (2)
  • Transponder / ATC radio
  • Audio Control Panel 
  • rudder trim module

At the time, I was using Sim Avionics as my avionics suite.

I had issues with: aesthetics, quality assurance and the SC Pascal script usage.  

When you initially look at the modules offered by SISMO, they do look attractive; however, it's often the small things that count and SISMO, in many respects, lacks quality and attention to detail.

  • This post is a little different.  I've made a basic review of the modules, then discussed the issues I had with the panels/modules and the company.

Overall Module Construction and Appearance

The modules are constructed from acrylic and painted in Boeing grey.  CNC machining produces a crisp finish resulting in lettering cut-outs that are well defined allowing back lighting to illuminate the lettering.  Buttons and switches are machine injection moulded and secured to rotary stems via two small grub screws. The electronics are not sealed within the unit (such as in CP Flight) but are visible.  DZUS fasteners are not included although holes have been drilled in the appropriate position (although these holes are too small to fit genuine DZUS fasteners).  The backing plate is made from plastic.

Paint Work

The paint work used by SISMO is not of a high quality.  The paint wears thin on the panel beneath the knobs and switches after minimal use.  The paint also chips very easily and is not evenly applied to include the side of the unit.  Although I don’t know how many layers of paint have been used, I’d suggest it’s minimal.  Minimal paint saves time and expense and does not lend itself to high quality and longevity.

Integrated Back-Lighting (IBL)

SISMO does not utilise real aircraft bulbs for backlighting.  Rather they use a number of strategically placed LED lights.

LEFT:  SISMO ADF unit & FDS NAV1 unit.  Note the difference in backlighting and module colour between the two units.  FDS use real aircraft bulbs. 

There are several arguments for and against the use of bulbs and LEDs.  The former provide a realistic throw of light at the correct colour temperature, while LED’s are usually more pin point, require less power to run and usually appear colder in colour temperature.

The Backlighting on the SISMO modules is reasonable; however there is not an even throw of light across the rear of the modules to allow complete illumination of all cut out lettering, nor does a light skirt inhibit stray light from illuminating the outer edge of the modules  The backlighting is powered by 12 volts.  The colour of the LEDS is amber yellow or warm orange.

I had an issue with two LED lights; The LED lights stopped working.  SISMO informed me I would have to repair this myself.  Shortly thereafter, a third LED light failed. This suggests that SISMO may have a quality issue in relation to LEDS (at least in the batch I received).


The upper panel of the module is attached to the electronic circuitry within the lower section by a backing plate.  This backing plate is made from plastic.  It should be constructed from metal to aid in strength.  The electronics “appears” substantial and to be well built.  

System and I/O Cards

The modules are not stand-alone devices.  Depending upon your requirements, the modules require connection to various system and sim cards for complete operation.  As an example, to operate the ADF units and rudder trim module requires three GIC connection cards, an Ethernet motherboard card, and three servo-daughter cards – seven cards in total!  

Although there is nothing wrong with this method of operation, it does pose a challenge to find a suitable location to mount the cards.  The cards appear to be constructed to a high standard and are very solid; they do not feel or look like cheap Chinese cards.

The main Ethernet mother board requires a 5 volt power supply.

I’ve included, for interest, a schematic wiring and card diagram of the module set-up for the Captain-side ADF radio. (click the image to enlarge the picture). 


SISMO provides you the opportunity to either use their prefabricated flat wiring or to wire everything yourself.  I choose the former and this saved a lot of time and frustration wiring and soldering.  The flat wiring packs are each fitted with heavy duty plastic clips for attachment to the cards.  Connection is straightforward and SISMO provide large A3 colour wiring sheets so you know exactly what wire plugs into what card.

When you do utilise the flat wiring, it’s necessary to include in your system a number of additional cards that act as joiners between the different system cards and modules. These cards are called Generic Interface Cards (GIC), and are little larger than a credit card in size. 

Too Many Cards

The amount of wiring and number of cards needed to use SISMO products is ridiculous!  With four modules connected, the interior of the center pedestal is a mass of wires leading to and from various interface cards.  There are far better and easier alternatives available from other manufactures.  

LEFT:  SISMO modules, power and flat cabling.  There is a lot of cabling and several required interface cards that are required.

The Power of Ethernet

SISMO’s product range utilises Ethernet technology rather than USB.  According to SISMO literature, USB was not designed to carry the volume of information necessary for flight simulation.  Although USB is practicable and does work very well, it can on occasion malfunction (drop out) or slow the operation of the intended device by creating a bottleneck for information flow.  Ethernet, on the other hand, has been designed at the onset to allow for high information flows ensuring fast and consistent transfer of information.

Another benefit of Ethernet is that it doesn’t matter if the computer that your modules are connected to is not a high-end machine, as the speed of Ethernet flow far outweighs the need for a high-end machine as a client PC. 

An Ethernet cable is required to link the main Ethernet mother board, either directly to the computer or to a switch if using two or more networked computers.

Although the theory is sound, speed wise I don’t believe there is a great difference between using Ethernet or USB for the transmitted information loads (at least for the center pedestal).

Real B737 Center Pedestal - Not Drop & Fly

An important point to note is that the ADF and ATC radios will not drop directly onto the DZUS rails fitted within a real B737 center pedestal. 

SISMO modules have been designed so that the electronic boards, mounted directly beneath the panel, are flush to the edge of the module.  What this means is that the unit cannot be placed directly onto a rail, as the electronics board abuts the edge of the rails. 

LEFT:  The two tabs overlap the DZUS rails.  You must cut the DZUS rails to allow the module to fit the pedestal.

To allow correct placement in a genuine center pedestal requires that the DZUS rails be cut in the appropriate position.

All the other SISMO modules, other than the ATC and ADF modules drop onto the rails without an issue.

Misleading Information

During my initial research, I asked SISMO if their modules fitted a genuine center pedestal.  Juan Ma stated they were compliant and did fir genuine DZUS fasteners; however, when they didn't fit the rails, Juan Ma claimed he had misunderstood my question due to his poor understanding of the English language!

To utilise genuine DZUS fasteners, you will need to enlarge the attachment holes in each of the modules to allow the fastener to fit the hole.  A word of caution here – SISMO use plastic backing boards which will crack easily if you are overzealous with a power drill. 

This is why I mentioned earlier that modules that incorporate metal plates in their construction are a better investment.

Communication and Support

Support for SISMO is either directly via e-mail or by their dedicated forum.  All e-mails are answered quickly (in English or Spanish).  

All my e-mail communication with JuanMa and Cristina has been on a very professional level.  They are courteous, exceptionally patient and very helpful; both strive to help you as much as they can.  

SISMO Modules - a closer inspection

ADF Radio Module

Initially, you’re impressed when you look at the ADF modules.  The seven segment displays, illuminated in either amber yellow or warm orange are easy to read, well lit and look similar to the displays you would see on a real aircraft. 

As you turn the rotary knobs to change the frequencies there is no catching as the knobs are turned and the push-to-activate buttons do not stick in the down position when depressed. 


One small issue I immediately noticed was that the tinted window plate which sits over the frequency display is not secured; as opposed to other manufacturer’s modules that incorporate the plate into the actual construction of the module.  If you invert the modules the cover plate will fall out of the recess.  I decided this wasn’t a problem as how often are simulators inverted, and securing the plate is an easy exercise; a small piece of double-side tape is all that is needed.

My problems began after roughly four hours of use.  The frequency push-to-activate button was temperamental and would not allow the stand-by and active frequency to be changed with one push; several pushes were required.   The problem is intermittent, but it suggests an issue with clicking mechanism or the button itself.

The next issue to develop was with the rotary knob; turning the knob caused the frequencies to jump digits.  As with the push-to-activate button, the problem was intermittent but, was rectified when you closed and reopened the SC Pascal script.  Perhaps the script needed tweaking.

Knobs and Switches - Poor Quality

I was disappointed with the switch knobs used by SISMO.  The two ADF-ANT switches are hand injected low quality “plastic” (?) and have several small injection holes within each of the knobs.   For the minor cost involved, it would have been nice to use high quality machine-injected knobs.  

Each of the ADF-ANT switches slides onto and over the plastic circular shaft of the rotary mechanism.  The knob is then secured to the shaft by two grub screws each side of the knob.  It doesn’t take too long for the grub screws to become loose resulting in the knob slipping. 

Other companies have solved this potential problem by using D-shaped shafts or higher quality rotary switches incorporating metal shafts instead of plastic.

My rating 4/10

Audio Control Panel (ACP)

The Audio Control Panel (ACP) replicates the audio system of the B737 (navigation radios, etc).  The ACP occupies a large piece of real estate in the center pedestal and the ability to turn on and off navigation audio sounds should not be dismissed.

LEFT:  SISMO ACP unit does not look realistic with inexpensive poorly moulded buttons and very stark backlighting.  Note that some of the rectangular buttons are not in alignment.  This unit has been constructed with very poor attention to detail.  Note black knob is not a SISMO knob.

The main ACP switch is of similar construction to the ADF-ANT switches on the ADF module; it is poor quality with injection holes readily observed.  The clear push buttons used to turn on and off the various audio sounds are of low quality.  The buttons are fashioned from clear acrylic and lack detail and definition.  

I was disappointed that when the ACP unit was fitted onto the pedestal, light from the rear LEDS seeped through along the edge of the module (to stop this I applied masking tape to the side of the panel to create a light skirt.  I have also noted that some of the buttons are not accurately aligned with one another. 

Often it’s the small things that count and push a product to the next level. 

I was not impressed with the quality and attention to detail on the SISMO ACP unit; therefore, have decided to convert two real B737-500 ACPS to simulator use.

My rating 2-10

Rudder Trim Module

The rudder module incorporates a large knob that is center-spring loaded.  The knob allows the rudder to be deflected in either direction and be recorded in degrees of offset on the scale.  The movement of the defection needle is made possible with the use of small servo motor fitted beneath the module and powered by 12 volts.

The rudder trim knob is poorly moulded and shows hollow holes left over from the injection process.  For those searching for aesthetics, replacement using a real B737 knob is very easy (if you can find a real knob).

LEFT:  SISMO rudder trim module.  Note the very poor moulding on the knob and colour shift with lighting.

The trim needle, at least on my module, is a little lop-sided.  As with the ACP module, stray light from the LED back lighting is readily seen around the edge of the module.  Like other SISMO modules, there is no inclusion of a light skirt to stop straying light.

The remainder of the module is aesthetically pleasing.

The rudder trim is one of the modules that is necessary to complete a center pedestal, but unless one is regularly flying with one engine, the module is seldom used.  Therefore; this module from SISMO, even with the irregularities, is a reasonably priced alterative to some of the more expensive counterparts available.

My rating 5/6-10

ATC (Transponder) Module

This is one of the better produced modules from SISMO. 

The switches and knobs are well presented, there are no injection holes in the knobs, and the operation is very smooth when altering frequencies. The digital read out is crisp, yellow amber in colour, and the tinted window, which falls out easily on the ADF modules seems to be more secure (although it is the same drop in type).   As with the ADF modules, this module will require you to cut the DZUS rails if you are using a genuine 737 center pedestal.

As a script was never supplied with this module (SISMO did not send it), I cannot provide information to how well it operated.  

My rating based solely on appearance is 8-10

Reliability and Performance - Software and Modules

Software - SC Pascal Scripts

The modules require SC-Pascal scripts to be installed on the computer of your choice. 

The basic script is downloaded from the SISMO website.  A further “customised” script is needed to configure the modules to the avionics software package you are using (Sim Avionics, Project magenta, ProSim737, Orion, etc) and FSX.  SISMO generate this script for you and all you need to do is run the executable file when you open a flight session.

SC-Pascal scripts are completely new to me, but a little research indicates that the script is used as a software interface between the actual functionality of the avionics modules and FSUPIC / FSX.

Once the scripts are installed and configured correctly, a folder is created in which is stored the config.ini file and the executable script.  The folder and files can be named and stored anywhere on your computer system.   Activation of the modules is achieved by activating the executable script.  

Optionally, direct access to the script can be made by adding the executable command to the auto start folder of your computer.  This option automatically starts the modules when the computer is turned on.  The script then runs in stand-by mode until FSX is activated.  This saves time and repetition having to turn on the SISMO modules separately.

As SISMO utilises Ethernet technology, the various IP addresses of the computer (s) you are using need to be correctly configured to allow communication between the computer and the modules.  This is basic networking knowledge and is relatively easy to learn.

Once the software is configured, the software and modules should operate flawlessly.  

Script Problems

I did have some issues with the SC Pascal script freezing when it was initiated.  The script also caused some issues which appeared to cause the ADF radios to incorrectly display frequencies.  To Juan Ma's credit, he did tweak the script, however, the problems remained.

As I know nothing about SC Pascal scripts, I do not know with certainty whether the problems experienced were caused by a script issue, hardware issue, or something particular to my system.  I believe the issue may have been the SC Pascal script.

For those who know me, I try to keep things simple, and running multiple scripts for this and that does not exactly fit into this "ethos".  There already is the proven and tested FSUPIC, WIDEFS and configuring functionality through ProSim737.  Why complicate matters..... (I have learnt this lesson from experience...)

It would be inaccurate to state that SC Pascal scripts don't work, because there are many simmers who have them operating perfectly.  But, I am not one of these individuals.

Note that at this time using Sim Avionics and NOT ProSim737 avionics suite.

Quick List - Pros and Cons


  • Fairly accurate 1:1 ratio (or close to)
  • Easy to install and use software (knowledge of SC Pascal required if altering software)
  • Laser cut and stencilled lettering
  • Ethernet technology


  • Plastic shafts on ADF-ANT knobs (should be metal/stainless)
  • Poor quality knobs and switches on ADF, ACP and Rudder Trim module
  • Average light coverage for LED back lighting
  • ADF and ATC modules do not drop directly onto DZUS rails
  • Large number of cards needed for operation
  • Not DZUS complaint (requires existing holes to be enlarged)
  • Plastic backing plate (easily damaged when enlarging holes for DZUS fasteners)
  • Light seepage around edge of some modules from back-lighting (no light skirt)
  • SC Pascal script troublesome and works intermittently.
  • Poor quality paint work
  • Considering the above, expensive

Overall Opinion

The modules are ideal for the budget-conscious flight simmer.  

The lack of quality knobs, switches and poor attention to detail detract aesthetically, while the large number of cards that need to be installed can make installation challenging.  Three failing LEDS and problems with the frequency selector switch on the ADF radio unit may point to quality assurance issues.  The use of Ethernet over USB is highly commended and may reduce information bottlenecks.

My rating for the software is 4/10 (The supplied scripts did not work with my system, which at that time was Sim Avionics and not ProSim737).

My overall rating for the modules is 3/4/5-10 (based on fitting issues, quality of knobs, poor attention to detail, poor painting, no light skirts and temperamental frequency selection switches on ADF).

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



I have returned all the modules, cards and wiring  to SISMO for refund

Initially, SISMO offered me 10% of the value of the products purchased (this included I/O cards that had never been used).  

SISMO stated that the return period had been exceeded, and any products returned would be treated as second hand units.  It didn’t matter that SISMO had not, at that time, sent all the appropriate SC Pascal scripts to ensure correct operation of the modules.  

The writing of the SC Pascal scripts was delayed close on 2 months after I received the modules, and when received, the scripts did not operate as intended.  Excuses were; staff holidays, workloads, Easter break, and awaiting confirmation from another company to facilitate operation.  

Upon receipt of the returned items, SISMO claimed that many of my issues were incorrect or not relevant.

  • They claimed that the modules had been damaged.
  • They stated that I had broken the LEDS (I told them the LEDS were not working when I received the parcel).
  • They claimed I had disassembled the units and damaged the paint and screws.
  • They claimed I had re-painted portions of the units.
  • They claimed sticky plaster was attached to one of the units. (true as I used tape to secure the wiring together when I returned the units & also to create a trial light skirt)
  • They deducted from my refund, import duty and inspection fees, when I returned the goods to Spain.
  • They claimed I did not include paperwork (which I did). 
  • They stated that as the ATC RADIO module was discontinued, a refund was not possible.

I am not going to go into a long account to what has transgressed.  But, I will say that this company cannot be trusted…..They promise the world to you, but if you are not happy with the products, they provide every excuse possible to NOT provide an adequate and reasonable refund.

For example, when I reported the failure of the LEDS to SISMO, their response was “they worked when they left here”.  They did offer to replace the LEDS but, at my shipping expense.  They did offer a discount on further purchases due to the inconvenience.

It should also be noted, that in my initial correspondence with SISMO, I asked whether their modules would drop directly into a real B737 center pedestal.  Juan Ma stated “YES”.  However, on receipt it was discovered that the modules were too large to fit directly onto the pedestal DZUS rails.  I queried Juan Ma from SISMO on this; he stated that it was a language misunderstanding.

Juan Ma understood perfect English when it came to avoiding refunding my purchase money.

Legislation, PayPal and Delays

Spanish legislation states that every purchase has a 7 day cooling off period, in which a return and refund can be made.  PayPal policy states you have 45 days in which to make a claim.  EU legislation states that refunds are possible if items do not function correctly - within set time frame.

Without a working script for Sim Avionics (which took two months to receive), how can testing of modules occur!  Because of the approximate two month delay on sending operating scripts to me, all these options had expired.

I cannot help but think that SISMO delayed the sending of the scripts so as to provide a reason for NOT refunding 100% of the purchase price.

SISMO Solicones appears to be a company that will ONLY support and stand by their products if you want to purchase something or want to use it. 

If you ask for a refund on faulty components, components that do not work with your choosen avionics software suite, or scripts that do not function correctly, then expect NOTHING, or at the very least, a minimal refund (and you will have to fight to get this refund). 

What you can expect from SISMO, is e-mail after e-mail informing you that you have no right to refund, that you have damaged the items, that you did not follow SISMO policies, etc, etc.

After many e-mails I succeeded in gaining a E400 Euro refund for an initial E1400 Euro outlay.

I am sure there are many happy customers using SISMO product; however, I am not one and I do not recommend SISMO Solicones.  The quality of their products is poorly executed, attention to detail low, and attempt to maintain good customer relations non-existent (I was returning items)...

In my opinion, it is VITAL that a company standby and support their product-line, and this includes refunds if the product (for whatever reason) does not operate with your simulator set-up.

If you search the Internet, you will find very few comments regarding SISMO, other than company endorsed reviews on forums that are supported by manufacturers and resellers.

If you are searching for quality avionics modules, look no further than Flight Deck Solutions or CP Flight

These two companies are reliable, produce good products and provide exceptional after sales service.  They also offer a refund if not 100% satisfied with their product.  Whatever you do, don’t spend your money on inferior products from SISMO! (my opinion only).

  • This review is rather negative towards SISMO Soluciones; however,  I have "toned down” my anger to this company to produce a balanced and accurate review.  Please understand that this is my experience with this company.  Your experience may well be positive. 

The avionics panels/modules I am currently using are genuine Boeing items converted to FS use and modules made by Flight Deck Solutions and CP Flight.

Feel welcome to make comments, either good or bad in the comments section.


B737 Blanking Plates - Cover That Unsightly Gap

No matter what style of simulator you are using or have constructed, you will most likely have a center pedestal installed.  The pedestal will be either a two-bay or three-bay type and be a genuine aviation part incorporating DZUS fastener rails, or a reproduction unit manufactured from wood, metal or plastic.

LEFT:  An assortment of Boeing blanking plates complete with DZUS fasteners recently removed from a scrapped B737 - the dirt and dust is still on them!  Note three differing sizes - 1" 2" and 4"  (click image for larger view)

The two-bay pedestals, once allotted the standard Boeing avionics suite, usually have no  space remaining for additional avionics; however, the three-bay pedestals have substantially more 'real estate' and often gaps are remaining that are not filled with avionics.  Most enthusiasts either leave this space open which looks very unsightly, or manufacture their own plate to cover the gap.

OEM Blanking Plates

Why not use the real part….  

Boeing produces several blanking plates in varying sizes to be used to cover any 'gaps' not used in the center pedestal, forward and aft overhead panel, or Main Instrument Panel (MIP).  These plates are machine-grade light weight steel (or aluminum), are painted Boeing grey, and incorporate the required number of DZUS fasteners for attachment to DZUS rails.  The plates come in a variety of sizes with 1 inch, 2 inch, and 4 inch being the norm.

These plates are inexpensive and usually retail between $5.00 - $20.00 USD, and not only fulfill the task of covering an unsightly gap, but are easy to install, come precut, are painted the right colour, and usually have DZUS fasteners attached to them. 

If not using real DZUS rails and your pedestal in made from wood or plastic, then it’s relatively easy to remove the fasteners and replace them with reproduction screw-type DZUS available from GLB Products.

Most aircraft wrecking yards carry these plates, as airlines regularly purchase them.  Failing this E-Bay often has blanking plates for sale. 


NAV 1/2 & M-Comm Radios by Flight Deck Solutions - Review

This short review is for the NAV 1/2 Radio modules and M-COMM communication module produced by Flight Deck Solutions. 

As both modules are similar in construction, I will discuss them together.

The NAV module is a stand-alone USB driven Radio Management Panel. This single channel radio unit is designed to handle NAV frequency selection and management.

The M-COMM, a Multi-Channel Communications Radio is a highly detailed replica of the late model communications radio that incorporates COM 1 and COM 2 within the same module, thereby giving greater application to the crew.  For simulation purposes the M-COM is an advantage for those who only wish to purchase one module rather two seperate COM1 and COM 2 modules.

Construction and Appearance

The modules are constructed using the same technique that FDS construct their Main Instrument Panel.  Each upper panel is made from CNC machined acrylic which produces a very crisp finish and allows any lettering cut-outs to be very well defined.  The modules incorporate dual concentric rotary encoders with stainless stems.

High Quality

The knobs and switches, which are custom machine injected, are true to life and are tactile in feel.  As you click through the frequencies the movement is stable and well defined.  There is no catching as the knobs are turned.  The push keys on the units are plastic molded, back-lit and work flawlessly; they do not stick in the down position when depressed, and click back into position when pressure is released.  The frequency displays are 7 segment digits and are very easy to read.  Digit colours are in amber yellow for the NAV units and warm white for the M-COMM unit. 

The upper panel of the module is attached to the electronic circuitry within the lower section by a metal backing plate; this increases the strength of the unit and assists in the dissipation of heat.  An electronics friend had a look at the modules are seemed impressed with quality of the electronics board.  What this amounts to is a well presented piece of avionics that accurately replicates a real B737 module 1:1 in size.

No Interface Card Needed

The modules do not require control boards or interface cards - they are stand-alone USB devices.  The decision to incorporate all functionality within the modules minimizes the wiring required and the problem in finding space to attach a system board.  This is a very important point that needs to be reemphasized, as finding places for various system and I/O cards can be very challenging within the confines of a flight deck.  FDS’s decision to incorporate most of the electronic components into the actual module, by layering boards within and under the module, is to be commended and seen as a positive step forward in flight deck building.


ABOVE: You can observe the very cleanly constructed dual layer (triple?) electronics board and push clip which connects 5 Volt power for IBL.  Note that the electronics board is not flush to the edge of the module; thereby, allowing the module to drop easily onto DZUS rails (drop & fly).  Also note the inclusion of genuine DZUS fasteners.

Boeing Grey

All FDS B737 series modules and panels are professionally painted in Boeing grey.  Rather than one coat of paint which can easily be chipped, FDS utilises several thin coats to increase the durability of the unit’s finish.  Although this last comment may appear token, the quality of paint is important.  The modules will be used for many years and during the course of operation, you will be placing pens, clipboards, charts, coffee cups, etc on the center pedestal and the modules.  Further, as the units are flat, dust will accumulate requiring dusting and cleaning.  Low quality paint will scratch, fade and wear thin with time.

DZUS Compliant

If you are utilising real aircraft parts in your simulator, in particular a center pedestal, then any module that is DZUS compliant is advantageous as it allows for the module to be dropped directly onto the DZUS rails and secured by the DZUS fasteners.  All modules produced by Flight Deck Solutions can be secured using DZUS fasteners.

Integrated Back-Lighting (IBL)

IBL (proprietary design) is supplied with all FDS modules.  Real aircraft bulbs are used to illuminate the panels and modules.  One of the main advantages of IBL is the “throw of light” produced from a bulb in contrast to that of a LED.  The area of coverage from bulbs is relatively even; where as the light spread from an LED is minimal– almost pinpoint.  This is because LEDS are a very precise light source.  The only way to achieve a similar light coverage to bulbs is to use several LEDS mounted in close proximity to each other.  One area where the use of bulbs verses LEDS is obvious is the back-lit lettering; bulbs allow all the lettering to be evenly lit.

Other manufacturers of avionics modules use LED lights which do not replicate the same colour temperature or appearance of real aircraft lighting. 

The IBL is superb.  The only downside of IBL (if there is one), and this really doesn’t deserve mention, is that the bulbs generate quite a bit of heat.  The life of a bulb is also less than a LED. FDS claim their bulbs have a life span identical to that of real aircraft bulbs which is ~40,000 hours.

To view a good video of how FDS install IBL into the modules, check out the FDS IBL video here.

Set-up of Modules & Software

The modules require software which can be downloaded from the FDS website.

The software is very easy to use and installation self explanatory.  Configuration of the modules is done via the software and involves indicating which NAV module is operated by which pilot (Captain or first Officer).  The M-COMM module uses the same software and you check the option for this module during set-up.

LEFT: FDS IBL Panel Power Distribution Unit - the size of a credit card.  red wire connects to 12 Volts and coloured wires connect to 5 volts for IBL.

Once installed, a sub menu will be created in the FSX menu visible on the main screen.  This sub menu identifies the FDS modules you are using, facilitates module set-up (which radio handles what frequency) and allows a method to restart the module should a failure occur with the Tekworx software during flight.

Connection to the computer is via USB.  Back-lighting requires a 5 Volt power source and installation of a FDS IBL Panel Power Distribution Unit (FDS IBL DIST).  This small card is needed to share the power between the various modules.  It’s all pretty straightforward and involves connecting some prefabricated wires with clips to the rear of each module and to the card.  The card is then connected directly to the 5 Volt power supply.  I secured the card I have within the innards of the center pedestal.

Reliability and Performance – Software and Modules

Software - Instability Causing Module Disconnection (Drop-Outs)

The software that FDS uses (Tekworx) to operate the modules, for the most part, operates well. 

However, I do have issues with the software maintaining contact with the modules via USB.  For some reason, the software will drop out and the modules require re-starting.  I worked with Steve Cos in an attempt to solve this issue, and despite not discovering the reason for the drop outs, a new release of the software (V 1.9.9) appears to have partially rectified the issue. The issue still does occur, but not as frequently.

If the radios do drop out, it’s easy (but annoying) to re-open them by "mousing" over the FSX menu and selecting the FDS radio and multi-radio sub menus.  This will re-start the radio software.

Steve Cos has worked tirelessly with me over a period of 12 months to solve this issue, however, a solution to the drop outs and disconnection of the software has not yet been found.  I doubt that the problem is being caused my particular computer set-up and specifications, as I've installed the modules on another computer running different specifications and the same issue occurs.  It maybe a Sim Connect issue or a an issue with Tekworx software (?)

If the problem is not rectified by the time the simulator is completed, I will replace the FDS modules and move to another vendor to supply the various radios for the center pedestal.  Instability (no matter what the cause) is an annoyance and becomes intolerable after a considerable period.  It's a pity that the software that FDS uses to control the modules "appears" to be unstable (at least with my system) as their product range is beyond reproach when it comes to quality.


I've used modules in the past that when altering the frequency there is a very slight time lag for the frequency digits to catch up with the turning rotary. This time lag may well be system dependent and/or a response to the limitations of USB.  This delay is not evident with the FDS modules.

As mentioned earlier, the frequency digits are super sharp, well lit, and the knobs and switches very well made and tactile.

Comparing the modules I've used over several years (open cockpits, CP Flight, SISMO Solicones and Go Flight), those produced by FDS are probably the best on the market - second to the real thing.


Support from FDS is either directly via e-mail or by a dedicated forum.  The support provided by FDS is outstanding and all e-mails are answered in a timely manner.

Quick List – Pros & Cons


  • Well designed & constructed
  • Excellent workmanship
  • Superior product in many ways
  • Realistic Integrated Back-Lighting (IBL)
  • Realistic quality machine-injected switches & rotaries
  • 1:1 to the real B737 series aircraft
  • Very high attention to detail
  • DZUS compliant (drop & fly)
  • Easy to use and set-up software
  • M-COMM radio ideal if space is limited in pedestal


  • Expensive price (subjective)
  • Tekworx software (V 1.8.8. & V 1.9.9) causing module disconnection (drop-outs)

Overall Opinion

I am very impressed with these modules.  They are solid, well constructed and the attention to detail is as you would expect from Flight Deck Solutions.  The quality of the modules is very high and suits the high end enthusiast to professional market.  I's a pity that the software FDS use lowers their reliability (at least on my system)

My rating for the software is 5/10  (V1.8.8. & V 1.9.9)

My rating for the modules is 10/10

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


Populating the B737 Center Pedestal

The centre pedestal I’m using is a real aviation part procured from a South West B737-300 series aircraft. The pedestal came attached to the throttle quadrant and is the more uncommon two-column style for this series aircraft, rather than the three-column NG style.

I was reluctant to destroy a piece of aviation memorabilia, so rather than cut the pedestal from the throttle and discard it, I decided to keep the two-column pedestal and limit myself only to essential avionic modules.

LEFT: A mix-match in colour and manufacturers.  The center pedestal is a real aviation part as is the throttle unit.  The fire suppression panel came from a scrapped B737-500 whilst the F/O Audio Control Panel (ACP) came from 500 series aircraft.  The other modules are: FDS NAV & M-COMM and a  ATC transducer module made by CP Flight in Italy.  For those unfamiliar with a real pedestal, the flat pieces if metal with the light green paint on the upper side, fold down and are aluminium coffee cup holders !

Apart from the nostalgia of using a real bay, I really like the DZUS rails that are incorporated in a real bay which allow you to drop the various modules into place.  To read about DZUS fasteners, navigate to my earlier post.

No International Standard  - Variation

There is no international standard established to indicate which model/type avionics are installed in a center pedestal; more often than not, it will come down to the type of aircraft and a particular airline’s requirements.  Early series B737s were fitted with a twin column pedestal which minimised the number of modules that can be fitted.  Later model B737 aircraft and the NG series incorporate a three column pedestal to allow installation of the latest navigation and communication equipment.  There are benefits to the thinner two column pedestals, the main positive being more room to climb into the flight deck.

All B737s will have as a minimum the following avionics installed:  Fire Suppression module, NAV1/2 COMS 1/2, ADF 1/2, audio, rudder trim and transponder.  The important modules will be duplicated for First Officer use and redundancy should a failure occur.  Depending upon the aircraft series, the following may also be installed: thermal printer, HUD set-up, radar, cargo door panel & floodlight switches, alternate communications, etc, etc (the list is almost endless).  Much of what is installed depends on the use of the aircraft, civil regulations in the country of use and the requirement of the particular airlines.

Module Location

As with colour, there is no standardization to the location within the pedestal for any particular module - perhaps with the exception of the fire suppression module and NAV 1/2 module which (usually) occupy the forward part of the center pedestal.  Modules are fitted wherever they fit and in line with whatever specification that the airlines requires.  For example, I've observed Audio Control Panels (ACP) mounted toward the rear of the pedestal, which I believe is the favoured position, and also towards to front of the pedestal.

LEFT:  Note the ACP units are located further forward than what is considered the norm.  Also note the rudder trim module mounted in the centre of the pedestal and the rather larger thermal printer (?) toward the lower right. 

Another interesting aspect to observe is the different knobs on the NAV and ADF radios.  Often simmers became "mentally entangled" in attempting to standardize everything across their simulator.  This is not necessary and actually is more realistic if you mix-match slightly.

This pedestal is mounted within a B737-700 aircraft and represents the more usually found three column pedestal in this series aircraft.  The pedestal I am using came from an earlier 400 series aircraft and is the two column type.

I’ve populated the center pedestal with the following modules:

  • NAV-1 (Flight Deck Solutions)
  • NAV-2 (Flight Deck Solutions)
  • M-COMM (Flight Deck Solutions) new style module that incorporates all radios in one module
  • ADF-1 (CP Flight)
  • ADF-2 (CP Flight)
  • Rudder Trim (CP Flight)
  • ATC (transponder) (CP Flight)
  • Fire Suppression Module (genuine B737 unit converted for FS use)
  • Audio Control Panel (2) (ACP) (genuine B737-500 unit – only wired for lights at the moment)

Maintaining Brands – almost impossible

I had wanted to maintain the same brand of modules across the sim to minimise the number of different system cards and interfaces, however, this was difficult to do. 

Flight Deck Solutions, a premium upper shelf supplier of simulation parts to the professional and enthusiast market, do not currently produce an ADF radio module.   Further, FDS do not produce an older style ATC (transponder) module; they only manufacture the newer push button type and I favoured the older style.

CP Flight produces some excellent modules with a very easy to use daisy chain system for linking the modules together; it would have to be the easiest and less hassle-free system on the market.  As I already had the older style CP Flight transducer module left over from my older simulator, and am using the CP Flight MCP (which is required for daisy chaining if you do not use thier "black box"), I decided to incorporate this module.

I would have also used the ADF radios made by CP Flight, however, at the time of writing these modules are unavailable and there is no date determined to when they will be available.

Real Modules

Nothing beats real modules aesthetically...  I am hoping that as the project develops to replace some of the reproduction modules with real B737 modules converted to flight simulation use.  Currently, I only have the fire suppression module and Audio Control Panel (ACP) converted.  More research is required to learn how to convert other modules.  Perhaps real ADF modules :)   An ongoing project!

SISMO Solicones

Therefore, a relative newcomer to the scene attracted my attention – a Spanish company called SISMO Solicones.  Their products are reasonable quality for the price paid, are 1:1 ratio to real Boeing modules, use Ethernet rather than USB, and relatively easy to configure. 

I was very keen to trial Ethernet as a method to connect modules to the computer.  In a future post, I will review the actual modules and the benefits of Ethernet instead of USB.

Avionics Mania

Unless you have an unlimited budget, or have “module sickness” necessitating every module possible, you may want to think about how often you will use a particular module.  Navigation (NAV 1/2 & ADF 1/2) and communication (COM1/2) modules will be used on every flight; therefore, it’s best to purchase a high end module for consistency and reliability. 

The rudder trim module and Audio Control Panel (ACP) are rarely used, with the exception of engine out operations and for turning on/off the audio for the various navigational aids.  The later can be particularly annoying when tracking an active ADF.

This is a side benefit to using a two column pedestal:  there is less room so you can only select those modules with provide required functionality.  The extra space also helps when climbing into the flight deck  :)

Module Size – Size Matters!

It’s very important to check whether the module will fit correctly to whatever pedestal you are using.  If you’re building your own pedestal without rails, then this isn’t much to worry as you can easily fashion a template to drop the modules into.  However, if you’re using a real Boeing part, you will need to ensure that the modules are built in such a way that they drop into the existing rail system in the pedestal, otherwise you may need to alter your rails.

LEFT:  Note the electronics tab that needs to clear the DZUS rails for installation.  A poor module design if using a real pedestal.  If I had know this before purchase, I'd have selected ADF radios from another supplier.

ADF Radio Modules – Attaching to the DZUS Rails

The avionics modules made by Flight Deck Solutions are literally “drop & forget” as these modules are DZUS compliant and fit the DZUS rails perfectly.  The ADF radios from SISMO are a different matter.  Each of the modules has a small tab on the electronics board which was too wide to navigate past the DZUS rail to slide into the bay.  This was a major issue as the module cannot be dropped onto the rails.  Why SISMO designed them this way is beyond me, as many serious simmers use real aircraft center pedestals.

Cutting the Rail – Delicate Operation

Although I was reluctant to cut the DZUS rail, I realized that this was the only method available to correctly fit the SISMO ADF modules.  The rail had to be cut and a portion removed that corresponded to the size of the tab. Removing a portion of the rail would allow the module to then be dropped into the pedestal. 

The DZUS rails are attached at regular intervals to the inner side of the pedestal by several aluminium rivets.  The rivets are not moveable and unfortunately a rivet was located directly where the rail was to be cut. 

After checking my measurement more than three times, I used a dremel power tool and small metal saw to gently cut into the aluminium rail until flush against the edge of the pedestal.  The cut piece of aluminium rail then was able to be removed; however, the rivet body remained.  I then used a metal file to carefully grind away the end of the rivet head until flush with the pedestal side. 

In addition to this, each of the attachment holes of the modules needed to be enlarged slightly to accommodate the male end of a DZUS fastener.  This job was relatively easy and I used a quality drill bit to enlarge the hole.  A word of caution here – SISMO do not use metal backing plates, so if you’re over zealous with a drill you will probably crack the plastic board.

Once the sections of DZUS rails were removed, it was only a matter of dropping the radio modules into the bay and securing them with DZUS fasteners.

System Cards & Wiring – Location, Mounting & Access

I was “surprised’ at the number of cards required to use SISMO modules.  An Ethernet card is required as is a daughter and servo card.  There are also two power sources: 5 volt powers the small servo (motor) that moves the rudder trim gauge, and 12 volt powers the module back-lighting. 

My main concern was where to mount the cards.  Initially, I was going to mount them under the main simulator platform, but access for maintenance was a problem. I decided to utilise the inside of the pedestal beneath the modules.  This area is rather cavernous and a good place to house the cards and wiring needed for the modules (out of sight and out of mind).

LEFT:  SISMO rudder trim and ADF module with power pack.  The rudder trim is quite a good reproduction of the real unit, however, it lacks finesse in its final construction.  I may switch the unit to a CP Flight rudder trim module in the near future.

Constructing an Internal Board – to attach cards to

I cut a piece of thin MDF board to roughly the height of the pedestal interior and fitted it in such a way that it created a vertical partition.  To this board, using both sides, I attached the various cards needed.  To ensure that the flat cables had enough room to reach the various cards, I cut a slot in the center section of the board.  I also made sure there was enough room at each end of the board to allow cabling to snake around the partition. The most important point to remember is to ensure that none of the cards touch the metal sides of the pedestal or each other; to do so will cause an earthing problem. 

Wiring wasn’t much of an issue, as SISMO supplies prefabricated flat wiring with plastic clips.  All you need to do to attach the correct clips to correct attachment point on the card – very easy with absolutely no soldering.  As the Ethernet card is mounted within the pedestal, the only wires that need to be threaded through the lower throttle section of the pedestal are the power cable and the Ethernet cable.  The later connects to the Ethernet switch box that is mounted to the shelf of the FDS MIP.

The pedestal innards are now full of intestinal-looking wires attached to an assortment of cards.  It looks messy with all the wiring, but as the wires are flat wires with solid connectors, it is very secure and logically set out.  Access to the wiring and cards is achieved by removing two or three modules. 

Avionics Modules – A Review

After I have evaluated each of the modules I am using for reliability and functionality, I will post a review as a separate journal post.  I'll also post a few images of the pedestal once the twin ACP units have been fully converted to simulator use.