Can a 777 Fly on One Engine?

Aircraft · 5 min read · Jul 18, 2022
can a 777 fly on one engine

While air transportation is deemed by some as the safest mode of transport, many people are afraid to fly, and different theories support their fears, although they are often incorrect. One of the most common theories that fuel people’s fear of flying is aircraft engine failure.

When flying on a single-engine aircraft the fear of having engine failure is more than acceptable. However, most passengers do not fly on single-engine aircraft, and the focus of this guide is on the Boeing 777, the largest twin-engine aircraft in the world, and whether or not a 777 can fly on one engine.

So, join us by reading below as we describe the truth behind flying on a “Triple Seven” with one engine.

Boeing 777: a twin-engine plane

The Boeing 777 is a passenger jet powered by two engines model GE90-115BL with “up to 115,000 pounds of thrust per engine” as described on Boeing’s website. While the website also claims “outstanding performance and reliability” we know they could eventually fail mid-flight. So, what happens in the rare situation of an engine failure?

Engine failure on a Boeing 777

One of the reasons why many people are afraid of engine failure is that there have been stories of catastrophic events related to engine failure before.

However, what people do not see is that thanks to the National Transportation Safety Board (NTSB), these events have gone through extensive investigation to discover what the problem was and take the corresponding measures which may even require replacing the engines completely.

Those investigations have brought up some of the most common causes of engine failure. According to the NTSB, they are fuel issues including delivery, exhaustion, contamination, or mismanagement. For example, worn hoses and fittings or bad or broken parts that are not replaced, or induction icing caused by pilot error forgetting to use the proper heat generation during descent.

The most recent story of engine failure reported involved a United Airlines flight from 328 San Francisco to Honolulu in February 2018. The pilot in command was forced to shut down an engine because the covering of the Pratt & Whitney engine that powered that Boeing 777 was lost. Fortunately, flight 328 made it to the destination airport with just one engine.

Several other similar stories involved Pratt & Whitney engines on 777s, so something had to be done. Did they change the engine casing that was apparently the problem? Not quite, because other incidents in flight involved fan blades and other components that forced airplanes to fly with only one engine. Therefore, the best option for the Boeing 777 was to replace the Pratt & Whitney with an other type of engine, which currently is the GE90-115BL from General Electric that was mentioned above.

A Cathay Pacific Boeing 777 taking off from the runway on a clear day.

Single-engine flying on a Boeing 777

In rare situations when an engine fails, single-engine flying has to be executed. But, how is this possible on a big airplane like the 777?

First of all, the Boeing 777 is designed and certified to fly with only one engine for up to five and a half hours. This means that the pilot has more than five hours to find the nearest suitable airport to land safely. Although this is considered an emergency landing, the truth is that is safer than it sounds thanks to the standard operating procedures that are set.

When one engine fails, the standard operating procedure states that the flight crew must call air traffic control, declare an emergency and reduce altitude to ensure the passenger jet can fly safely with only one engine and perform a safe emergency landing at the nearest airport.

Another point we must highlight is that aircraft like the 777s are flown by skilled licensed pilots who have received extensive training in dealing with situations like flying a 777 with one engine.

Can a 777 take off with one engine?

Taking off with one engine is a rare event for aircraft that are powered by two engines like the 777, or even those bigger ones powered by four engines. This is because comprehensive inspections are performed before this critical stage of the flight.

However, in the rare scenario when the engine fails during take-off, the pilot could actually complete the take-off and fly the plane to a safe landing provided there is enough runway.

So, while it is not ideal and it may be challenging, the answer should be yes, the 777 can take off with one engine only.

We have made it clear that the Boeing 777 can actually fly with one engine without much trouble. Whether it is fuel starvation, the fan blades, or any mechanical failure causing the engine to fail, if any of the jet engines fail, the remaining engine can help the plane fly safely.

Now, what about other aircraft? Can other big passenger jet fly when any of its engines fail? Let’s take a look at a couple of other aircraft.

The 747 “jumbo jet”

The first wide body aircraft considered a “jumbo jet” was the Boeing 747, which was also the first wide-body airliner. The newest version, the 747-8 has more than 400 seats available and it is powered by four GEnx-2B engines that provide enough speed to fly “the length of three FIFA soccer fields in one second” as described on the manufacturer’s website.

Can jumbo jets fly with one engine?

Jumbo jets like the 747 have more than two engines for one reason, they are massive. For jumbo jets, a single engine failure would not represent big trouble since they will have more than one engine to operate and reach a diversion airport to land safely. However, there is little chance this can be done with one working engine only.

Based on the experience of flight BA9 in 1982, when British Airways aircraft lost all four engines and started gliding, a jumbo jet requires at least two engines running to regain altitude, while a single engine would make it fly at a lower altitude in a continuous descent.

Yet, flying on a single engine, the 747 can at least help an experienced pilot extend the aircraft’s distance and prolong its time in the air in order to reach a suitable landing spot. Also, one engine would help ease the vertical force of impact and stretch out the distance for touching down. Fortunately, these situations are very rare.

A Lufthansa Boeing 747 Jumbo Jet parked on tarmac at an airport on a cloudy day.

The 787 Dreamliner

This is another twin-engine aircraft manufactured by Boeing that is said to have “unparalleled fuel efficiency and range flexibility”. This aircraft is powered by two GEnx-1B / Trent 1000 engines that provide a 20-25% better fuel per seat efficiency and emissions than others.

Can a Dreamliner plane fly with one engine?

Like the 777, the Boeing 787 Dreamliner can fly up to 330 minutes (five hours and a half) as a single-engine plane if one engine fails. This is supported by carrying an ETOPS-330 certification. The Boeing 787 Dreamliner may fly for longer than 330 minutes using a single engine, but this would require legal approval, based on safety concerns.

Performance will be affected like it happens with the 777, so keeping cruising altitude will not be possible, and the plane will find it more difficult to overcome drag. Yet, the Dreamliner will be able to continue flying. Of course, it will require a skilled pilot to complete the flight safely.

A United airlines Boeing 787 Dreamliner in flight across the blue sky.

Some final remarks on engine problems in commercial aviation

While things like fuel starvation and bird strike can cause engines to fail, the truth is that plane losses or accidents are rare. Some stats show that there is one engine failure per one million flights around the world, so this is not a common occurrence.

In summary, most aircraft can fly perfectly safely without some engines. However, it will depend on how many engines fail and how many remain functional. The bigger the plane, the more engines it will have and the more it will need to keep a safe cruise altitude and land safely. Of course, smaller aircraft with two engines are more capable of flying with one engine only since they are designed to withstand such situation.

Finally, if you are flying at maximum altitude and there is an engine failure, you now know you do not need to panic. Your trained pilot will take all the necessary measures and the plane will react accordingly. Odds are in your favor, and the most likely is that you will end up telling the story of how the plane landed safely.

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Carlos Collantes
Carlos Collantes
A mechanical engineer and aviation enthusiast dedicated to share some knowledge by creating top-notch content, especially in engineering and aviation topics.

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