Summary
The FAA proposes to adopt a new airworthiness directive (AD) for Honeywell International Inc. auxiliary power units (APU) models GTCP36-150(R) and GTCP36-150(RR). This proposed AD would require inspecting the fuel control unit (FCU) differential pressure (Delta P) sleeve bore for erosion, replacing the FCU if it fails the inspection, and installing a fuel deflector on the Delta P sleeve of the FCU. This proposed AD results from eight reports of fuel leakage from the fuel control unit. We are proposing this AD to prevent fuel leakage in the APU compartment, which could lead to ignition of fuel vapor, creating a fire and explosion hazard resulting in injury, and damage to the APU and the airplane.