AD FAA-2011-1038

We are adopting a new airworthiness directive (AD) for Pratt & Whitney Canada PT6A-15AG, -27, -28, -34, -34AG, -34B, and -36 series turboprop engines. This emergency AD was sent previously to all known U.S. owners and operators of these engines. This AD requires the removal of affected part manufacturer approval (PMA) replacement Timken Alcor Aerospace Technologies, Inc. (TAATI) first stage reduction sun gears and the interacting planet gears, from the propeller reduction gearbox assembly. This AD was prompted by failures of certain PMA replacement first stage reduction sun gears, manufactured by TAATI. We are issuing this AD to correct the unsafe condition on these products.