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 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 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 Communicat ions Centre (AARC) at Place de Ville, Ottawa, Ontario K1A 0N8 , or 1-800-305-2059 , or www.tc.gc.ca/civilaviation/communications/centre/ addr ess.asp 2 4-0022 ( 01-2005 ) 1/2 No

. CF-2012-29 Issue Date 22 November 2012

Number: CF-2012-29 Subject: AC Generator Mounting Plate Corrosion
Effective: 7 December 2012 Applicability: Bombardier Inc. DHC-8 aeroplane models 102, 103, 106, 201, 202, 301, 311, 314 and 315, serial numbers 019 through 672. Compliance: As indicated below, unless already accomplished. Background: An incident has been reported on the DHC-8 aeroplane of a pilot commanded in-flight engine shut down in response to a engine low oil pressure warning indication. Further investigation revealed the mounti ng studs in the engine mounted AC generator mounting plate were pulled out of positi on and the threaded interface in the plate corroded. This resulted in a gap between t he AC generator and the generator mounting plate, leading to the loss of engine oil and the ensuing illumination of the associated engine low oil pressure warning indication. To ensure the integrity of the affected units, Part I of this AD mandates an inspection of the affected AC generator mounti ng adapters part numbers (P/N) 31708–500 or 31708-501, and, as applicable, replacement wi th new or serviceable mounting plates.
Part II of this AD mandates the incor poration of a repeat Maintenance Review Board (MRB) inspection applicable to the r eplacement of the AC generator mounting adapters P/Ns 31708-510 or 31708-511 only.
Corrective Actions: Part I – Inspection / Rectification - Applicable to aeroplane equipped with the AC Generator Mounting Adapter Kit P/Ns 31708–500 or 31708–501.
A. Within 6000 hours air time, or 3 years, or when the AC generator is removed for service, whichever occurs first, from t he effective date of this AD, perform an inspection of the affected AC generat or mounting adapters, and replace as applicable with serviceable mounting adapters P/Ns 31708-510 or 31708-511, or serviceable mounting adapters P/Ns 31708–500 or 31708–501, in accordance with Bombardier Service Bulletin 8-24-88 dated 13 December 2011 or later revisions approved by Chief, Continuing Airworthiness, Transport Canada.
B. For in-service mounting adapter s P/Ns 31708-500 or 31708-501, repeat the inspections in Part I A. of this AD ever y 6000 hours air time, or 3 years, or when the AC generator is removed for main tenance, whichever occurs first.No. N ° CF-2012-29 2/2

C. For aeroplanes with AC generator mounting adapters P/Ns 31708-500 or 31708-501 older than 10 years from date of manufactu re, within 1 year, or 2000 hours air time, or when the AC generator is removed for serv ice, whichever occurs first, replace with the new AC generators mounting adapter kit P/Ns 31708-510 or 31708-511. Part II – Amendment to the Maintenance Schedule - Applicable to aeroplanes equipped with the AC Generator Mounting Adapter Kit P/Ns 31708–510 or 31708-511. Within 30 days from the effective date of th is AD, incorporate MRB task 2420/14 into the approved scheduled maintenance program for t he applicable aeroplane, as detailed in the applicable Temporary Revisions (TR) of the DHC-8 Maintenance Program Manual specified below: DHC-8 Series PSM No. TR Number 100 1-8-7 MRB-153 200 1-82-7 MRB 2-31 300 1-83-7 MRB 3-162

Authorization: For the Minister of Transport, Infrastructure and Communities, 

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