Summary
We propose to adopt a new airworthiness directive (AD) for certain Eurocopter France (Eurocopter) Model AS332C, AS332L, AS332L1, AS332L2, and EC225LP helicopters to require inspecting for the presence of blind holes in the tail gearbox (TGB) attachment fittings, and, if they are missing, installing an additional washer under the head of the attachment bolt until the attachment fitting is replaced with an airworthy attachment fitting. This proposed AD was prompted by the discovery of interference between the TGB aft attachment bolt and the structure fitting, caused by a manufacturing anomaly that omitted the blind hole required for proper fit of the attachment bolt. This condition, if not detected and corrected, could result in insufficient tightening of the TGB casing, damage to the TGB attachment, cracking under the attachment bolt, and loss of the TGB, resulting in loss of control of the helicopter.