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-2010-08

Issue Date 

16 March 2010 

Number: CF-2010-08 

Subject: Electrical Power — AC Wiring Harness Chafing on Centre Wing Lower Flap Shroud

Effective: 29 March 2010 

Applicability: Bombardier Inc. DHC-8 Aeroplane, Models 400, 401 and 402, Serial Numbers 4001 

through 4169 

Compliance: As indicated below unless already accomplished. 

Background: Operators of DHC-8 400 Series aeroplanes have been reporting chafing of wires in the 

AC wire harnesses located along the lower wing shroud on either wing resulting in a loss 

of various system services. Chafed wires may lead to arcing, local overheating and AC 

generator failure. The AC generators provide power to the anti-icing heaters, including 

pitot / static heater, engine adapter heater, and propeller heater. Failure of both AC 

generators would result in the loss of these systems and poses a safety concern. 

Investigation has revealed that at four wiring harness tie down mount locations, the blind 

fasteners used to attach the tie down mount base were found to have protruding stems 

which chafed through the wire insulation leading to arcing damage. In addition, the wire 

chafing along the wing rear spar lower shroud has been attributed to sagging wire 

bundles resting on the structure and insufficient support in low clearance areas. 

This directive mandates the replacement of the blind fasteners with solid rivets, and to 

inspect for and rectify damaged wiring along the wing lower shroud. 

Corrective 

Actions: 

A. Inspection at Four Wiring Harness Tie Down Mount Locations and 

Replacement of Blind Fasteners 

Within 200 hours air time after the effective date of this directive, replace the blind 

fasteners installed at the four wiring harness tie down mount locations and perform 

inspection, and rectification as required, in accordance with paragraph B(6) of the 

Accomplishment Instructions in Bombardier Inc. Service Bulleting (SB) A84-24-44, 

Revision A, dated 02 February 2010, or later revision approved by the Chief, Continuing 

Airworthiness, Transport Canada. 

NOTE: Previous modification, inspection, and rectification as required, in accordance with 

the Accomplishment Instructions in Bombardier Inc. SB A84-24-44, dated 

27 January 2010, or incorporation of Bombardier Inc. Modsum Number 

IS4Q5700013, satisfies the requirement of section A of this directive. 
No.

 N° CF-2010-08 2/2 

B. Visual Inspection of AC Feeder Cables along Lower Wing Shroud 

In accordance with the following schedule: 

1. For aeroplanes with AC feeder cables not covered with protective Teflon tubing 

(Modsum Number IS4Q2450001 or production Modsum 4Q109946 not 

incorporated): 

Within 600 hours air time after the effective date of this directive. 

2. For aeroplanes with AC feeder cables covered with protective Teflon tubing 

(Modsum Number IS4Q2450001 or production Modsum 4Q109946 

incorporated): 

Within 4000 hours air time after the effective date of this directive. 

Inspect wiring harness installation along the wing rear spar lower shroud and perform all 

rectification in accordance with the Accomplishment Instructions in Bombardier Inc. SB 

A84-24-44, Revision A, dated 02 February 2010, or later revision approved by the Chief, 

Continuing Airworthiness, Transport Canada. 

NOTE: Previous inspection and rectification in accordance with Bombardier Inc. 

SB A84-24-44, dated 27 January 2010, satisfies the requirement of section B of 

this directive. 

C. Reporting Requirement 

Within 14 days after the visual inspection of AC feeder cables, report all findings to 

Bombardier Technical Help Desk. 

Authorization: For Minister of Transport, Infrastructure and Communities 

ORIGINAL SIGNED BY 

Derek Ferguson 

Chief, Continuing Airworthiness 

Contact: Miss Helen Tsai, Continuing Airworthiness, Ottawa, telephone 613-952-4357, facsimile 

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