Transport Transports 

# 1*1 Canada Canada No. CF-2007-25R1 Issue Date 13 February 2008 

# AIRWORTHINESS DIRECTIVE - - - 

### - - - - - -- The idlawing airworlhlnessdlrectlve (AD) my be appllcabk lo an alrcrafl which our records indlcate Is registered In your name. A& are Issued plrsuent lo CanadIan AvlaUon RegulaUon (CAR) 593. Pursuantto CAR 605.84 and lhe further details of CAR Standard 625 Appendlx H lhe conUnulng alrworthlness of a Canadlan registered aircraft is contingent upon wmpllance wilh all applicable ADS. Failure to conply with lhe requireme;lts of an my invalidate the flight aulhonzatlon of the airuafl. Alternative means of conpllance shall be appliedfor Inaccordancemth CAR 805.84 and the above-referencedStandard. Thhs AD has been issuedby lhe Continuing Airworthiness Divlsion (AARDG), A~rcrafl CerliRcatlon Branch, Transport Canada. Ollawa, telephone 613 952-4357. Number: Subject: Effective: Revision Applicability: Compliance: Background:

Corrective Actions: PW305Aand PW305B Engine High Pressure Compressor (HPC) Drum Rotor Cracks 29 October 2007 Supersedes Airworthiness Directive (AD) 2007-25 dated 29 October 2007 and is issued to correct a typographic error in paragraph "3." of the "CorrectiveAction". All post SB 24287, PW 305A and PW 3058 Engines without SBPW300-72-24376 incorporation As indicated in the "Corrective Action" per this directive, unless already accomplished P&WC has determined that the Post-Service Bulletin (SB) PW300-72- 24287 High Pressure Compressor (HPC) drum rotor assemblies PIN 3082478 and 3082542 on PW 305A and 3058 engines with single stage coated labyrinth seals, are susceptible to developing significant cracks inthe region of the labyrinthseal. P&WC issued SB PW300-72-24462 for initial inspection of affected HPC drum rotor assemblies for cracks. In addition, the PW305 Maintenance Manual (MM) 05-20-00 was revised (Revision No.26) accordingly, to add requirement for repeat inspection interval. A new PIN 3186325-01, HPC drum rotor assembly, which is not susceptible to subject cracking, is made available through SB PW300-72-24376, as terminating action for the required repeat inspection. Recent data (Ref: SIL: PW300-093) indicate that 

### a number of high-time Pre-SB-PW300-72-24376 HPC drum rotor assemblies (PINS 3082478 and 30B2542), with potential for a hazardous disk failure in consequence of non-compliancewith the inspection requirements, are still in-service. This AD is issued to mandate the inspectionof the affected PIN 3082478 and 3082542 HPC drum rotor assemblies in accordance with PW305-MM-05-20-00 requirements.

On all PW305A and PW305B engines with post SB PW300-72-824462 HPC drum rotor assemblies PINS30B2478 and 3082542, accomplish the following: 1. Within 500 hours airtime after effective date of this directive, gain access to insideof affected HPC rotor assembly and inspect (boroscope) its interior for cracks in accordance with the PW305 MM 05-20-00 "Periodic Inspections, Boroscope" requirements. If a crack is found, remove the engine before nextflight for HPC drum rotor replacement. Note: Inspectionofaffected HPCdrum rotor assemblyper SB PW300-72-824462 and/or PW305MM05-20-00 requirementsprior to the effective date ofthis directive satisfies the requirementsof paragraph 

### I ofthis directive.

Puouant to CAR 202.51 the registeredowner of a Canadlanalrcraflshall, within seven days, nolify lhe Mlnlster inwilingof any change of his or her name or address. To request a chan e of address, contactthe ChrllAvbUonComrnunlcatlom Centre (AARC) at PlacedeVllle. kwa.Ontarlo KlAONI. or 1-800-305-2059, orwww.tc.gc~c~lbvbUonlcorrrrmnluUondee addressasp2. Repeat boroscope inspection per paragraph 1

### ., at interval not exceeding 1350 flight cycles per PW305 MM 05-20-00. If a crack is found, remove the engine before next flightfor HPC rotor drum replacement. 3. Replacement of the affected HPC rotor assembly PIN 3082478 or 3082542 with Post-SB PW300-72-24376 assembly PIN 3166325-01or later superseding PIN, will constitute terminating action for the inspection requirements of the above paragraphs 1 and 2 of the corrective action requirements of this directive. Authorization: For Minister of Transport, Infrastructure and Communities

Derek Ferguson Acting Chief. ContinuingAirworthiness Contact: Mr. A 

### K Durrani, ContinuingAirworthiness, Ottawa, telephone (613) 952-5385, facsimile (613) 996-9178 or e-mail durrana@tc.gc.ca or any Transport Canada Centre