Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to supersede an existing airworthiness directive (AD) for Sikorsky Aircraft Corporation (Sikorsky) Model S-64E helicopters. The existing AD requires checks of the main rotor blades for a crack. This proposed AD would retain the actions of the existing AD, would reflect that the type certificate (TC) for this model helicopter has been transferred to Erickson Air-Crane Incorporated (Erickson), and expand the applicability to include the similar Erickson Model S-64F helicopters. This proposed AD is prompted by a need to expand the applicability to include Model S-64F helicopters and clarify the applicable main rotor blades by part number. The proposed actions are intended to detect a crack in the main rotor blade and prevent blade separation and subsequent loss of control of the helicopter.