Airworthiness Directives; Airbus Helicopters Deutschland GmbH Helicopters

The FAA is adopting a new airworthiness directive (AD) for certain Airbus Helicopters Deutschland GmbH (AHD) Model MBB-BK 117 D-3 helicopters. This AD is prompted by reports of momentary direct current (DC) power interruption in flight of both essential busses. This AD requires revising the existing rotorcraft flight manual (RFM) to incorporate an emergency and malfunction procedure. The FAA is issuing this AD to address the unsafe condition on these products.