AA5BY

Confidence means a lot... when a valued plane is dependent upon the reliable performance of the control equipment. Kinda hard to have fun, with worry on the mind.

I had an event with my XG-8 that chipped a little crack in the confidence. On the base leg of a landing approach, the plane suddenly rolled and while some effort helped, adequate control was lost so I cut the power and it went in and wiped out the front section, rudder, bent the wing tube, ripped out a root rib, wing tips and minor abrasions. Though I and others hadn't thought it had gotten too slow to stall, there was a cross wind in our face and we suspected a tail wind gust hit it and it stalled.

A year later after rebuilding, the cause was discovered. When hooking the choke and throttle servos up, it was powered up for the first time since the crash. I activated the gear switch to move the choke and it didn't move, but something was moving... what was it? I'd taken the stabs off when doing the repairs and discovered that it was the elevator servos that were responding to the gear switch. In pos 0, they went hard over in opposite directions. Pos 1 they centered and in pos 2, they went hard over again opposite to pos 0. edit note: the choke was actually on the aux 2 ch and I'd forgotten.

There were no mixes or reasons why the gear switch should affect the elevators, more especially the primary elevator. The gear ch was slaved to the elevator ch but that is supposed to render the gear ch unresponsive to the gear sw. The instruction manual even illustrates doing so. Finding no way to stop it, the gear ch was unmated from the elevator ch in the wing configuration screen. At that point, operation seemed normal, the gear switch no longer had control of the elevator ch.

When mating the gear ch back again to the elevator, operation was normal with the gear sw having no effect upon either the elevators. Horizon offered that unless the problem could be duplicated, they had nothing to fix and suggested upgrading to latest firmware, which I did as well as change the elevator slave from the gear ch to the aux 2 ch and put the choke on the gear ch.

My only explanation is that it was what the electronics industry calls a single event upset. I'd flown the plane for a year with that config and have now flown another plane for two years with the same config.

Is there a slight crack in confidence... yes.