Action
Final rule; request for comments.
Summary
We are adopting a new airworthiness directive (AD) for MD Helicopters, Inc. (MDHI), Model MD900 helicopters. This AD requires an eddy current inspection of the main rotor upper hub assembly (upper hub) for a crack and replacing the upper hub with an airworthy upper hub before further flight if there is a crack. This AD is prompted by a report of cracks on an upper hub at the blade attach holes. The actions specified by this AD are intended to detect a crack in the upper hub to prevent failure of the upper hub and subsequent loss of control of the helicopter.