Document ID: chunk:federal_register_of_legislation:F2006B10758:body:0:p3
Version: federal_register_of_legislation:F2006B10758
Segment Type: other
Provision Reference: 
Character Range: 5458–6576

which a main rotor blade failed on a Model 369D helicopter due to cracks. The blade that failed had accumulated over 2,300 hours time in service. Subsequent investigation revealed cracks in two other blades on the same helicopter. The cracks had initiated in the lower inboard doubler and propagated in a chordwise direction through the blade skin and spar. These fatigue cracks may have been caused by residual stresses induced by non-conforming doublers that were used to construct the blade.

               Amendment 1 introduced new Requirement Documents, limited the affected blades to certain serial numbers, and reduced the inspection threshold time.

               Amendment 2 is issued in response to a new FAA AD which requires the same inspections required by the previous FAA AD, but deletes the Model 369, specifies recording torque events, and establishes a shorter retirement life for certain blades.

               Amendment 1 of this Airworthiness Directive became effective on 4 February 1998.

               The original issue of this Airworthiness Directive became effective on 8 January 1998.