Document ID: chunk:federal_register_of_legislation:F2009L00283:body:0:p3
Version: federal_register_of_legislation:F2009L00283
Segment Type: other
Provision Reference: 
Character Range: 5538–7074

was found that the lock-wiring hole was missing from the screw head, making it impossible to ensure additional security using lock-wiring between the screw head and the nut.

             Failure of the clamp attachment screw can lead to damage to the main or tail rotor blades, and is a risk for persons on the ground.

             Amendment 1included a change to the applicability section to include those attachment screws that are welded to the barrel, and to cover the absence of a part number on some clamps.

             More recently, a new case of failure of the clamp attachment screw has been reported after having complied with the instructions in a previous amendment of this AD and the lock-wire which is intended to secure the attachment screw, retained the clamp until the screw failure was discovered.  Later examinations showed this failure was caused by non-conformity of the hardness of the affected screw.

             This amendment requires the installation of a supplementary lock-wire to ensure the clamp is retained pending replacement of the screw or the screw hardness condition has been verified to be correct.

             Pending corrective action on the screw, this AD also requires repetitively inspecting the integrity of the affected screws and retaining clamps.

             The original issue of this AD became effective 25 June 2008.

             Amendment 1 of this AD became effective on 29 August 2008.

James Coyne
Delegate of the Civil Aviation Safety Authority

3 February 2009