THE US AIR-TRANSPORT industry has begun discussions on how to overcome the growing danger that the US Department of Defense (DoD) base-closure programme could lead to a severe curtailment of twin-engine widebody operations across vital North Pacific routes. The move raises the prospect of extended-range twin-engine operations (ETOPS) limits having to be extended by 30min.

A joint Federal Aviation Administration/Air Transport Association (ATA) ETOPS committee met in Washington late in 1995 to discuss the issue. The committee, which includes members from Boeing and United Airlines, has agreed to consider options to overcome the problem, including extending ETOPS limits from 180min to 210min.

The issue has arisen because the cash-strapped DoD is closing key airfields in the Pacific which are designated to cater for diverted civil aircraft flying under existing ETOPS limits.

"We are stimulating discussion on the need to maintain bases, or find other means of staying within ETOPS-rule compliance if the bases are unavailable," says Don Collier, the ATA's director of operational engineering. "The work so far is very tentative," he adds.

The Aleutian Island bases of Adak and Shemya are being closed or downgraded, and Midway in the central Pacific has already had its runway approach aids withdrawn as part of the base rundown. Carriers such as Cathay Pacific have crossed the base from their list of available airfields. Wake and Johnson Islands are also being downgraded.

Adak and Shemya both provide 180min diversion cover for long-range twinjets using the great-circle tracks across the North Pacific. Because of minimum weather requirements, both airfields need to remain operational to provide continuous coverage.

ETOPS flights account for a relatively small proportion of the total traffic over the North Pacific,. This is set to grow with the introduction of new, longer-range, versions of the Boeing 777 and Airbus A330. If ETOPS coverage is compromised, carriers may be forced to use the more northerly G212 route to come within 180min range of Russia. The G212 route is restricted to four aircraft an hour.

The ATA says that Boeing representatives on the committee volunteered to carry out "the preliminary thinking" on the possibility of extending ETOPS, but adds that "all options" are being considered.

"It has always been our long-term strategy to go beyond 180min ETOPS, but as far as this issue is concerned, we have not yet made any plan," says Boeing.

Source: Flight International