What Is ETOPS? What Every Aviator Needs to Know

ETOPS stands for Extended-range Twin-engine Operations Performance Standards.

Ever wonder why we see fewer and fewer triple or quad-engine airplanes, even for long-haul flights at the major airports?

Sadly (at least for plane nerds who love more engines!), Boeing and Airbus have stopped making their 747 and A340/380 aircraft. These big planes were once the dominant fleet for long overseas routes, but now they’re getting retired.

The answer to where these masterful machines went is complicated, but changes in the rules known as ETOPS have been a major factor in their retirement.

Let’s look at ETOPS, what it means, and why it means that long-range twin jets are all the rage. 

What Is ETOPS?

As I said in the beginning, ETOPS stands for Extended-range Twin Operations Performance Standards.

The first rules came from ICAO, the International Civic Aeronautics Organization, a UN branch regulating standardized aviation worldwide. The FAA soon started adopting them, as well. 

Ask a pilot, and they might answer differently: ETOPS means “Engines Turn or Passengers Swim.” And that sums it up because the ETOPS rules are all about being close enough to land in case of an engine failure.

To understand the importance of ETOPS, you must first be familiar with FAR Part 121.161.

In summary, it states that an airline cannot operate a twin-engine aircraft on a route that puts it more than one hour away from an adequate airport at normal cruising speed on one engine.

If it’s a plane with more than two engines, then it can fly routes that are 180 minutes away from an adequate airport. 

The ETOPS rules were developed to extend that time beyond one hour for twins.

As aircraft engines have become more reliable and technology advanced, the time required to get to the alternate airport has been gradually extended.

Increasing this time factor by a few minutes may seem simple, but it has major repercussions for airlines. 

History of ETOPS

The basis of ETOPS, the “60-minute rule” from Part 121, has existed since the earliest days of aviation.

In the late 1930s, twin-engine planes were only approved for routes with alternate fields at least every 100 miles. That became the 60-minute rule in the 1960s and was applied to twin and tri-engine aircraft.

Triple-engine planes like the L-1011 and DC-10 were soon exempted.

In the 1980s, a new generation of twin-engine aircraft entered service. They were thoroughly modern, with redundant, computerized systems and enough built-in safety features for extended overwater flying.

The FAA issued AC 120-42, which outlined a way to get approval to waive the 60-minute rule for twinjets. 

The Airbus A300 was the first twin that benefited from ETOPS rules, flying under special rules from ICAO on Atlantic crossings. The Boeing 767-200ER was the first US aircraft that could benefit from ETOPS—it had a 7,500-mile range.

In 1984, it was authorized to travel 75 minutes from an alternate airport (ETOPS-75). By the mid-80s, it had been extended to 120 minutes (ETOPS-120), which opened several new routes across the North Atlantic. 

Different ETOPS Ratings

Each aircraft gets a different ETOPS rating depending on its designs and capabilities and the operational history and reliability of the engines installed.

Possible ratings range from ETOPS-75 to ETOPS-370. With an ETOPS-180/207 rating, a plane can go nearly anywhere—over 95 percent of the Earth’s surface. 

Engine reliability is the major factor affecting certification.

To get ETOPS-120, an engine must be shown to have an in-flight shutdown rate better than 1 in 20,000 hours. It must be better than 1 in 100,000 hours to get ETOPS-180.

The Boeing 777 was the first aircraft to enter service with a 180-minute authorization.

Now, an aircraft can be certified for even longer intervals. For example, the Airbus A330 was certified by the FAA for ETOPS-240, and the new A350XWB has been granted ETOPS>180, and ETOPS-370 is pending approval. The Boeing 787 Dreamliner is approved for ETOPS-330.

Why Is ETOPS Important?

Here’s an example of why ETOPS matters to airlines.

The first revenue ETOPS-120 flight was TWA Flight 810 in 1985. The flight was made by a Boeing 767-200 from Boston to Paris.

ETOPS-120 allowed the company to use a twin-engine B-767 instead of the tri-jet L-1011, saving the company 7,000 pounds of fuel per hour.

TWA was so convinced of the potential savings that it spent $2.6 million to retrofit its fleet of 767s to meet the ETOPS-120 standards.

ETOPS-120 helped the airlines cross the Atlantic, but it couldn’t fly a plane to Hawaii.

To do that, ETOPS-180 was needed. By 1993, all variants of the 767 family were granted ETOPS-180, and routes to Hawaii were being flown. 

ETOPS Today

One of the major changes to ETOPS lately is its inclusion of aircraft with more than two engines.

As technologies have improved and systems have been designed for greater safety, the FAA and ICAO have realized that many of their twin-jets requirements should apply to tri and quad-jets, too.

To that end, ICAO has changed its terminology to reflect the current rules better. Today, these rules are part of EDTO, or Extended Diversion Time Operations.

The FAA still uses “ETOPS” or simply “extended operations” to refer to these rules. They apply no matter how many engines a plane has, be it twin, tri, or quad. 

Besides aircraft type approval, airlines must also satisfy their country’s requirements to become ETOPS certified. This proves that pilots and engineers have received training on ETOPS procedures.
Current FAA ETOPS rules are discussed in AC 120-42B.