Pacific incident was longest ever single-engine diversion

A United Airlines Boeing 777-200ER was forced to fly a 190min diversion on one engine over the Pacific Ocean when it had been dispatched on a 180min limitation, according to the US Federal Aviation Administration. Boeing confirms that this is the longest ever single-engine diversion under extended-range twin-engine operations (ETOPS) rules.

The aircraft was operating Flight 842 from Auckland, New Zealand, to Los Angeles, USA, on 17 March when the captain was forced to shut down the No 2 Pratt & Whitney PW4090 engine because the oil pressure dropped dramatically, says the airline.

The aircraft was immediately cleared for diversion to Kona in the Hawaiian archipelago where it landed safely after a flight that United describes as "textbook". Early indications are that the engine may have suffered a bearing failure. United says the single-engine flying time was "just over 3h", but the FAA says it was "190 to 193min".

According to sources at the airline, the maximum FAA-approved concessionary one-engine flying time from suitable diversion airfields for a long-range United 777 is 207min, but this is only for exceptional circumstances.

Technically, the 777 is in a category of specially equipped long-range twins that are cleared under a standard ETOPS maximum of 180min, but in May 2000 the FAA approved United's 777s for a 15% increase to 207min under special circumstances. The airline normally, however, dispatches the aircraft on the basis of operational flight planning that assumes a 180min clearance, and this was what it did on 17 March, it confirms.

The FAA at present is working in co-operation with US industry body the Aviation Rulemaking Advisory Committee to draw up a new set of standards for long-range aircraft regardless of the number of engines they have, possibly taking modern twins into the 240min ETOPS range and beyond.

Europe's Joint Aviation Authorities, also working towards new standards for long-range flights over oceanic or wilderness areas, so far finds itself very much at odds with the US proposals (Flight International, 31 December-6 January).

Source: Flight International