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) 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 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), 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-2008-17R1

Issue Date 

26 May 2008 

Number: CF-2008-17R1 

Subject: Tension-Torsion Straps (TTS) Failure 

Effective: 3 June 2008 

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

Cancellation: Cancels Airworthiness Directive (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 recalculation changed the retirement time in Chapter 4 of 

Maintenance Manual. 

As a result of this change, the TTS in service are to be replaced or inspected as a 

precautionary measure, pending already accumulated 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 the 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 later than 13 June 2008, verify the following: 

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

b. Number of flight hours since 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 applicable 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 replacement as a result of the above verification 

and inspection. Follow instruction provided in paragraphs 1.D.1. through 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 (renumber) 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 technical 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, Infrastructure 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.ca or any Transport Canada Centre