Document ID: chunk:federal_register_of_legislation:F2006B04571:body:0:p2
Version: federal_register_of_legislation:F2006B04571
Segment Type: other
Provision Reference: 
Character Range: 3558–5003

from metal fatigue.

            Amendment 22 is issued in response to a new FAA AD which was prompted by a report of another cracked main rotor mast. Metallurgical inspection revealed that the mast cracked as a result of fatigue in snap ring groove radii that were smaller than the
            0.020 inch minimum allowable dimension. The FAA has concluded that several corrections to the RIN counting procedure are required based on a review of the fatigue data and previously issued Directives.

            Amendment 21 added Requirement 2, developed by Bell and the FAA to better control fatigue in the main rotor mast and trunnion following a fatigue-related accident. Requirement 1 was reformatted slightly, without technical change and became effective on 28 April 2000.

            Amendment 20, which updated the amendment status of the Bell 212 Maintenance Manual, became effective on 25 February 1999.

            Amendment 19, which introduced the Retirement Index Number limitation for the main rotor mast and trunnion, became effective on 11 September 1997.

            Amendment 18 of this Airworthiness Directive became effective on 5 September 1991.

            The original issue of this Airworthiness Directive became effective on 31 December 1975.

 David Alan Villiers
 Delegate of the Civil Aviation Safety Authority

 8 August 2000

 The above AD is notified in the Commonwealth of Australia Gazette on 9 August 2000.