AD FAA-2011-0944

We are adopting a new airworthiness directive (AD) for all Pratt & Whitney PW4050, PW4052, PW4056, PW4060, PW4060A, PW4060C, PW4062, PW4062A, PW4152, PW4156, PW4156A, PW4158, PW4160, PW4460, PW4462, and PW4650 turbofan engines, including models with any dash number suffix. This AD was prompted by an engine overspeed event that occurred during taxi and resulted in a high-pressure compressor surge and tailpipe fire. This AD requires replacing Pratt & Whitney fuel metering units (FMUs), part numbers (P/Ns) 53T335 (HS 801000-1), 55T423 (HS 801000-2), and 50U150 (HS 801000-3) at the next shop visit after the effective date of this AD. We are issuing this AD to prevent engine overspeed on these engines, which could result in an uncontained engine failure and damage to the airplane.