Airworthiness Directives; Pilatus Aircraft Ltd. Models PC-6, PC-6-H1, PC-6-H2, PC-6/350, PC-6/350-H1, PC-6/350-H2, PC-6/A, PC-6/A-H1, PC-6/A-H2, PC-6/B-H2, PC-6/B1-H2, PC-6/B2-H2, PC-6/B2-H4, PC-6/C-H2, and PC-6/C1-H2 Airplanes

We are adopting a new airworthiness directive (AD) that supersedes AD 98-12-01, which applies to certain Pilatus Aircraft Ltd (Pilatus) Models PC-6, PC-6/A, PC-6/B, and PC-6/C series airplanes equipped with turbo-prop engines. Since we issued AD 98-12-01, the FAA determined the action should also apply to all the models of the PC-6 airplanes listed in the type certificate data sheet of Type Certificate (TC) No. 7A15 that were produced in the United States through a licensing agreement between Pilatus and Fairchild Republic Company (also identified as Fairchild Industries, Fairchild Heli Porter, or Fairchild-Hiller Corporation). In addition, the intent of the applicability of AD 98-12-01 was to apply to all the affected serial numbers of the airplane models listed in TC No. 7A15. This AD retains all the actions of AD 98-12-01, adds those Fairchild Republic Company airplanes to the applicability of this AD, and lists the individual specific airplane models. We are issuing this AD to prevent engine fuel starvation during maximum climb and descent caused by poor fuel tank venting with low fuel levels, which could result in a loss of engine power during critical phases of flight.