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) 593 . 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 invalidat e 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), Aircraft Certification Branch, Transport Canada, Otta wa, 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 Communica tions 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-2008-17R1

Issue Date 26 May 2008

Number: CF-2008-17R1

Subject: Tension-Torsion Straps (TTS) Failure

Effective: 3 June 2008

Revision: Supersedes Airworthiness Directiv e (AD) CF-2008-17 dated 9 May 2008.

Cancellation: Cancels Airworthiness Dire ctive (AD) CF-99-24R1.

Applicability: Eurocopter Canada Ltd. (formerly MBB Canada Ltd.) Model BO 105 LS-A3 helicopters. Compliance: As indicated unless already accomplished.

Background: The tension-torsion strap (TTS) failure on a MBB BK 117 helicopter in July 1999, initiated a

TTS service life recalculation. This recalculat ion changed the retirement time in Chapter 4 of

Maintenance Manual.

A s a result of this change, the TTS in serv ice are to be replaced or inspected as a precautionary measure, pending already accumu lated service hours and the calendar time

since their last installation.

Eurocopter Canada Alert Service Bulletin (ASB) – BO 105 LS-10-10 Revision 1, dated 8 January 2008, or later revision approved by t he Chief, Continuing Airworthiness provides

instructions for time-in-service calculation and inspection criteria for part evaluation.

Corrective

Actions: 1. Service life Verification

Within the next 25 air time hours, but no la ter than 13 June 2008, verify the following:

a. The time accumulated since last part installation (years);

b. Number of flight hours si nce last installation; and

c. Number of flights since last installation, in accordance with section 1.D. of the ASB.

2. New Service life Limitation

Based on verification results above, as soon as practicable, but no later than 17 June 2008,

establish the new service life limitation and inspection schedule for those parts that are qualified for, in accordance with applicabl e paragraphs of section 1.D. of the ASB.

3. Inspection

Within the next 50 air time hours inspect all parts for damage in accordance with section

2.B.2. of the ASB.No.

N ° CF-2008-17R1 2/2

4. Parts Replacement

Replace those parts that were identified for r eplacement as a result of the above verification and inspection. Follow instruction provided in paragraphs 1.D.1. thr ough 1.D.5. and 2.B.1. through 2.B.2. of the ASB. Scrap replaced parts.

5. Part Re-Identification

Within the next 50 air time hours re-identify (renum ber) those parts that are eligible for (as per sections 1.D. 6 and 1.D. 7.) including main rotor heads, in accordance with paragraph

2.B.1.2. of the ASB.

6. Documentation

Enter into the historical records the technica l data related to corrective actions, as required by the paragraphs 2.B1.3. and 2.B.1.4. of the ASB.

Authorization: For Minister of Transport, In frastructure and Communities

Derek Ferguson Acting Chief, Continuing Airworthiness

Contact: Mr. Bogdan Gajewski, Continuing Airworthiness, Ottawa, telephone 613-952-4450, facsimile 613-996-9178 or e-mail: gajewsb@tc.gc.c a or any Transport Canada Centre