### Transport Transports Canada Canada TP 7245E



# AIRWORTHINESS DIRECTIVE

The following airworthiness directive (AD) may be applicable to an aircraft which our records indicate is registered in your na me. ADs are issued pursuant to Canadian Aviation Regulation (CAR) 521 Division X . Pursuant to CAR 605.84 and the further details of CAR Standard 625, Appendix H , the continuing airworthiness of a Canadian registered aircraft is contingent upon compliance with all applicable ADs. Failure to comply with the requirements of an AD ma y invalidate the flight authorization of the aircraft. Alternative means of compliance shall be applied for in accordance with CAR 605.84 and the above-referenced Standard

. This AD has been issued b y the Continuin g Airworthiness Division ( AARDG ) , National Aircraft Certification Branch, Trans p ort Canada, Ottawa, tele p hone 613 952-4357.

Pursuant to CAR 202.51 the registered owner of a Canadian aircraft shall, within seven days, notify the Minister in writing of any change of his or her name or address. To request a change of address, contact the Civil Aviation Communications Centre (AARC) at Place de Ville, Ottawa, Ontario K1A 0N8 , or 1-800-305-2059
, or www.tc.gc.ca/civilaviation/communications/centre/ address.asp

2 4-0022 ( 01-2005 ) 

### 1/1 No

. 

### CF-2013-33R1 Issue Date 

### 14 November 2013

Number: CF-2013-33R1
Subject: Power Turbine Containment Ring Failure

Effective: 28 November 2013

Revision: Supersedes Airworthiness Directive (AD) CF-2013-33, dated 10 October 2013. Applicability: Pratt & Whitney Canada (P&WC): All model PT6A-20, PT6A-20A, PT6A-20B, PT 6A-25, PT6A-28, PT6A-34B, PT6A-36 and PT6A-135 engines; Model PT6A-21 engines, serial number (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-114 engines, S/N PCE-17218 and earlier; Model PT6A-135A engines, S/N PCE-35089 and earlier.
Compliance: As indicated below, unless already accomplished.
Background: There have been in-service events involving the perforation of PT6A small series engine cases as a result of the loss of integrity of Power Turbine (PT) Containment Rings under failure loads. Perforation of engine cases has been seen to result from the liberation of PT blades and from fracture/displacement of the PT Containment Ring itself. In order to minimize future uncontained events, P&WC has issued Service Bulletin (SB) A1427 to modify the PT Containment Ring with better containment capability. This AD mandates the incorporation of SB A1427. Revision 1 (R1) of this AD is issued to correct the issuance date of P&WC SB A1427.

Corrective Actions: Within 24 months, or when the engine or module is at a maintenance base that can perform the procedures, whichever occurs first, from the effective date of this AD, modify the existing PT Containment Ring in accordance with P&WC SB A1427R3, dated 27 January 2012, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada. Incorporation of earlier versions of P&WC SB A1427, prior to the effective date of this AD, also satisfies the requirement of this AD.

Authorization: For the Minister of Transport,

ORIGINAL SIGNED BY
Derek Ferguson Chief, Continuing Airworthiness
Contact: Robin Lau, Continuing Airworthiness, Ottawa, telephone 613-952-4357, facsimile 613-996-9178 or e-mail AD-CN@tc.gc.ca or any Transport Canada Centre.