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-2012-15

Issue Date 

 30 April 2012 

Number: CF-2012-15 

Subject: Chafing of the Nacelle Fire Detection Wire on the Main Landing Gear Yoke 

Effective: 14 May 2012 

Applicability: Bombardier Inc. DHC-8 aeroplane models 400, 401 and 402, serial numbers 4001 

through 4382.

Compliance: As indicated below, unless already accomplished. 

Background: There have been two (2) in-service reports of chafing found on the main landing gear

(MLG) yoke. The chafing was attributed to contact between the nacelle fire detection wire 

and the MLG yoke. This chafing may lead to cracking and subsequent failure of the MLG 

yoke. 

Failure of the MLG yoke could adversely affect the safe landing of the aeroplane. In 

addition, failure of the fire detection wire could prevent the detection of a fire in the 

nacelle assembly. 

This AD mandates the inspection of the nacelle fire detection wires and MLG yoke for 

damage and the installation of new brackets to secure the fire detection wire to prevent 

chafing against the MLG yoke. 

Corrective 

Actions: 

Within 6000 hours air time or 36 months, whichever occurs first, from the effective date of 

this AD, perform the following: 

A. Perform a detailed visual inspection (DVI) of the left and right nacelle fire detection 

wire in accordance with the Accomplishment Instructions in Bombardier Service 

Bulletin (SB) 84-26-11, Revision A, dated 25 January 2012, or later revisions 

approved by the Chief, Continuing Airworthiness, Transport Canada. 

1. If any damage is found on a fire detection wire, before further flight, remove and 

replace it with a new fire detection wire, both in accordance with the 

Accomplishment Instructions in the above-mentioned SB. Proceed to paragraph 

B of this AD. 

2. If no damage is found, proceed to paragraph B of this AD. 

B. Perform a DVI of the MLG yoke in accordance with the Accomplishment Instructions 

in the above-mentioned SB. 

1. If no damage is found on the MLG yoke, proceed to paragraph C of this AD. 
No.

N° CF-2012-15 2/2 

2. If the damage found on the MLG yoke is within the limitations specified in 

Figure 8, of the above-mentioned SB, before further flight, repair the damaged 

area in accordance with the Accomplishment Instructions in Figure 9, Steps 1-10, 

of the above-mentioned SB. Proceed to paragraph C of this AD. 

3. If the damage found on the MLG yoke exceeds the limitations specified in 

Figure 8, of the above-mentioned SB, before further flight, contact the 

Bombardier Q Series Help Desk for approved repair instructions. The approved 

repair must specifically reference this AD. Proceed to paragraph C of this AD. 

C. Install the new nacelle brackets and associated hardware, in accordance with the 

Accomplishment Instructions in the above-mentioned SB. 

Authorization: For the Minister of Transport, Infrastructure and Communities 

ORIGINAL SIGNED BY

Derek Ferguson 

Chief, Continuing Airworthiness 

Contact: Mr. Robert Farinas, Continuing Airworthiness, Ottawa, telephone 613-952-4357, 

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