A Rolls-Royce Trent 700-powered Airbus A330 experienced fuel flow blockage to both engines recently, leading Airbus and EASA to issue precautionary instructions to prevent similar incidents. The prime suspect: a fuel system icing condition similar to the one that led to the January 2008 crash
of a Trent 800-powered British Airways 777 at London Heathrow.
The Airbus warning came via an All-Operators Telex Wednesday. EASA followed up with an emergency airworthiness directive
From the directive:
During a recent in-service event the flight crew of a Trent 700 powered A330 aircraft reported a temporary Engine Pressure Ratio (EPR) shortfall on engine 2 during the take-off phase of the flight. The ENG STALL warning was set. The flight crew followed the standard procedures which included reducing throttle to idle. The engine recovered and provided the demanded thrust level for the remainder of the flight. Data analysis confirmed a temporary fuel flow restriction and subsequent recovery, and indicated that also engine 1 experienced a temporary fuel flow restriction shortly after the initial event on engine 2, again followed by a full recovery. The engine 1 EPR shortfall was insufficient to trigger any associated warning and was only noted through analysis of the flight data. No flight crew action was necessary to recover normal performance on this engine. The remainder of the flight was uneventful.
EASA stressed that "[w]hile no direct fuel system fault has been identified," ice build-up in the water scavenge system "cannot be excluded as a contributing factor," and testing continues.
Operators of affected aircraft must deactivate the Standby Fuel Pump Scavenge System and are prohibited from dispatching planes with one main fuel pump inoperative.