Boeing is seeking a fundamental revision of the rules governing extended-range twin-engined operations (ETOPS), which would allow its 777 unlimited access to remote route sectors more than 180min from the nearest diversion airport.

The move follows a request for a 15% extension to 180min ETOPS restrictions that the US Federal Aviation Administration is expected to approve soon. This would permit carriers an exemption to operate the twin-engined 777 up to 207min from the nearest airport.

"We don't think the methodology of using incremental steps of 120min, 180min - and some have talked about the next being 240min - makes sense," says Boeing ETOPS vice-president Chet Ekstrand. "We built the 777 to have reliability and redundancy for unlimited ETOPS."

Boeing is proposing a shift from the current "prescriptive" rule-making policy to a "performance-based methodology" that evaluates individual airframe/engine combinations to determine range ratings. It contends that the 777, with an inflight shutdown rate of 0.020/100 engine hours, is equal to or better than the propulsion-related risk of a four-engined 747.

The company says that, with engines now 10 times more reliable than when twin-engine restrictions were first adopted in 1953, it is time for a "reformulation of ETOPS-related policy".

Ekstrand claims that the "FAA is willing to move forward with a new policy", and that the European Joint Aviation Authorities "recognises ETOPS requirements are overdue for an update".

Even with a 207min ETOPS exemption, there are still parts of the South Pacific that remain off limits to twinjets. The 15% extension to 207min that the US Air Transport Association (ATA) is seeking on behalf of American Airlines, Continental Airlines, Delta Air Lines and United Airlines, would close the 5-13min gap that would exist in the North Pacific should the six designated diversion airfields in Alaska, the Aleutian Islands and Russian Far East all be closed by weather or volcanic activity.

All four US carriers have launched, or are about to launch, 777 services to Japan. Some of these airfields have been threatened with closure because of US defence cuts. Concern over ETOPS and the future status of Midway Island was a critical factor in Singapore Airlines' decision to select the Airbus A340-500 over the 777-200X in 1998.

A joint ATA subcommittee, which included the airline pilot unions and Airbus, is about to recommend to the FAA a 15% 777 ETOPS extension. "We believe that recommendation is unanimously supported-there is nothing that precludes its use on other aircraft," says Ekstrand.

Source: Flight International