Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters

الملخص

We are adopting a new airworthiness directive (AD) for Sikorsky Aircraft Corporation (Sikorsky) Model S-76A helicopters to require modifying the electric rotor brake (ERB) and inserting changes into the "Normal Procedures" and "Emergency Procedures" sections of the Rotorcraft Flight Manual (RFM). This AD was prompted by a fire in the main gearbox area as a result of a hot electric rotor brake (ERB). The actions are intended to prevent overheating of the ERB, ignition of the ERB hydraulic fluid, a fire in the main gearbox area, and subsequent loss of control of the helicopter.