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.