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-2012-28R1

Issue Date 

 26 November 2012 

Number: CF-2012-28R1 

Subject: Main Landing Gear Door Actuator Scraper Incorrect Installation 

Effective: 12 December 2012 

Revision: Supersedes Airworthiness Directive CF-2012-28, dated 13 October 2012 

Applicability: Bombardier Inc. DHC-8 aeroplane models 400, 401 and 402, serial numbers (S/N) 

4001 and subsequent, equipped with Main Landing Gear (MLG) door actuators with 

part number (P/N) 46830-7 and serial numbers included in Section 1.A, Effectivity, 

of Bombardier Service Bulletin (SB) 84-32-108, Revision A, dated 01 October 2012. 

Compliance: As indicated below, unless already accomplished. 

Background: It was discovered that a batch of MLG door actuators, P/N 46830-7, may be assembled 

with the scraper installed backwards. This condition, if not corrected, could result in 

increased actuator friction, which could hinder operation of the MLG alternate extension 

system (AES). In the case of a failure of the primary MLG extension system, the failure of 

the MLG AES on one side will lead to an unsafe asymmetrical landing configuration. 

This AD mandates the repetitive functional check of the AES until replacement of the 

affected MLG door actuators. 

This revision is issued to correct the applicability section of the original issue of this AD. 

Corrective 

Actions: 

Part I - Repetitive Inspection 

Perform a functional check of the MLG AES in accordance with Part A of the 

Accomplishment Instructions of Bombardier SB 84-32-108, Revision A, dated 01 October

2012, or later revisions approved by the Chief, Continuing Airworthiness, Transport 

Canada, using the following schedule: 

A. Initially, as of the effective date of this AD: 

1. For MLG door actuators that have accumulated more than 950 hours air time, 

within 50 hours air time. 

2. For MLG door actuators that have accumulated 950 hours air time or less, before 

reaching 1000 hours air time. 

B. Subsequently, at intervals not to exceed 50 hours air time. 
No.

N° CF-2012-28R1 2/2 

Part II - Terminating Action 

Within 2000 hours air time or 12 months from the effective date of this AD, or before the 

MLG door actuator have accumulated 3000 hours air time, whichever occurs first,

replace all affected MLG door actuators P/N 46830-7 with MLG door actuators reworked

in accordance with Part B of the Accomplishment Instructions of Bombardier SB 84-32-

108, Revision A, dated 01 October 2012, or later revisions approved by the Chief, 

Continuing Airworthiness, Transport Canada, or with MLG door actuators P/N 46830-7 

with serial number not included in Section 1.A, Effectivity of the above-mentioned SB. 

For MLG door actuator P/N 46830-7 identified with Mod Status “32-106” on the 

identification plate, the requirements of Part II of this AD is met. 

Rework in accordance with Bombardier SB 84-32-108, Initial Issue, dated 

06 September 2012, also meets the requirements of Part II of this AD. 

Part III - Spare Affected 

As of the effective date of this AD, it is prohibited for anyone to install MLG door actuator 

P/N 46830-7 with S/N included in Section 1.A, Effectivity, of Bombardier SB 84-32-108,

Revision A, dated 01 October 2012, or later revisions approved by the Chief, Continuing 

Airworthiness, Transport Canada, unless it is identified with Mod Status “32-106” on the 

identification plate. 

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

ORIGINAL SIGNED BY

Derek Ferguson 

Chief, Continuing Airworthiness 

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

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