Just a post to help anyone out who may also be having problems with their G5 showing inconsistent heading.
A while ago I bought a Piper Arrow that had dual G5s and a 430w installed previously. The G5s were installed about a year before I bought the plane. After about 10 hours of flying it I noticed that the G5s were now indicating a heading inconsistent with magnetic compass of about 60-100 degrees. I went through the software upgrade on the G5s at the instruction of Garmin support which did not resolve the issue. I also tried calibrating the G5 magnetometer using the process described in the manual. None of those fixed the issue. Digging deeper, I found out that the magnetometer GMU-11 was installed in the wing tip. I picked up a cheap borescope from Amazon and peaked in through the wingtip light hole and found the GMU-11 laying on the inner wing without being attached to its mount. It turns out the GMU-11 was installed without any sort of locking nuts on the mount so after a year of vibration the nuts backed off and the GMU-11 worked its way free.
A while ago I bought a Piper Arrow that had dual G5s and a 430w installed previously. The G5s were installed about a year before I bought the plane. After about 10 hours of flying it I noticed that the G5s were now indicating a heading inconsistent with magnetic compass of about 60-100 degrees. I went through the software upgrade on the G5s at the instruction of Garmin support which did not resolve the issue. I also tried calibrating the G5 magnetometer using the process described in the manual. None of those fixed the issue. Digging deeper, I found out that the magnetometer GMU-11 was installed in the wing tip. I picked up a cheap borescope from Amazon and peaked in through the wingtip light hole and found the GMU-11 laying on the inner wing without being attached to its mount. It turns out the GMU-11 was installed without any sort of locking nuts on the mount so after a year of vibration the nuts backed off and the GMU-11 worked its way free.
