Serious question about the new digital autopilots

I was real skeptical when my boss told me to swap out the old King KAP 140 for the Garmin GFC 500. Figured it was just another expensive gadget that'd fail in the field. But after doing three installs in the last six months, one on a Cessna up in Anchorage, I gotta say the thing holds a heading way better than I expected. The self-test feature caught a bad servo on the bench too, saved me a trip back out to the ramp. Has anyone else had luck with these new servos, or am I just getting easy birds?

3 comments

3 Comments

vera_lewis1mo ago

Honestly, you're kinda mixing up two different things there. The GFC 500 uses Garmin's own brushless servos, not the old KAP 140 style ones. The self-test feature is nice, but it's actually the GSU 25C ADAHRS unit doing the heavy lifting for the heading hold, not the servo itself. I've seen those servos fail after 50 hours if the install isn't perfect with the wiring shielding, so your luck might just be on those easy birds.

christopher4021mo ago

@the_henry you're reading the datasheets way too literally - the shielding matters but most failures are actually from overheating the servo motor on long holds, not wiring noise. The real devil's advocate take is that the self-test feature just masks bad install habits instead of fixing them.

the_henry1mo ago

Wait wait wait, you're saying those brushless servos actually start dying after 50 hours if the shielding isn't perfect? That's wild because I've been treating the wiring like it doesn't matter much beyond keeping it clean. I guess I better double-check my install logs before those birds go back to the owner.