In November 2022, Garmin released a service alert that said the GFC 500 with an optional GSA 28 pitch trim servo for experimental, light sport, and certified aircraft had an issue that could cause runaway nose-up trim the first time the autopilot was engaged. Aircraft owners and operators were instructed to disable the autopilot by pulling the unit, collaring the circuit breaker, and placarding the unit as inoperative. The unit then could be taken to a Garmin repair station to have the auto trim disabled and reinstalled in the interim. The issue did not affect autopilots installed in Cirrus SR20 and SR22 aircraft.
The AOPA Air Safety Institute issued a safety alert on this issue, advising affected owners to review the relevant instructions to mitigate the risk of runaway trim.
The software fix is expected to be available within the next several weeks, Garmin said. Once it’s out, owners and operators must accomplish the fix within six months or at the next scheduled service interval, whichever occurs first.
The modification may be reimbursed under warranty with a deadline of June 30, Garmin said.
While the FAA is the first to sign off on the software fix, Garmin said it continues to work with European, U.K., and Brazilian aviation regulatory agencies to validate the software installation approval and will issue updates pertaining to those regions as they become available.