Summary
This document proposes adopting a new airworthiness directive (AD) for the MD Helicopters, Inc. Model 600N helicopters. The AD would require replacing the fuselage Station 75 control support bracket assembly (control support bracket), reducing the life limit, and revising the Limitations section of the applicable maintenance manual to state the reduced life limits on certain serial-numbered helicopters. This proposal is prompted by information received from the manufacturer indicating that the fatigue life of the control support bracket is shorter than the original analysis indicated. The actions specified by the proposed AD are intended to prevent failure of the control support bracket and subsequent loss of control of the helicopter.