Airworthiness Directive · Amendment 39-14665 · 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
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
This AD affects the following 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 that are equipped with turbo-prop engines and certificated in any category:
(1) Group 1 (maintains the actions from AD 98-12-01): All manufacturer serial numbers (MSN) up to and including 915.
(2) Group 2: MSN 2001 through 2092.
Note: These airplanes are also identified as Fairchild Republic Company PC-6 airplanes, Fairchild Heli Porter PC-6 airplanes, or Fairchild-Hiller Corporation PC-6 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.
To address this problem, you must do the following:
| Actions | Compliance | Procedures |
|---|---|---|
| (1) Modify the fuel system to improve the venting between the collector tank, the main wing tanks, and the engine | (i) For Group 1 Airplanes: Within the next 3 calendar months after July 13, 1998 (the effective date of AD 98-12-01), unless already done (ii) For Group 2 Airplanes: Within the next 3 calendar months after August 7, 2006 (the effective date of this AD, unless already done | Follow Pilatus PC-6 Service Bulletin No. PC-6-SB-171, dated October 18, 1995. |
| (2) Do not install any collector tank or fuel vent system unless the modification requirements of paragraph (e)(1) are done | For all airplanes: As of August 7, 2006 (the effective date of this AD) | Follow Pilatus PC-6 Service Bulletin No. PC-6-SB-171, dated October 18, 1995. |
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
