Airworthiness Directive · Amendment 39-17855 · Pratt & Whitney Canada Corp. Turboprop Engines
Pratt & Whitney Canada Corp. Turboprop Engines
This AD applies to Pratt & Whitney Canada Corp. (P&WC) turboprop engines as follows: all model PT6A-20, PT6A-20A, PT6A-20B, PT6A-25, PT6A-28, PT6A-34B, PT6A-36, and PT6A-135 engines; model PT6A-11 engines, serial number (S/N) PC-E10539 and earlier; PT6A-11AG, S/N PC-E10224 and earlier; PT6A-15AG engines, S/N earlier than PC-E14089; model PT6A-21 engines, S/N PCE-25361 and earlier; model PT6A-25A engines, S/N PCE-48757 and earlier; model PT6A-25C engines, S/N PCE-26258 and earlier; model PT6A-27 engines, S/N PCE-42523 and earlier as well as all engines converted to PT6A-27; model PT6A-34 engines, S/N PCE-57303 and earlier as well as all engines converted to PT6A-34; model PT6A-34AG engines, S/N PCE-57312 and earlier as well as all engines converted to PT6A-34AG; model PT6A-110 engines, S/N PC-E15052 and earlier; model PT6A-112 engines, S/N earlier than PC-E12563; model PT6A-114 engines, S/N PCE-17218 and earlier; and model PT6A-135A engines, S/N PCE-35089 and earlier.
We are adopting a new airworthiness directive (AD) for certain Pratt & Whitney Canada Corp. (P&WC) turboprop engines. This AD requires installing a reinforcement liner to the power turbine (PT) containment ring and, for certain PT containment rings, adding scallops. This AD was prompted by in-service events involving the perforation of engine cases as a result of the liberation of PT blades and the fracture/ displacement of the PT containment ring. We are issuing this AD to prevent uncontained engine failure and damage to the airplane.
(1) Comply with this AD within the compliance times specified, unless already done.
(2) Within 48 months after the effective date of this AD, modify the existing PT containment ring. Use paragraph 2, Accomplishment Instructions, of P&WC Service Bulletin (SB) No. 12076, Revision 3, dated January 17, 1992, or paragraph 3, Accomplishment Instructions, P&WC SB No. PT6A-72-A1427, Revision 3, dated January 27, 2012, as applicable, to make the modification.
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.
