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 na me. 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 b y the Continuin g Airworthiness Division ( AARDG ) , National Aircraft Certification Branch, Trans p ort Canada, Ottawa, tele p hone 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 Communicat ions 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
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. CF-2011-29 Issue Date 2 August 2011



### Number: CF-2011-29 Subject: Hydraulic Accumulators – Screw Cap/End Cap Failure
Effective: 18 August 2011 Applicability: Bombardier Inc. DHC-8 Aeroplane, Series 100, 200 and 300, Serial Numbers, 003 and subsequent Compliance: As indicated, unless already accomplished. Background: Seven cases of on-ground hydraulic accumulator screw cap or end cap failure have been experienced on CL-600-2B19 (CRJ) aeroplanes, resulting in loss of the associated hydraulic system and high-energy impact damage to adjacent systems and structure. To date, the lowest number of flight cycles accumulated at the time of failure has been 6991. Although there have been no failures to date on any DHC-8 aeroplanes, similar accumulators to those installed on the CL-600-2B19, Part Numbers (P/N) 0860162001 and 0860162002 (Parking Brake Accumulator), are installed on the aeroplanes listed in the Applicability section of this directive.
A detailed analysis of the systems and structure in the potential line of trajectory of a failed screw cap/end cap for the accumulator has been conducted. It has identified that the worst-case scenarios would be the loss of number 2 hydraulic system, and damage to aeroplane structures. This directive gives instructions to determine the part number and serial number of the existing parking brake accumulator, and where applicable, replace the accumulator.
Corrective Actions: Part I - Replacement of Parking Brake Accumulator Within 2000 hours air time or 12 months, after the effective date of this directive, whichever comes first:
A. Determine the part number and serial number of the parking brake accumulator in accordance with the Accomplishment Instructions of Bombardier Service Bulletin (SB) 8-32-170, dated 25 February 2011, or later revision approved by the Chief, Continuing Airworthiness, Transport Canada.
B. For accumulators that do not have P/N 0860162001 or 0860162002, no further action is required.No. N ° CF-2011-29 2/2



### C. For accumulator with P/N 0860162001 or 0860162002:
1. If the serial number is listed in the Table of paragraph 3.B.(2) of the above-mentioned SB, no further action is required.
2. If the serial number is not listed in the Table paragraph 3.B.(2) of the above-mentioned SB, replace the accumulator in accordance with the Accomplishment Instructions of the above-mentioned SB, or if applicable, Bombardier SB 8-32-172, dated 15 March 2011, or later revision approved by the Chief, Continuing Airworthiness, Transport Canada. Part II - Spare Parts
A s of the effective date of this directive, no replacement/spare accumulator with P/N 0860162001 or 0860162002 is permitted to be installed on any aeroplane unless its serial number is listed in paragraph 3.B.(2) of Bombardier SB 8-132- 170, dated 25 February 2011, or later revision approved by the Chief, Continuing Airworthiness, Transport Canada.
Authorization: For the Minister of Transport, Infrastructure and Communities
ORIGINAL SIGNED BY Anthony Wan Acting 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.