The US Federal Aviation Administration should review the design of the first stage high-pressure turbine disc on General Electric CF6-80C2 turbofans, the National Transportation Safety Board has recommended.

Specific recommendations include "establishing hard time inspection intervals and modifying repair procedures". The Board cites an accident involving a US Airways Boeing 767 and incidents involving Thai Airways and Gulf Air aircraft. In the US Airways event, a disc section penetrated the forward wing spar, passed through a fuel tank and the top of the wing before flying over the fuselage.

Meanwhile, preliminary checks by Pratt & Whitney have not produced indications why five PW4000-powered Airbus A330s suffered cracking in the nuts of some engine mount bolts. Malaysia Airlines and Korean Air detected the cracked nuts on the engine mount aft barrel bolts. Airbus issued an alert which was followed by an order from the aircraft's certification body, the French DGAC, to inspect all French-registered PW4000 powered aircraft.

Source: Flight International