Airworthiness Directives; Airbus Helicopters

We are publishing a new airworthiness directive (AD) for Airbus Helicopters Model AS350B3 helicopters. This AD was sent previously to all known U.S. owners and operators of these helicopters and supersedes Emergency AD 2015-22-52, dated October 28, 2015. This AD requires revising the rotorcraft flight manual (RFM) to stop performing the yaw load compensator check during preflight procedures and instead perform it during post-flight procedures after rotor shut-down. This AD also requires the yaw servo hydraulic switch to be in the "ON" position before taking off. This AD is prompted by two accidents and one incident of Airbus Helicopters Model AS350B3 helicopters. From preliminary investigations, loss of tail rotor (T/R) control during takeoff was evident in each event. These actions are intended to prevent takeoff without hydraulic pressure in the T/R hydraulic system, loss of T/R flight control, and subsequent loss of control of the helicopter.