Guy Norris/LOS ANGELES
United Airlines is the first airline to receive US Federal Aviation Administration approval to use its Boeing 777-200ERs on extended-range twin-engined operations (ETOPS) services on transpacific routes that take aircraft up to 207min single-engined flying time away from the nearest diversionary airfield.
United was one of several carriers that sought a 15% extension to the standard 180min ETOPS restrictions in 1998 to close a 5-13min gap that exists on certain north Pacific routes under extreme conditions. These include bad weather or volcanic activity which can affect six designated diversionary airfields in Alaska, the Aleutian Islands and the Russian Far East.
The other carriers in the group, which sought the exemption through the US Air Transport Association, include American Airlines, Continental Airlines and Delta Air Lines.
United, which was granted clearance to invoke the 207min ETOPS route on a "case by case" basis on 1 May, says: "We intend to use it when needed, which we predict will be about 10% of the time". The move follows campaigning by Boeing, which emphasised a shift from "prescriptive" rule-making policies to "performance based methodology" in which individual airframe/engine combinations are used to determine range ratings.
Boeing contended that the 777's inflight shutdown rate of 0.020/100 engine hours (at the time of the application) was equal to or better than the propulsion-related risk of a four-engined 747
Source: Flight International
