Operators of Boeing 777-300ERs are being ordered urgently to remove another batch of interstage seals from General Electric GE90 engines, following an uncontained failure last October.

The failure involved a Thai Airways International 777-300ER which had been preparing to depart Bangkok for Zurich.

While the US FAA has already issued an emergency directive requiring removal of certain interstage seals on GE90s, it has followed with another emergency order expanding the serial numbers of the seals involved.

The latest directive – adding another 16 serial numbers to the previous eight – is effective immediately and orders removal of the seals within five cycles.

Thai Airways’ flight TG970 had commenced its take-off roll on 20 October when it suffered an uncontained high-pressure turbine failure in the left-hand powerplant, resulting in debris penetrating the fuselage and the aircraft’s other engine.