Airworthiness Directives; Airbus Helicopters Deutschland GmbH (Previously Eurocopter Deutschland GmbH) Helicopters

We are adopting a new airworthiness directive (AD) for Airbus Helicopters Deutschland GmbH (AHD) (previously Eurocopter Deutschland GmbH) Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2, C-1, and C-2 helicopters. This AD requires an initial and recurring inspection of the N2 control arm and, depending on the outcome of the inspection, repairing or replacing the N2 control arm. This AD was prompted by a report of a heavily corroded and broken N2 control arm. The actions of this AD are intended to detect corrosion, a crack, or a scratch in the N2 control arm, which could lead to failure of the N2 control arm, a drop in rotor speed, and subsequent loss of control of the helicopter.