ETOPS

History

The first non-stop transatlantic flight was made in 1919, by John Alcock and Arthur Brown, in a twin-engined Vickers Vimy. The flight from Canada to Ireland took sixteen hours. By 1936, the U.S. had introduced a rule, applied to all types of aircraft regardless of the number of engines, that restricted operations to an en-route area within 100 miles of an adequate airport. In those days 100 miles was about 60 minute flying time in many aircraft if an engine was inoperative. The "60-minute rule" was established in 1953, recognising the engine reliability of piston power plants that were available at that time. In general, twin-engined aircraft were restricted to areas of operation defined by 60 minutes from an adequate airport at the one-engine-inoperative cruise speed. However, the rule was flexible and exceptional approval could be obtained.

In the 1950s, Pan Am flew Convair 240s across the Caribbean, from Barranquilla to Kingston, Jamaica, and Avensa flew Convair 340s from Maracaibo to Montego Bay. Delta's Convair from New Orleans to Havana flew a longer trip but could arc north to stay within reach of an airport.

Early turbine engine experience

During the 1950s, the jet engine made inroads into civilian airliners, having been used almost universally in combat aircraft after World War II. Some British designs were already cleared for civilian use, and had appeared on early models like the de Havilland Comet and Avro Canada Jetliner.

By the 1960s, all large civilian aircraft were jet powered, relegating the piston engine to low-cost niche roles such as cargo flights. Pratt & Whitney jet engines were reliably powering the 2-engined DC-9 and Boeing 737 series, and 3-engined Boeing 727. The 60-minute rule was waived in 1964 for 3-engined aircraft, which opened the way for the development of wide-body, intercontinental trijets, such as the Lockheed L-1011 Tristar and DC-10. By then, only 2-engined jets were restricted by the 60-minute rule.

Early twin-engine high-bypass turbofan airliners

When the FAA restricted the twins to 60 minutes in 1953, ICAO limited it to 90 minutes at all-engine speed. Countries outside the US, which adopted the ICAO standards, permitted their airlines to operate up to 90 minutes. This allowed many twins to be operated in Southeast Asia and Australia without significant restriction.

Early ETOPS experience

Airbus A300 twinjet aircraft had been operated across the North Atlantic, the Bay of Bengal and the Indian Ocean under a 90-minute ICAO rule since 1976. However, ETOPS officially began in 1985 with the newly issued ETOPS criteria.

The FAA and ICAO concluded that a properly designed twin-engined airliner can make intercontinental transoceanic flights. In 1985 the FAA was first to approve ETOPS guidelines spelling out conditions for allowing a 120-minutes diversion period, sufficient for most transatlantic flights. Trans World Airlines was awarded the first ETOPS rating in May 1985 for the Boeing 767 service between St. Louis and Frankfurt, allowing TWA to fly its aircraft up to 90 minutes away from the nearest airfield: this was later extended to 120 minutes after a federal evaluation of the airline's operating procedures.

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. The use of the smaller 737-700 enabled Aloha to serve routes that could not support larger jet aircraft with an example being the Honolulu (HNL)-Burbank (BUR) nonstop route. Prior to the 737-700 operation, Aloha Airlines had operated 737-200 aircraft to various Pacific islands utilizing 120 minute ETOPS.

Early ETOPS

The original 1985 regulations allowed an airliner to have ETOPS-120 rating on entry into service. ETOPS-180 was only possible after one year of trouble-free 120-minute ETOPS experience. In 1990 Boeing convinced the FAA that it could deliver an airliner with ETOPS-180 on its entry into service. This process was called Early ETOPS. The Boeing 777 was the first aircraft to carry an ETOPS rating of 180 minutes at its introduction.

In the 1990s the Joint Aviation Authorities (JAA) disagreed and the Boeing 777 was rated ETOPS-120 in Europe on its entry into service. European airlines operating the 777 had to demonstrate one year of trouble-free 120-minutes ETOPS experience before obtaining 180-minutes ETOPS for the 777.

Before the introduction of the Airbus A350XWB in 2014, regulations in Europe and US permitted up to 180-minute ETOPS at entry. The A350XWB was first to receive an ETOPS-370 prior to entry into service by European authorities.

Extensions

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. This made 95% of the Earth's surface available to ETOPS flights. The first such flight was conducted in 1989. This set of regulations was subsequently adopted by the JAA, ICAO and other regulatory bodies.

In this manner the Boeing 737, 757 and 767 series and the Airbus A300-600, A310, A320 and A330 series were approved for ETOPS operations. The success of ETOPS aircraft like 767 and A300 made the intercontinental trijets obsolete for passenger use, as it did to the four-engined Airbus A340. This led Boeing to end the MD-11 program a few years after Boeing's merger with McDonnell Douglas, as well as to scale down the production of its own Boeing 747. The rules have also allowed American legacy carriers (United Airlines and Delta Air Lines in particular) to use the Boeing 757 on "long and thin" transatlantic routes between their major hubs and secondary European cities that cannot generate the passenger demand to justify the use of a widebody airliner. 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.

The cornerstone of the ETOPS approach is the statistics showing that the turbine assembly of a modern jet engine is an inherently reliable component. Engine ancillaries, by contrast, have a lower reliability rating. Therefore, an ETOPS-certified engine may be built with duplicate sets of certain ancillaries in order to receive the required reliability rating.

The North Atlantic airways are the most heavily used oceanic routes in the world. Most North Atlantic airways are covered by ETOPS 120-minute rules, removing the necessity of using 180-minute rules. However, some of the North Atlantic diversion airports are subject to adverse weather conditions making them unavailable for use. As the 180-minute rule is the upper limit, the JAA and FAA have given 15% extension to the 120-minute rules to deal with such contingencies, giving the ETOPS-138 (i.e. 138 minutes), thereby allowing ETOPS flights with such airports closed.

ETOPS-240 and beyond are now permitted on a case-by-case basis, with regulatory bodies in nations ranging from the USA, to Australia, to New Zealand adopting said regulatory extension. Authority is only granted to operators of two-engine airplanes between specific city pairs. The certificate holder must have been operating at 180-minute or greater ETOPS authority for at least 24 consecutive months, of which at least 12 consecutive months must be at 240-minute ETOPS authority with the airplane-engine combination in the application.

Exclusions

Private jets are exempted from ETOPS by the FAA, but are subject to the ETOPS 120-minute rule in JAA's jurisdiction.

Until the rule change in the US and Australia, several commercial airline routes were still economically off-limits to twinjets because of ETOPS regulations. There were routes traversing the Southern hemisphere, e.g., South Pacific (e.g., Sydney – Santiago, which is the longest over-the-sea distance flown by a commercial airline), South Atlantic (e.g., Johannesburg – São Paulo), Southern Indian Ocean (e.g., Perth – Johannesburg), and Antarctica. The carriers flying these routes, LAN Airlines, South African Airways, and Qantas, currently fly either Airbus A340, Boeing 747, or Boeing 787-9 aircraft on these routes.

Beyond ETOPS-180

Effective February 15, 2007, the FAA ruled that US-registered twin-engined airplane operators can fly more than 180-minute ETOPS to the design limit of the aircraft.

In November 2009, the Airbus A330 became the first aircraft to receive ETOPS-240 approval, which has since been offered by Airbus as an option.

On December 12, 2011, Boeing received type-design approval from the U.S. FAA for up to 330-minute extended operations for its 777-200LR, 777-300ER, 777F and 777-200ER equipped with GE engines, and with Rolls-Royce and Pratt & Whitney engines expected to follow. The first ETOPS-330 flight took place on 1 December 2015 with Air New Zealand connecting Auckland to Buenos Aires on a Boeing 777-200ER. On May 28, 2014, the Boeing 787 Dreamliner received its ETOPS-330 certificate from the FAA.

The first time that ETOPS-330 approval was given to a four-engined aircraft was in February 2015, to the Boeing 747-8 Intercontinental.

In October 2014 EASA certified the Airbus A350XWB to 370-minute ETOPS.

Ratings

The following ratings are awarded under current regulations according to the capability of the airliner:

However, ratings for ETOPS type approval are fewer. They are:

Approval

ETOPS approval is a two-step process. First, the airframe and engine combination must satisfy the basic ETOPS requirements during its type certification. This is called "ETOPS type approval". Such tests may include shutting down an engine and flying the remaining engine during the complete diversion time. Often such tests are performed in the middle of the ocean. It must be demonstrated that, during the diversion flight, the flight crew is not unduly burdened by extra workload due to the lost engine and that the probability of the remaining engine failing is extremely remote. For example, if an aircraft is rated for ETOPS-180, it means that it is able to fly with full load and just one engine for 3 hours.

Second, an operator who conducts ETOPS flights must satisfy their own country's aviation regulators about their ability to conduct ETOPS flights. This is called "ETOPS operational certification" and involves compliance with additional special engineering and flight crew procedures in addition to the normal engineering and flight procedures. Pilots and engineering staff must be qualified and trained for ETOPS. An airline with extensive experience operating long distance flights may be awarded ETOPS operational approval immediately, others may need to demonstrate ability through a series of ETOPS proving flights.

Regulators closely watch the ETOPS performance of both type certificate holders and their affiliated airlines. Any technical incidents during an ETOPS flight must be recorded. From the data collected, the reliability of the particular airframe-engine combination is measured and statistics published. The figures must be within limits of type certifications. Of course, the figures required for ETOPS-180 will always be more stringent than ETOPS-120. Unsatisfactory figures would lead to a downgrade, or worse, suspension of ETOPS capabilities either for the type certificate holder or the airline.