By John Croft in Washington and David Learmount in London

European authority prepares to update rules but diversion time likely to depend on reliability of specific engines

Airbus has given a qualified welcome to the US Federal Aviation Administration's new regulation allowing suitably equipped twin-engined aircraft to fly as far as the operator wishes from usable diversion airports.

The FAA's air carrier operations branch manager Robert Reich says that the revised extended twin-engine operations (ETOPS) rule "has mechanisms for twins to go any length and any duration from an alternate airport, subject to the capabilities of the aircraft".

Airbus, whose four-engined A340 widebody family competes with Boeing's 777 twinjets, says the new rules "will enhance the flexibility of the extended-range operations of twin-engined aircraft like the A330, and at the same time they recognise quads maintain operational superiority on challenging routes over remote areas".

But the Toulouse-based manufacturer, which was represented along with the European Aviation Safety Agency on the FAA's Aviation Rulemaking Advisory Committee (ARAC), adds that it wants to take more time to study the fine detail of the 296-page document. The ARAC has been working on revising the ETOPS rule since 2000.

FAA officials say the increased flexibility will become increasingly important because flights over both polar regions will increase from 1,600 to 3,200 a day by 2010. When the ETOPS revisions take effect in February, Reich says, it will boost dispatch reliability for carriers faced with alternate airports along a route becoming unavailable for landing because of bad weather.

A typical ETOPS approval for carriers flying twin-engined aircraft today restricts them to routes that keep them within 180min single-engine flying time of a usable diversion airfield, although United Airlines has one Pacific approval for 207min - which it used fully in March 2003 when a Boeing 777 was forced to make a one-engine-inoperative diversion to Hawaii.

The initial response in the USA to the ETOPS revision - which applies only to US-registered aircraft - appears to be largely positive despite the addition of requirements that will, for first time, mandate additional equipment for carriage by trijets and quads flying polar, wilderness and oceanic routes with diversion airports more than 3h away.

To obtain ETOPS approval, all aircraft will need fire-suppression systems appropriate for the requested time-to-alternate, adequate emergency oxygen supplies for the crew and passengers to allow high-altitude flight to continue in the event of depressurisation, and automated external defibrillators. Weather reporting, training and diversion accommodation requirements have not been changed. The rule does not apply to three- and four-engined cargo aircraft.

Northwest Airlines, which operates 18 Boeing 747 passenger variants, says that it is continuing to study the rule, but "is confident we can meet the dates for compliance". United is the only other US carrier that operates passenger 747s, with a fleet of 30, according to Flight's Acas database.

Boeing Commercial Airplanes vice-president regulatory affairs Chet Ekstrand says the company had already "made the assumption" for what the final rule would look like, and has been "baselining" the changes for some time.

The new equipment rules for trijets and quads give operators time to prepare: they have a year to get their programme started, six years to install upgraded fire systems, and eight years to obtain certification for the modified aircraft.

Source: Flight International