Lower Centre Instrument Panel

IMG 6334

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.

IMG 6332

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.

IMG 6350

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

IMG 6351

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.

IMG 6364

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.

IMG 6359

1 Comment on "Lower Centre Instrument Panel"

  1. Really nice Steve.

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