Populating the B737 Center Pedestal

oem 7373400 center pedestal (two bay). avionics include cp flight, flight deck solution and oem. this pedestal has since been replaced with a three bay pedestal

The centre pedestal I’m using is a real aviation part procured from a South West 737-300 series aircraft. The pedestal came attached to the throttle quadrant and is the more uncommon two bay style. The Next Generation uses a three bay center pedestal.

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 bay pedestal and limit myself only to essential avionic modules.

Apart from the nostalgia of using an OEM pedestal, I really like the DZUS rails that are used in a OEM pedestal, which allow you to drop the various panels into place and secure them with a DZUS fastener. To read about DZUS fasteners, navigate to my earlier post.

In this post I will discuss populating the center pedestal with panels, and touch on using the panels from a comparative newcomer - SISMO Solicones. I will also discuss some of the problems I had with installing reproduction panels to the OEM center pedestal.

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 737s were fitted with a two bay center pedestal which minimised the number of panels that could be fitted. Later model 737 aircraft and the Next Generation aircraft series use a three bay center pedestal that enables installation of the latest navigation and communication equipment. There are benefits to the thinner two bay pedestals, the main positive being more room to climb into the flightdeck.

All 737s 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 panel - perhaps with the exception of the fire suppression panel 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 have 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.

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 standardise everything across their simulator. This is not necessary; it is realistic if you mix-match panels to a certain degree.

This pedestal is mounted within a 737-700 aircraft and represents the more usually found three column pedestal in this series aircraft.

The center pedestal is populated 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) - replaced with Flight Deck Solutions.
ADF-2 (CP Flight) - replaced with Flight Deck Solutions.
Rudder Trim (CP Flight) - replaced with OEM.
ATC (transponder) (CP Flight) - replaced with OEM.
Fire Suppression Module (OEM 737-400 converted for FS use) - replaced with 737-600 NG.
Audio Control Panel (2) (ACP) (OEM 737-400 unit – at the moment, wired only for backlighting)

Avionics Mania

Unless you have an unlimited budget, or have panel sickness, you may want to think about how often you will use a particular panel. 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 panel 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.

This is a side benefit to using a two bay center pedestal: there is only so much room available, so you are forced to decide on which panels take precedence over others.

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 at the time of writing, manufacture and sell an ADF navigation radio panel. Further, FDS do not produce the older style ATC (transponder) panel; they only manufacture the newer push button type, and I favoured the older style.

As the MCP I am using is manufactured from CP Flight, and I also have an older style CP Flight transducer, I decided to opt for the CP Flight ADF navigation radios. CP Flight have an easy method to daisy chain panels together. Unfortunately due to supply issues this was not to be the case.

OEM Panels

Nothing beats OEM panels and I am hoping in time to replace many of the reproduction panels with OEM components. In the meantime, I will be using reproduction panels.

SISMO Solicones

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 OEM panels, use Ethernet rather than USB, and relatively easy to configure.

I was very keen to trial Ethernet as a method to connect the modules to the computer.

SISMO SOLICONES. Note the electronics tab that needs to clear the DZUS rails for installation. A poor panel design if using an OEM center pedestal

Module Size – Size Matters!

It’s very important to check that the panel will fit correctly to whatever pedestal you are using. If you are building your own pedestal without rails, then this is not an issue as you can easily fashion a template to drop the panels into. However, if you are using an OEM panel, you will need to ensure that the panels 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.

ADF Navigation Radio Panels – Attaching to the DZUS Rails

The avionics panels made by Flight Deck Solutions are literally drop & forget as all FDS panels are DZUS compliant and fit OEM DZUS rails perfectly. The ADF radios from SISMO are a different matter. Each of the panels has a small tab on the electronics board which is too wide to navigate past the DZUS rail in the pedestal. This is a major issue as the panel cannot be dropped onto the rails. Why SISMO designed them this way is beyond me, as many serious simmers use OEM 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 panels. 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 panel to then be dropped into the pedestal.

OEM 737-300 CENTER PEDESTAL WITH RAIL CUT TO ENABLE REPRODUCTION PANEL TO BE INSTALLED

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 triple checking the measurements, 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 panelss needed to be enlarged slightly to accommodate the male end of the OEM 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 panels into the pedestal and securing them with DZUS fasteners.

SISMO SOLICONES rudder trim and ADF module with power pack. The rudder trim is A MEDIOCRE reproduction of the real unit. however, it lacks finesse in its final construction. I DO NOT RECOMMEND USING THESE PANELS

System Cards & Wiring – Location, Mounting & Access

I was very surprised at the number of cards required to use SISMO panels. An Ethernet card is required as is a daughter and servo card. There are also two power sources: 5 volt powers the small servo moto) that moves the rudder trim gauge and 12 volts powers the module backlighting.

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).

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.

Update

on 2012-07-25 05:48 by FLAPS 2 APPROACH

After trialling the panels manufactured by SISMO, I wasn't impressed. The ADF navigation radio gave spurious results which were intermittent, and the frequency change switch did not provide consistent operation - sometimes it worked and at other times it was sticky and needed to pressed a few times to initiate the frequency change.

The rudder trim module also did not work correctly, even with the correct SC Pascal script.

The Transponder ATC module looked OK, but never worked as a script was not supplied. The Audio Control Module looked absolutely awful with poor quality switches and cheap and nasty-looking plastic buttons.

Rather than fight with cards, wires, and a software medium (SC Pascal scripts) which I don't have the knowledge to edit, I decided to box everything and send it back to SISMO for refund.

The SISMO panels have been replaced with panels made by CP Flight and OEM panels.