Federal Aviation Regulation (FAR) 121.161 states "Unless authorized by the administrator, based on the character of the terrain, the kind of operation, or the performance of the airplane to be used, no certificate holder may operate two-engine airplanes over a route that contains a point farther than 1 hour flying time (in still air at normal cruising speed with one engine inoperative) from an adequate airport." The rule was written in the days of the propliner when piston engines didn't have the reliability of modern jet turbines. When the Boeing 767-200ER entered service, it was the first commercial twin-jet capable of crossing the oceans*- when Boeing's director of engineering, Dick Taylor, first approached FAA administrator Lyn Helms in 1980, Helms responded "It'll be a cold day in hell before I let twins fly long haul, overwater routes." Helms even felt that the 60-minute rule was too generous. Despite his opposition, though, in 1982, the FAA began technical discussions with aircraft manufacturers, airlines and ICAO (they had formed a study group of their own in 1982) on the possibility of extended twin-engine overwater flights. At an ICAO meeting in Montreal that December, the FAA asked airline operators of twin jet aircraft to compile a database of inflight events and engine shut downs. Since long range commercial twins were relatively new to the market, the FAA needed a database to draw upon in figuring out the regulatory details of what would become ETOPS flying. After the Air Canada Flight 143 incident (the "Gimli Glider) where fuel starvation resulted in a skillful emergency landing on an old Canadian military air strip, some thought it a set back for what Dick Taylor had been pushing for with the Boeing 767. However, in a speech to the Royal Aeronautical Society in London in late 1983, he argued that fuel starvation would have shut down all the engines regardless of whether you have two, three, or four engines.
|N767BA, the Boeing 767 prototype|
(Seattle Municipal Archives via Wikipedia)
In 1980 three- and four-engined aircraft handled all the long range routes, particularly those that were overwater. There was a joke that stated "The reason I fly four-engined aircraft across the ocean is because there are no five-engined aircraft." But modern technology and computerized systems brought to the Boeing 767 a level of redundancy, safety, and efficiency not seen in any prior commercial aircraft. And it wasn't just the reliability of the engines, the various systems of the 767 facilitated the development of ETOPS- Extended-range Twin-engine Operational Performance Standards- the ability of a twin engine jetliner to exceed the old 60-minute rule.
*I should point out at this point that before the 767, some Airbus A300 operators were flying overwater routes beyond the FAA's 60-minute rule under ICAO regulations, but that's beyond the scope of this article and I'll be touching upon the A300 in a future article on ETOPS history.
For two years Boeing collected reams of data on the first 767 operations, compiling information on every shutdown and failure of any system including the engines in the first two years of commercial airline services. This was supplemented by the FAA/ICAO database that was started in 1982. In April 1984 El Al Israel Airlines became the first airline to operate the 767 on trans-Atlantic services between Montreal and Tel Aviv, but the aircraft's routing complied with the 60-minute rule. Not long after, El Al, Air Canada, and Trans World Airlines (TWA) received exemptions to operate no more than 75 minutes from a suitable diversion airport. This would open up some trans-Atlantic routes and Caribbean routes to the 767. In fact, Air Canada was the first to crack the 60-minute barrier having earned its 75-minute exemption in late 1983. By this point Lyn Helms was no longer the FAA Administrator, the post now assumed by Donald Engen who was more open minded to extended twin overwater flights. (Engen would later become the head of the National Air & Space Museum) Interestingly and perhaps not surprisingly, one of the biggest opponents of ETOPS at the time was McDonnell Douglas, who saw the future of the DC-10 line threatened by the 767.
In June 1984 Boeing showcased the new 767-200ER's long legs with a 7,500 mile delivery flight from Washington Dulles to Addis Adaba, Ethiopia to bring the 767 to Ethiopian Airlines. The flight required a special one-time FAA waiver to take place. In October 1984 Air Canada took delivery of the first ETOPS-qualified 767-200ER which was permitted to go 75 minutes from a suitable diversion airport. The International Civil Aviation Organization (ICAO), the International Federation of Air Line Pilots Association, the US-based pilots' union Air Line Pilots Association (ALPA) and the FAA made several recommendations to Boeing that resulted in the 767-200ER having a fourth electrical generator independently powered by a hydraulic motor, additional fire suppression features and equipment for cooling of the CRT displays in the cockpit.
By 1985 Dick Taylor at Boeing was lobbying the FAA hard for extension of the 75-minute rule to 120 minutes which would open up a large number of trans-Atlantic routes to the 767. Already several airlines led by TWA had petitioned the FAA for an ETOPS extension to 120 minutes but before the FAA would grant the extension, Boeing had to show "statistical maturity" by equipping a number of 767s with special data gathering equipment to show unparalleled standards of inflight reliability and the Pratt & Whitney JT9D engines had to log 250,000 consecutive flight hours on passenger flights with a very low rate of shutdown.
|Trans World Airlines made the first 120-minute ETOPS flight in 1985|
(Jon Proctor Collection via Wikipedia)
On 1 February 1985, TWA Flight 810 departed Boston for Paris on the first revenue passenger flight in history under the 120-minute ETOPS rule. The new ETOPS rule shortened the flight distance and it would replace a Lockheed L-1011 Tristar that normally served the route. Before Flight 810 departed, sixteen TWA pilots went through specialized ETOPS training on international requirements, intensive time in a simulator and landing procedures for the airport at Sondrestromfjord in Greenland, the designated 120-minute diversion airport. Eleven observers from the FAA were aboard TWA 810 and the fuel burn was found to be 7,000 lbs an hour less than that of the L-1011 Tristar on the same route. TWA was so convinced of the efficiency of the 767 with the 120-minute ETOPS rule that it spent $2.6 million per aircraft retrofitting all of its 767-200s for 120-minute ETOPS compliance.
But Boeing and Dick Taylor didn't stop there. The existing 120-minute ETOPS rule wasn't enough to get the 767 to Hawaii from California. But Boeing continued to compile failure and shutdown data on the 767 on the trans-Atlantic route to prove the the FAA that it was possible to safely operate the 767 to Hawaii from the US mainland. In 1989, the FAA approved the ETOPS extension to 180 minutes which opened up Hawaii to the 767, as the halfway point between Hawaii and the US mainland is approximately 150 minutes' flying time. But to gain the 180-minute extension, a particular aircraft and engine combination had to show 12 consecutive months of 120-minute ETOPS flights and meet stringent engine failure rates. The first 180-minutes ETOPS flights were made by American Airlines on the DFW-Honolulu routing starting in 1989. By 1993 the entire 767 family, both the -200 and the -300, as well as the possible engine options of GE, Pratt & Whitney, and Rolls-Royce, gained full 180-minute ETOPS extensions.
|The first commercial 180-minute ETOPS flights were made by American 767-300ERs DFW-HNL|
(Aero Icarus Collection via Wikipedia)
By 1991 the number of passengers crossing the Atlantic on 767s exceeded the number of passengers crossing on three- and four-engined aircraft for the first time in history. By 2000, over 50% of all trans-Atlantic crossings were being made by the 767 family of aircraft. By that time, all brand new 767s rolling out at Boeing's factory in Everett were certified for 180 minutes ETOPS extensions.
It will be the legacy of the Boeing 767 to show that any place in the world could be crossed safely and efficiently with only two engines and it set the stage for the arrival of the Boeing 777 and Airbus A330 family of aircraft that routinely fly routes today that were once the exclusive domain of multi-engined aircraft like the Boeing 747, A340, DC-10/MD-11 and L-1011 Tristar.
Source: Boeing 757 and 767 (Crowood Aviation Series) by Thomas Becher. The Crowood Press, 1999, p145-155.
Post a Comment