What would cause a Cessna 182T G1000 to show red X's on Manifold, Fuel, M & S Batt Amps?

Question

Our 2006 Cessna 182T G1000 suddenly started showing the following X's on Manifold, Fuel, and M/S Batt Amps. You can see in the second photo, that the batteries are charging when the plane is started. No other issues it seems, and of course it's grounded till we figure it out.

I would think those 3 systems are completely independent of one another, except tied together by the GEA 71 unit. We checked terminals, connections, swapped PFD/MFD screens. The system check seems to suggest the GEA 71 checks out OK, but those 3 systems obviously are failing.

Any other ideas of what to look at next, aside from trying to put in a new GEA 71 and hope that solves it? Don't want to just throw new components at it though.

Answer 1

It's pretty simple. If you want to avoid swapping out the GEA71 with a known good unit to see what happens, the way an airline would normally do it when they have spares on hand, you have to go digging around the old fashioned way first, and figure out which pins on P701 and P702 are being used for those input/outputs, and start checking back through the wiring to the source units with a DMM.

You need a wiring diagram that shows the wiring between the GEA 71 and the source hardware.

You aren't going to have those components all stop providing signals independently at the same time, so clearly there is either:

• The failed source component wires all pass through the same terminal block or bulkhead connector and there is open connection for all those circuits.
• Those inputs are processed by particular common circuit board inside the GEA 71 and that board has gone south, although you would normally expect that to show up during the unit's diagnostic or startup BITE.

So if it passes all BITE tests, you simply work back through the wiring looking for a common failure point, and if you can't find anything amiss, well maybe the BITE doesn't catch it, and it's time to swap out the box.