EASA AD US-2022-03-15: Fuel - Resistive Fuel Probe Interface - Modification

What to do

Operators of affected airplanes must modify the resistive fuel probe interface and recalibrate the fuel system following the procedures in Garmin Mandatory STC Service Bulletins 2134 and 2135. The modification must be completed by March 21, 2022, the effective date of the AD. Stakeholders should contact Garmin Aviation Support for service information and coordinate with FAA representatives for compliance verification.

Summary

Federal Aviation Administration Airworthiness Directive AD 2022-03-15 is a final rule addressing various airplanes modified with Garmin G3X Touch Electronic Flight Instrument System installed under STC No. SA01899WI or Garmin GI 275 Multi-Function Display installed under STC No. SA02658SE. The directive targets fuel quantity indication errors caused by the resistive fuel probe interface, which can lead to inaccurate fuel readings. This AD applies to multiple aircraft models equipped with these Garmin systems and aims to ensure accurate fuel quantity display.

What changed

This new airworthiness directive requires modifying the resistive fuel probe interface on affected airplanes to correct fuel quantity indication errors caused by temperature-related resistance changes in the fuel probe circuitry. The FAA revised the applicability to exclude certain airplane models not subject to the unsafe condition and clarified the nature of the fuel quantity error and its consequences. The AD introduces mandatory modification procedures as specified in Garmin Mandatory STC Service Bulletins 2134 and 2135.

Why it matters

Accurate fuel quantity indication is critical for safe flight operations to prevent fuel starvation and potential engine shutdown. This AD addresses a known issue that could cause pilots to overestimate fuel onboard, risking inability to reach the destination or alternate airport. Compliance ensures operators maintain regulatory safety standards and avoid operational disruptions or safety incidents related to fuel mismanagement.