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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)
« NAV 1/2 & M-Comm Radios by Flight Deck Solutions - Review | Main | Look Dad - No Mouse! - CP Flight PRO MCP & EFIS Installed »

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.

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Reader Comments (1)

Good Morning - I also bought SISMO products as they had nice service and pictures look good on website. I was not happy with my purchase as modules were not made to good looking specification. SC Pascal script also was problematic when running Pro Sim 737. I am very sorry I bought from SISMO and do not recommend this company. Buy CP Flight or Open Cockpit. Good website. Hans from Mainz , Germany

May 24, 2012 | Unregistered CommenterHans Muller
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