Summary
We propose to adopt a new airworthiness directive (AD) for Kaman Model K-1200 helicopters with certain main rotor blades (MRB) installed. This proposed AD would require inspecting each MRB for a crack or damage. This proposed AD is prompted by a report that a crack was found on an MRB during a tear-down inspection. The proposed actions are intended to detect a crack in the MRB, which could lead to failure of the MRB and subsequent loss of control of the helicopter.