Transport Transports 

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 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-2010-28R1

Issue Date 

12 June 2012 

Number: CF-2010-28R1 

Subject: Elevator Power Control Unit – Shaft (Tailstock) Swaged Bearing Wear

Effective: 25 June 2012 

Revision: Supersedes Airworthiness Directive CF-2010-28 

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

through 4334, and 4336. 

Compliance: As indicated below, unless already accomplished. 

Background: Several reports have been received on the elevator power control units (PCUs) where 

the shaft (tailstock) swaged bearing liners had shown a higher than normal rate of wear. 

Investigation revealed that the excessive wear was due to the paint contamination 

between the bearing roller and bearing liner. The bearing paint contamination is known to 

be abrasive and could seize the bearing. 

This condition, if not corrected, could lead to excessive airframe vibrations and difficulties 

in aircraft pitch control. 

This AD mandates a free-play check of the shaft swaged bearing installed in the elevator 

PCU tailstock end and replacement of the shaft swaged bearings if excessive free-play is 

found. 

This AD is revised to amend the applicability for DHC-8 Series 400 aeroplanes. 

Corrective 

Actions: 

A. Perform a free-play check of the shaft swaged bearing, part number (P/N) 

MS14103-7, installed in the tailstock end of each elevator PCU (three PCUs per 

elevator surface), P/Ns 390600-1007 and 390600-1009, in accordance with 

paragraph 3.B, Part A of Bombardier Aerospace Service Bulletin (SB) 84-27-52, 

Original Issue, dated 25 May 2010, or later revisions approved by the Chief, 

Continuing Airworthiness, Transport Canada, with the following schedule: 

1. For aeroplanes that have accumulated 8000 hours air time or more, within 2000 

hours air time from the original effective date of this AD (8 September 2010); 

2. For aeroplanes that have accumulated less than 8000 hours air time, within 6000 

hours air time, but not to exceed 10 000 total hours air time, from the original 

effective date of this AD (8 September 2010). 
No.

N° CF-2010-28R1 2/2 

B. If the bearing free-play is within the limits specified in the above-mentioned SB, no 

further action is required. 

C. If the bearing free-play exceeds the limits specified in the above-mentioned SB, 

replace the elevator PCU with a serviceable one before further flight in accordance 

with paragraph 3.B, Part B of Bombardier Aerospace SB 84-27-52, Original Issue, 

dated 25 May 2010, or later revisions approved by the Chief, Continuing 

Airworthiness, Transport Canada. 

Authorization: For the Minister of Transport, Infrastructure and Communities 

ORIGINAL SIGNED BY

Derek Ferguson 

Chief, Continuing Airworthiness 

Contact: Mr. Gordanko Jeremic, Continuing Airworthiness, Ottawa, telephone 613-952-4357, 

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