Airworthiness Directives; Pilatus Aircraft Ltd. Models PC-7, PC-12, and PC-12/45 Airplanes

The FAA adopts a new airworthiness directive (AD) that supersedes AD 2002-01-09, which applies to all Pilatus Aircraft Ltd. (Pilatus) Models PC-7, PC-12, and PC-12/45 airplanes that incorporate a certain engine-driven pump. AD 2002-01-09 currently requires you to inspect the joints between the engine-driven pump housing, the relief valve housing, and the relief valve cover for signs of fuel leakage and extruding gasket material; replace any engine-driven pump with any of the above problems; and ensure that the relief valve attachment screws are adequately torqued and re-torque as necessary. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. This AD retains the actions from AD 2002-01- 09, adds certain engine-driven pumps to the applicability, and requires eventual replacement of the pump with an improved design pump to assure that the unsafe condition does not recur. We are issuing this AD to detect and correct gasket material extruding from the engine-driven pump housing and detect and correct relief valve attachment screws with inadequate torque. These conditions could lead to fuel leakage and result in a fire in the engine compartment.