Garmin’s service alert applies to owners and operators of certified aircraft with G3X Touch or GI 275 engine display installations that are connected to a GEA 24 engine indication system that is, in turn, interfaced with resistive fuel senders.
When operating at low fuel, the G3X Touch and GI 275 fuel quantity gauges may erroneously indicate remaining fuel. The indication error can be a difference of up to 4 gallons, more or less, from the actual quantity remaining. The fuel quantity error increases when the fuel senders have small resistance ranges, and when the GEA 24 is subject to significant temperature changes.
The error only occurs if a GEA 24 is installed and connected to resistive fuel senders with a range of less than or equal to 100 ohms. The service alert provides guidance to determine which installations may be affected, and what actions to take.
Garmin Aviation Media Relations Specialist Conor McDougall told AOPA that G3X Touch for Experimental Aircraft installations are not affected. Likewise, GI 275 EIS installations using the GEA 110, typically in Class III aircraft weighing 6,000 pounds or more, are also not affected.
Garmin warned operators who are using affected equipment to expect a fuel indication error of up to 4 gallons per tank for all operations. Displays may indicate up to 4 gallons remaining when no useable fuel remains.
Garmin said it will provide additional information for an improvement to fuel quantity indication accuracy when available.