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 ma y 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 Can ada, Ottawa, telephone 613 952-4357.
URGENT URGENT URGENT URGENT URGENT URGENT URGENT URGENT URGENT



### TRANSPORT CANADA EMERGENCY AIRWORTHINESS DIRECTIVE PLEASE FORWARD IMMEDIATELY TO THE PERSON RESPONSIBLE FOR THE OPERATION AND MAINTENANCE OF YOUR AIRCRAFT

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

2 4-0022 ( 01-2005 ) 1/2 No

. CF-2012-08
Issue Date 30 January 2012

Number: CF-2012-08

Subject: Power Lever Friction Brake Assembly Discrepancy

Effective: 30 January 2012

Applicability: Bombardier Inc. DHC-8 Aeropl ane Models 102, 103, 106, Serial Numbers 003 through 039

Compliance: As indicated below, unless already accomplished.

Background: During maintenance, it was discovered that it was possible to inadvertently move the power levers through the flight idle gate in to the beta range. An investigation revealed that an un-chamfered leaf spring in the fric tion brake may contact the power lever latch when the friction adjusting knob is fully loosened. This can result in the lifting of the power lever latch and allow the power levers to pass through the flight idle gate without lifting the triggers.

Further investigation also determined that an un-chamfered spring installation with a pre-Service Bulletin (SB) 8-76-2 (Mod 8/0443) friction brake nut can further increase the possibility of allowing power levers to pass th rough the flight idle gate without lifting the triggers, when the friction adjus ting knob is fully loosened.

The above discrepancies, if not corrected, ma y result in an unsafe condition where both engines can inadvertently be operat ed in beta mode during flight.

In order to address this potentially uns afe condition, Bombardier has issued:

• Alert Service Bulletin (ASB) A8-76-32 r equiring operators to inspect the springs and chamfer the springs as applicable, and

• SB 8-76-02 Rev. A to replace the pre-SB 8-76-2 (Mod 8/0443) original friction brake nut with a new friction brake nut with larger shoulders.

This Airworthiness Directive (AD) is being issued to mandate compliance with Bombardier ASB A8-76-32 and SB 8-76-02 Rev. A requirements on the affected aeroplanes.No. N ° CF-2012-08 2/2

Corrective Actions: Part I

Within 50 flight hours or 10 days, whichever o ccurs first, from the effective date of this AD, perform an inspection of the friction leaf spring assembly and rework as applicable, in accordance with Bombardier ASB A8-76-32, dated January 27 2012, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.

Part II

Within 50 flight hours or 10 days, whichever o ccurs first, from the effective date of this AD, install a new friction brake nut, in a ccordance with Bombardier SB 8-76-02 Rev. A, dated January 25 2012, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.

Compliance with the initial issue of SB 8-76-2 (Mod 8/0443), dated January 24 1986, meets the intent of Part II of this AD.

Authorization: For the Minister of Transport, Infrastructure and Communities



### ORIGINAL SIGNED BY
Derek Ferguson Chief, Continuing Airworthiness

Contact: Mr. A K Durrani, Continuing Airworthine ss, Ottawa, telephone 613-952-4357, facsimile 613-996-9178 or e-mail CAWWEBFeedback@tc.gc.ca or any Transport Canada Centre.