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-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 mounting studs in the engine mounted AC generator 

mounting plate were pulled out of position and the threaded interface in the plate 

corroded. This resulted in a gap between the 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 mounting adapters part numbers (P/N) 31708–500 or 

31708-501, and, as applicable, replacement with new or serviceable mounting plates. 

Part II of this AD mandates the incorporation of a repeat Maintenance Review 

Board (MRB) inspection applicable to the replacement 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 the effective date of this AD, perform an

inspection of the affected AC generator 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 adapters P/Ns 31708-500 or 31708-501, repeat the 

inspections in Part I A. of this AD every 6000 hours air time, or 3 years, or when the 

AC generator is removed for maintenance, 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 manufacture, within 1 year, or 2000 hours air time,

or when the AC generator is removed for service, 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 this AD, incorporate MRB task 2420/14 into the 

approved scheduled maintenance program for the 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.