Document ID: chunk:federal_register_of_legislation:F2008L04478:body:0:p2
Version: federal_register_of_legislation:F2008L04478
Segment Type: other
Provision Reference: 
Character Range: 2863–5498

and 2.B.3. of EUROCOPTER EC 120 ASB No. 76A005 Revision 1.

                3. Do not install on a helicopter twist grip assemblies listed below not having accomplished EUROCOPTER EC120 SB No. 76-005 Revision 1, unless the correct bonding strength of the control pinion on the pilot and co-pilot collective lever drive tubes has been checked in accordance with paragraph 2.B.4 of EUROCOPTER EC 120 ASB No. 76A006 Revision 2.

                P/N C761A2024102 and C761A2024103 and C761A2024104 with S/N below 418; or

                P/N C761A2025102 and C761A2025103 and C761A2025104 with S/N below 382.

             The use of later approved revisions of these documents is acceptable for compliance with the requirements of this AD.

             Note:  EASA AD 2008-0185 dated 8 October 2008 refers. This AD supersedes EASA AD 2006-0253.
Compliance:  For Requirement 1 - Within 9 months after the effective date of this AD, unless previously accomplished.

             For Requirement 2.a. - Within 110 flight hours or 9 months after the effective date of this AD, whichever occurs first, unless previously accomplished.

             For Requirement 2.b. - Pending replacement of the twist grip drive tube as per Requirement 2.a. of this AD.

             For Requirement 2.c. - From the effective date of this AD.

             For Requirement 3 - From the effective date of this AD.
             This Amendment becomes effective on 18 December 2008.
Background:  This Airworthiness Directive is in response to a twist grip failure experienced during an autorotation training procedure during which the engine remained at idle rating although the twist grip had been turned back to the flight position.  Analysis has revealed failure of the twist grip drive tube and control pinion bonded attachment due to non-compliant preparation of the bonding surfaces on the two components.

             Further investigation has revealed other twist grip batches potentially affected by non appropriate surface preparation prior to bonding.

   Over time, such surface preparation creates a risk of failure of the bonded attachment of the drive tube and thus a risk of losing in flight the engine fuel flow control function, which may constitute an unsafe condition.

   This amendment ensures that the twist grips correct bonding strength of the control pinion on the pilot and co-pilot collective lever drive tubes is achieved in accordance with the latest approved data.

   The original issue of this AD became effective on 26 October 2006.

James Coyne
Delegate of the Civil Aviation Safety Authority

6 November 2008