Summary
We propose to adopt a new airworthiness directive (AD) for the specified Eurocopter model helicopters. This proposed AD would require an initial and recurring inspections of the inner angles and flanges of the 9-degree frame on the right-hand (RH) and left-hand (LH) sides for a crack. If a crack is found, this proposed AD would require, before further flight, repairing the frame. This proposed AD is prompted by the discovery of a crack in the 9-degree frame of a Eurocopter Model AS-365N2 helicopter. These cracks could also develop on the other specified model helicopters because they contain the same 9-degree frame. The actions specified by this proposed AD are intended to detect a crack in the 9-degree frame to prevent loss of structural integrity and subsequent loss of control of the helicopter.