Summary
This document proposes revising an existing airworthiness directive (AD) for Kaman Aerospace Corporation (Kaman) Model K-1200 helicopters. That AD currently requires reducing the life limit of the rotor shaft and teeter pin assembly and establishing a life limit for the flap clevis. This action would retain those requirements but would remove a flap clevis part number from the applicability. This proposal is prompted by the determination after an analysis of testing results that a certain flap clevis should have an unlimited life. The actions specified by the proposed AD are intended to remove the life limit for a specified flap clevis and to revise the maintenance manual by removing the life limit for that flap clevis. Also, the actions specified by the proposed AD are intended to prevent fatigue failure of the rotor shaft, the teeter pin assembly, and the flap clevis and subsequent loss of control of the helicopter.