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 name. 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 may 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 by the Continuing Airworthiness Division (AARDG), National Aircraft Certification Branch, Transport Canada, Ottawa, telephone 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 

24-0022 (01-2005)

1/2 No.

CF-2013-21R1

Issue Date 

 31 October 2013 

Number: CF-2013-21R1 

Subject: Compressor Turbine (CT) Blade Failures 

Effective: 13 November 2013 

Revision Supersedes AD 2013-21, issued 1 August 2013. 

Applicability: Pratt & Whitney Canada model PT6A-114 and PT6A-114A engines, with Pre-SB

1669 or Pre-SB 1727 Configuration CT Blades Installation. 

Compliance: As indicated below, unless already accomplished.

Background: There have been a number of reported incidents where Compressor Turbine (CT) blades 

failures have caused power loss on PT6-114 & PT6A-114A engines, resulting in in-flight 

shutdown (IFSD). Investigation by engine manufacturer Pratt & Whitney Canada (P&WC) 

has determined that when operated at high power and high temperature settings, the 

subject CT blades are prone to crack/fracture as result of creep and/or sulfidation. 

P&WC issued Service Bulletin (SB) 1669 that introduces a newly designed CT blade 

which has proven to be far less affected by the blade “Creep” phenomenon. Additionally, 

to help prevent IFSD by identifying pending Creep induced blade failure of the 

pre-SB 1669 configuration blades, P&WC has revised the SB 1669 to include specific

inspection/maintenance requirements for engines with pre-SB 1669 configuration CT 

blade installation. 

An engine power loss or IFSD on a single engine powered aeroplane such as Cessna 

208 could result in an unsafe condition. AD CF-2013-21 was issued on 1 August 2013 to

mandate the compliance with SB 1669R9 requirements to inspect and replace the 

existing CT blades on PT6A-114 & PT6A-114A engines with a new type of post SB 1669 

configuration CT blades. P&WC, through SB 1727, has now introduced a new version of 

the post SB 1669 configuration CT blade that features a tighter tolerance on the platform 

width. This enhances the ability of the maintainer to achieve the required inter-platform 

gap. This AD is now revised to include the installation of the new post SB 1727 CT blades 

as terminating action of this AD. 

Corrective 

Actions: 

Part I - For Engines With 500 or More Hours Air Time Since New That Have Not 

Been Previously Inspected Or Have Accumulated More Than 500 Hours Air

Time Since Last Inspection, Per The MM 72-00-00, Table 601 Requirements: 

Within 150 hours of air time from the effective date of this AD, perform a borescope

inspection of the CT blades in accordance with Accomplishment Instructions in 

paragraph 3.A of the P&WC SB 1669R9 dated 28 June 2013 or later revisions approved 

by the Chief, Continuing Airworthiness, Transport Canada.
No.

N° CF-2013-21R1 2/2 

Part II - For Engines That Have Been Previously Inspected Per MM 72-00-00, Table 

601 Requirements: 

At intervals not to exceed 500 hours air time since the last inspection, perform a

borescope inspection of the CT blades in accordance with the Accomplishment 

Instructions in paragraph 3.A of the P&WC SB 1669R9 dated 28 June 2013 or later 

revisions approved by the Chief, Continuing Airworthiness, Transport Canada.

Part III - For All Affected Engines: 

During the next engine Hot Section Inspection (HSI) as of the effective date of this AD; 

submit a two-CT blade sample in accordance with Accomplishment Instructions in 

paragraph 3.B of the P&WC SB 1669R9, to P&WC approved overhaul facility for 

metallurgical evaluation. If the evaluation results are not satisfactory, replace the 

complete set of CT blades with Post-SB 1669 or Post-SB 1727 CT blades, in accordance 

with either paragraph 3.C of the P&WC SB 1669R9 dated 28 June 2013 or the 

Accomplishment Instructions in SB 1727 dated 23 August 2013, or later revisions of either 

SB approved by the Chief, Continuing Airworthiness, Transport Canada. 

Part IV - For All Affected Engines: 

Within 36 months as of the effective date of this AD, replace all existing CT blades with 

new CT blades P/N 3072791-01 or P/N 3072791-02 and/or replace the Compressor 

Turbine Disk Balancing Assembly with new P/N 3072801-01 or P/N 3072801-02 as 

required, in accordance with either the Accomplishment Instructions in paragraph 3.C of 

the P&WC SB 1669R9 dated 28 June 2013 or the Accomplishment Instructions in 

SB 1727 dated 23 August 2013, or later revisions of either SB approved by the 

Chief Continuing Airworthiness, Transport Canada.

Compliance with Part IV of this AD constitutes terminating action of this AD. 

Compliance with earlier versions of SB 1669 prior to the effective date of this AD also 

meets the Part IV requirements of this AD and constitutes terminating action of this AD. 

Authorization: For the Minister of Transport, 

ORIGINAL SIGNED BY 

Derek Ferguson 

Chief, Continuing Airworthiness 

Contact: A K Durrani, Continuing Airworthiness, Ottawa, telephone 613-952-4357, facsimile 

613-996-9178 or e-mail AD-CN@tc.gc.ca or any Transport Canada Centre.