This may be at a reduced speed and/or height, and usually applies to flights over water or remote lands, typically routes previously restricted to three- and four-engine aircraft.
[1]: page9 In 1936, the predecessor to the Federal Aviation Administration (FAA), the U.S. Bureau of Air Commerce, restricted commercial operations within United States airspace to within 100 miles (160 km) of an adequate airport.
Meanwhile, the International Civil Aviation Organization (ICAO) recommended a 90-minute diversion time for all aircraft, which was adopted by many regulatory authorities and airlines outside the US.
More recently, the January 1979 OAG showed a weekly Polynesian Airlines HS748 from Niue to Rarotonga, 585 nmi (1,083 km; 673 mi) with no airport.
Airbus A300 twinjets, the first twin-engine wide-body aircraft, had been flying across the North Atlantic, the Bay of Bengal, and the Indian Ocean under a 90-minute ICAO rule since 1976.
[1]: page14 When the FAA director J. Lynn Helms in 1980 was approached about the possibility of an exemption, his response was "It'll be a cold day in hell before I let twins fly long haul, overwater routes.
The 767 burned 7,000 lb (3.2 t) less fuel per hour than a Lockheed L-1011 TriStar on the same route, prompting TWA to spend $2.6 million on each 767 they owned to retrofit them to ETOPS-120 specs.
[1]: page14 In 1988, the FAA amended the ETOPS regulation to allow the extension to a 180-minute diversion period, subject to stringent technical and operational qualifications.
Effective February 15, 2007, the FAA ruled that US-registered twin-engine airplane operators can fly more than 180-minute ETOPS to the design limit of the aircraft.
The A350 XWB was first to receive an ETOPS-370 prior to entry into service by European authorities,[14] enabling economical nonstop routes between Europe and Oceania (and thereby bypassing historical stopovers across Asia and North America) by the late 2010s and early 2020s.
The A350 XWB's current ETOPS certification covers 99.7% of the Earth's entire surface, allowing point-to-point travel anywhere in the world except directly over the South Pole.
During the Cold War, routes between Europe and East Asia were prohibited from flying over Soviet Union or China since both airspaces were previously heavily military-controlled.
They flew near the North Pole with a very large distance to usable airports, for which only three- and four-engine wide-body aircraft were permitted for safety reasons by international aviation authorities.
Some flights between Europe and Oceania still largely pass through stopovers in Asia (either in the Middle East or Southeast Asia) or North America (either in Canada or the U.S.) given the current aircraft range restrictions and, in the case of the early and mid-2020s, the reinstatement of selected routes by airlines between the Western Hemisphere and Eastern Hemisphere bypassing Russia due to its ongoing war with Ukraine.
The practice has been controversial, because although the 757 has adequate range to cross the Atlantic Ocean comfortably, strong headwinds caused by the jetstream over the winter months can result in westbound flights being declared "minimum fuel", forcing a refuelling stop at Gander, Newfoundland, in order to safely complete their journey.
[17] Aloha Airlines operated 180-minute ETOPS–approved Boeing 737-700 aircraft on nonstop routes between the Hawaiian Islands and the western U.S. and also Vancouver, Canada.
By the mid-2010s, the widespread successes of ETOPS-reliant narrow-body aircraft have diminished the global market share of double-deck wide-body jets.
The cornerstone of the ETOPS approach is the statistics showing that the turbine assembly of a modern jet engine is an inherently reliable component.
Unsatisfactory figures would lead to a downgrade or, worse, suspension of ETOPS capabilities either for the type certificate holder or the airline.
This final rule codifies current FAA policy, industry best practices and recommendations, as well as international standards designed to ensure long-range flights will continue to operate safely.
"[20] and Several commenters … recommended use of the acronym "LROPS"—meaning 'Long Range Operations'—for three- and four-engine ETOPS, to avoid confusion, particularly for those operations beyond 180 minutes' diversion time.
"[21]Prior to 2007, the FAA used the term for Extended Range Operation with Two-Engine Airplanes but the meaning was changed when regulations were broadened to include aircraft with more than two engines.