Airworthiness Directives; MD Helicopters Inc. (MDHI) Helicopters

FAA / Federal Register · 2021-26332

The FAA is adopting a new airworthiness directive (AD) for certain MD Helicopters Inc. (MDHI), Model 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters. This AD was prompted by a report of a spiral crack in the pilot-to-copilot tail rotor torque tube (torque tube). This AD requires a one-time visual and recurring borescope inspections of the torque tube and depending on the results, removing the torque tube from service. The FAA is issuing this AD to address the unsafe condition on these products.