ETOPS
Safety standards for twin-engine aircraft over long-distance routes.
ETOPS stands for Extended-range Twin-engine Operations Performance Standards, sometimes also called Extended Twin Overwater Passenger Service. These safety standards, established by the International Civil Aviation Organization (ICAO), apply to twin-engine commercial passenger planes. The core idea is that if one engine fails, the aircraft can still reach a suitable alternate airport using the other engine, even if it has to fly slower or at a lower altitude. Such rules are especially important for long flights over oceans or remote regions, which used to be flown only by planes with three or four engines. Twin-engine airliners are generally limited to areas within one hour of flying time (on one working engine) from a suitable airport. Higher certifications, like ETOPS-90, push that to 90 minutes, and ETOPS-180 extends it to 180 minutes. Similar limits now apply to three- and four-engine planes as well. The term "ETOPS" is still sometimes used for these rules, but other names have been introduced to drop the "twin" reference. In 2017, ICAO issued Standards and Recommended Practices (SARPS) for ETOPS, and ETOPS were extended to four-engine aircraft like the Boeing 747-8 and the terminology updated to EDTO (Extended Diversion Time Operations). The European Union Aviation Safety Agency had earlier used "Long Range Operations" (LROPS) for restrictions on planes with three or four engines.
In 1936, the U.S. Bureau of Air Commerce, a forerunner of the FAA, restricted commercial flights within the U.S. to within 100 miles (160 km) of an adequate airport. For many planes of that time, this meant about 60 minutes with one engine out. By 1953, better piston engine reliability and aircraft performance led U.S. authorities to adopt a "60-minute rule," limiting twin-engine planes to a 60-minute diversion area (at single-engine cruise speed). Some extra flexibility was allowed with special approval. Meanwhile, ICAO recommended a 90-minute diversion time for all aircraft, a standard many regulators and airlines outside the U.S. adopted. During the 1950s, several twin-engine planes flew routes that would later be governed by ETOPS rules. Pan Am operated Convair 240s across the Caribbean from Barranquilla, Colombia to Kingston, Jamaica. Avensa flew Convair 340s from Maracaibo, Venezuela to Montego Bay, Jamaica.
- Initial restriction 1936
- 100 miles (160 km) of an adequate airport
- First 120 minute etops service
- February 1, 1985, by Trans World Airlines with a Boeing 767-200 from Boston to Paris
- First aircraft with etops 180 on entry
- Boeing 777
- First aircraft to receive etops 240 appr
- Airbus A330 in November 2009
- First etops 330 flight
- December 1, 2015, by Air New Zealand connecting Auckland to Buenos Aires on a 777-200ER
- First aircraft to receive etops 370 prio
- Airbus A350 XWB in 2014
Lore & Background
In 1936, the U.S. Bureau of Air Commerce restricted commercial operations to within 100 miles of an adequate airport. In 1953, improvements led to a 60-minute rule for twin-engine aircraft, while ICAO recommended a 90-minute diversion time. During the 1950s, various twin-engine aircraft flew overwater routes, including Pan Am Convair 240s across the Caribbean and KLM Douglas DC-3s. In 1964, the 60-minute rule was waived for three-engine aircraft, allowing trijets like the Lockheed L-1011 TriStar and McDonnell Douglas DC-10 to dominate long-haul flights. Airbus A300 twinjets had been flying under a 90-minute ICAO rule since 1976. In 1985, the FAA increased ETOPS to 120 minutes, and TWA operated the first ETOPS-120 service. In 1988, the FAA allowed extension to 180 minutes, covering about 95% of the Earth. The Boeing 777 was the first aircraft introduced with ETOPS-180 on entry into service. In 2007, the FAA ruled that US operators could fly beyond 180 minutes to the design limit. In 2017, ICAO issued Standards and Recommended Practices for ETOPS, extended them to four-engine aircraft, and updated terminology to EDTO (Extended Diversion Time Operations).
Reader's Guide
ETOPS regulations have significantly shaped commercial aviation by enabling twin-engine aircraft to operate on long-distance routes over water and remote areas, which were previously restricted to three- and four-engine aircraft. The standards evolved from early 60-minute and 90-minute rules to ETOPS-180, covering about 95% of the Earth, and later to ETOPS-240, ETOPS-330, and ETOPS-370. The Boeing 777 was the first aircraft to receive ETOPS-180 on entry into service, and the Airbus A350 XWB was the first to receive ETOPS-370 prior to entry. These extensions allowed airlines to operate more fuel-efficient twinjets on routes like Auckland–Buenos Aires and Santiago–Auckland–Sydney, which were previously economically off-limits. The terminology was updated to EDTO in 2017 to remove the 'twin' reference, as the standards were extended to three- and four-engine aircraft. The European Union Aviation Safety Agency previously used the term Long Range Operations (LROPS) for restrictions on airliners with three or four engines.
Did You Know?
- In 1980, FAA director J. Lynn Helms responded to a request for twin-engine long-haul overwater flights with 'It'll be a cold day in hell before I let twins fly long haul, overwater routes.'
- The Boeing 767-200ER burned 7,000 lb (3.2 t) less fuel per hour than a Lockheed L-1011 TriStar on the same route.
- ETOPS-180 and ETOPS-270 cover about 95% of the Earth.
- The Airbus A350 XWB's ETOPS certification covers 99.7% of the Earth's entire surface.
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