Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters
We are adopting a new airworthiness directive (AD) for Sikorsky Aircraft Corporation Model S-76D helicopters. This AD requires revising the rotorcraft flight manual (RFM) to prohibit Barometric Altitude Hold (ALT) mode beyond a certain rate of climb or descent. This AD is prompted by a report of the autopilot being unable to maintain level flight during certain flight conditions. The actions specified by this AD are intended to prevent a significant pilot workload increase, pilot disorientation, and subsequent loss of control of the helicopter.