Airworthiness Directive · Amendment 39-17961 · Pratt & Whitney Canada Corp. Turboprop Engines
Pratt & Whitney Canada Corp. Turboprop Engines
Superseded. A later AD replaced this one: AD 2014-17-08 R1. Comply with the one in force.
This AD applies to all Pratt & Whitney Canada Corp. (P&WC) PT6A-114 and PT6A-114A turboprop engines.
We are adopting a new airworthiness directive (AD) for all Pratt & Whitney Canada Corp. (P&WC) PT6A-114 and PT6A-114A turboprop engines. This AD requires initial and repetitive borescope inspection (BSI) of compressor turbine (CT) blades, and the removal from service of blades that fail inspection. This AD was prompted by several incidents of CT blade failure, causing power loss, and engine failure. We are issuing this AD to prevent failure of CT blades, which could result in damage to the engine and damage to the airplane.
(1) For engines that have CT blades installed other than P&WC single crystal CT blades, part numbers (P/Ns) 3072791-01 or 3072791-02, perform the following actions:
(i) Within 150 operating hours after the effective date of this AD, perform a borescope inspection (BSI) of CT blades for engines with 500 or more hours time-since-new that have not been previously inspected or time-since-last-inspection (TSLI).
(ii) Thereafter, repeat the inspection in paragraph (e)(1)(i) of this AD within 500 flight hours TSLI.
(iii) During the next hot section inspection (HSI) after the effective date of this AD, and each HSI thereafter, replace the complete set of CT blades with any of the following:
(A) New CT blades;
(B) CT blades that have passed a two-blade metallurgical examination in accordance with paragraph 3.B., Accomplishment Instructions, of P&WC Service Bulletin (SB) No. PT6A-72-1669, Revision 9, dated June 28, 2013; or
(C) P&WC single crystal CT blades, P/Ns 3072791-01 or 3072791-02.
(2) Reserved.
Within 36 months after the effective date of this AD, replace the complete set of CT blades with P&WC single crystal CT blades, P/Ns 3072791-01 or 3072791-02.
If you performed a metallurgical examination of single crystal CT blades before the effective date of this AD in accordance with P&WC SB No. PT6A-72-1669, Revision 8, dated January 17, 2013, or earlier versions, all of which are not incorporated by reference, you have met the initial inspection requirements of paragraph (e)(1)(i) of this AD. However, you must still comply with the repetitive BSI requirement of paragraph (e)(1)(ii) of this AD.
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.
