The FAA has issued AD 2004-13-20 which will become effective August 03, 2004.
The AD applies to aircraft equipped with Garmin AT Apollo GX50, GX55, GX60 and GX65 global positioning system (GPS) navigation units with software version 3.0 through 3.4 certificated in any category. Units with the above software installed will have to be either returned to Garmin for a software update or, updated at an authorized Garmin dealer. Wings desiring not to return units to Garmin may contact NHQ/LGM for their closest authorized Garmin dealer. Garmin will not pay freight costs to ship units for repair. However, they will update the unit and return ship it under warranty. See above attachment for instructions to determine the current software version of these units. Questions may be directed to NHQ/LGM, 334-953-6032, or Garmin at 800-525-6726.