Aircraft
FAA Issues Emergency AD To Inspect PW4000-112 Fan Blades
The interim order by U.S. authorities to inspect all Pratt & Whitney PW4000-112s applies to some 125 Boeing 777s.

The FAA issued an emergency airworthiness directive Tuesday night requiring inspection of all fan blades from certain Pratt & Whitney PW4000 turbofans for cracking after investigators found signs of metal fatigue in the engine that failed in a United Airlines Boeing 777-200 on September 30. The interim action mandates that operators perform a thermal-acoustic imaging (TAI) inspection of the hollow titanium fan blades on each engine. TAI can detect cracks on the interior surfaces of the hollow fan blades or in areas that cannot be seen during a visual inspection.