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Lower Centre Instrument Panel


When designing the instrument panel, I realised there were several items that I didn’t want or need to be on the main panel.

Anticipating this, ages ago I had purchased the brackets F-14188B-L & R and the Sub-Panel Mount F-14188A from the Vans Power Module Option, Manual section 59, hoping I could place these items on this angled panel low down and out of the way.


Well this is the result.

I’ve included the following:

  • CO Detector Status light/button.
  • Vertical Power PPS Fault lights/reset switches.
  • Alternate Static Selector.
  • Joystick Enable Switch.
  • Flap Cut Off Switch.
  • Trim Disconnect Switches.
  • Standby Trim Rocker Switches.

Trim Cut-Off

Non-UK builders will probably be wondering why on earth would you need the trim and flap switches? Here in the UK, our regulator (Light Aircraft Association, LAA) which authorises permits to fly, requires a means to isolate the trim and flap functions if these items are controlled by a computer.

Since the Flaps and Trim are controlled by the Garmin GAD27 computer, I need to comply with the requirements.

Whilst designing the wiring to isolate the trim, I decided to include the Ray Allen rocker switches to enable a Standby Trim, so that the trim can be reversed and independently controlled in the unlikely event of a trim runaway.

Hearing that the RV14 pitch trim is powerful encouraged me to do this … I’m sure the standby aileron trim is an overkill, since I’m guessing the out of trim roll forces could be easily manually controlled … but for the sake of two extra switches I decided to keep the LAA happy!

Joystick Enable Switch

I’ve noticed several builders have included a switch to disable the right stick switches to prevent inadvertent selection by a passenger.

Initially I hadn’t planned to include such a switch, but I’ve come round to the idea for two reasons:

  • We will undoubtedly fly lots of non-aviator passengers, and since the sticks have several controls a means to isolate the right stick is not a bad idea.
  • If a stick develops a switch fault which leaves a switch permanently ON, eg stuck PTT, an isolate switch instantly removes the problem. Hence the switch is wired to isolate the left stick as well.

Of course all this means you have to wire the joystick grounds through an extra switch, involving another failure point. But I’ve used the opportunity to provide redundant ground paths for the sticks via the switch, so I think the extra risk is mitigated and the benefit makes it worthwhile.


The lower panel will have to be removed to access the fuel pump/filter, so I’ve routed the wiring through a DSub connector for easy removal.

I made a little bracket to secure the “aircraft” connector.

I’ve used a MOLEX connector to handle the flap power which is too high for DSub pins.


More wires to be tamed behind this panel, which has proved challenging to ensure it’ll all fit.


I modified a CONNEC DSub housing to allow the fitment of brass threaded studs, which will allow the aircraft/panel connectors to be screwed together for security.


Here are the wires more under control, routed to ensure clearance behind the panel.

I ended up doing this twice, since my first attempt just didn’t give enough clearance.

In the midst of all this I managed to pull out a wire from the rear of the GD40 CO Detector bi-colour LED … Foohey Fudge Cake!

An email to the GD40 company produced an almost instantaneous reply, telling me “it was my lucky day!” since they source the specialised LED’s from a UK company … : ) So for once it was easy to get another sent, which amazingly arrived the following day.

Here is the panel fitted.


3 comments on Lower Centre Instrument Panel
  1. Peter

    That is beautiful! Curious how the site line is to the fault lights?

  2. Steve

    Hi Peter

    Thanks for your kind comment!

    The fault lights are just hidden by the F-14107-1 CONTROL CABLES BRACKET. I eventually decided to go ahead with this design for the following reasons:

    1. The CO Monitor light indicates the CO status, and will normally be a steady GREEN. I’ve been used to a “quiet, dark cockpit” when everything is normal, so I didn’t want to continually look at a light shining at me from the main instrument panel. If a CO alert occurs, it will be announced aurally and also shown on the PFD’s as a caution. A slight dip of the head will reveal the CO LED to confirm the status.

    2. The other two LED’s indicate the status of the PPS. One LED indicates a Battery Distribution Fault, causing the main bus to be isolated, emulating an 80A ANL fuse blowing. This will be very obvious, with most items lost apart from those powered by the standby battery. It won’t require continually monitoring the relevant LED! Similarly the other LED indicates an Alternator Distribution Fault, which will trip a warning on the PFD due to the bus voltage dropping to Battery Voltage.

    If you are considering a similar centre instrument panel, but displaying other fault lights which are important to be continually monitored, I think you would have to move them lower down to see them below the throttle/mixture etc bracket without dipping your head.

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