Summary
We propose to adopt a new airworthiness directive (AD) for certain GARMIN International (GARMIN) GSM 85 servo gearbox units that are installed on airplanes. This proposed AD would require you to inspect the GSM 85 servo gearbox for foreign object debris and return the unit to the manufacturer for replacement if you find debris. This proposed AD results from reports of certain GARMIN GSM 85 servo gearbox units that have foreign object debris inside the assembly. We are proposing this AD to detect and correct defective GARMIN GSM 85 servo gearbox units, which could result in jamming of the gearbox. Jamming of the gearbox could lead to the pilot having to apply excessive manual force to control the airplane.