Modern twin-engine planes are able to fly and even take off and land with only one engine.

But, depending on the plane, flying with one engine can be more dangerous than others, and it takes a skilled pilot to fly and more importantly land a plane with just one working engine.

While there are many single-engine planes, most commonly, pilots fly planes with one only working engine when the other engine is damaged during flight.

Engine failure can occur for a number of reasons that we cover below.

Not All Planes Can Fly With One Engine

A twin-engine plane is able, to some extent, safely fly and land with a single engine, but it’s not ideal.

In the event of engine failure in a single engine plane, though, a subsequent forced emergency landing is required.

Private Planes

Most private planes only have one engine, which means that an immediate emergency landing is required.

Many private planes are equipped with multiple engines, though, which means that they can fly even if one engine fails. 

Commercial Planes

Only commercial planes with an ETOPS certification are legally allowed to fly routes over places where landing areas are sparse or non-existent.

It used to be the case that planes with ETOPS certification were only allowed to fly 60 minutes away from the nearest air strip or airport.

However, this has been changed to planes now being able to fly as far as five and a half hours away from the closest airport.

This just goes to show that while an engine failure is by no means ideal, commercial planes that passengers use every day are safe even if a single engine failure occurs.

Military Jets

Twin-engine military planes are designed to fly if one engine suffers failure.

Military planes are only expected to return to base or at least land in friendly territory when one engine fails. 

How a Plane is Able to Fly With One Engine

While planes can fly with just one engine, flight with a single engine is never ideal and requires highly trained pilots to navigate.

Typically, when one engine fails, the aircraft’s other engine increases its thrust to compensate for the decrease in speed.

Since an aircraft engines are normally located on opposite sides of the aircraft, when one engine fails, it causes the aircraft to pivot away from the working engine.

If the aircraft isn’t properly handled, this can result in loss of control of the aircraft.

Usually, aircraft can’t maintain proper cruise altitude with one engine.

Large planes, especially, cannot properly cruise with only one engine.  

What the Pilots Do If an Engine Fails

A pilot’s response to engine failure depends on the extent of the damage.

For example, if an engine fails because it catches fire, the flight crew will immediately respond. They will shut down the engine and attempt to extinguish the fire.

If successful, and the engines turn back on, the plane will continue flying until it reaches the nearest airport where it will descend for safety checks.

If the extent of damage is too severe and impossible for flight crews to mitigate, the pilots will immediately land the aircraft at the next safest possible destination. 

How Far a Plane Can Fly With One Engine

Twin engine planes that can fly with one engine have an ETOPS (Extended-range twin-engine Operational Performance Standards) certification.

This certification allows twin-engine planes to fly up to five and a half hours away from the closest airport or air strip.

The exact time depends on the aircraft, so some planes fly longer with one engine.

For example, the Boeing 787 Dreamliner has an ETOPS-330 certification, which means that it can fly up-to 330 minutes with a single engine.

The Boeing 787 Dreamliner could potentially fly longer than 330 minutes with a single engine, but it’s not legally permitted to do so because of safety concerns. 

Related: How Many Engines Does a Plane Have?

6 Reasons Why A Plane’s Engine Might Fail

Carburettor Icing

High humidity causes carburettor ice to form during taxiing.

Carburetor ice is both difficult to detect at lower power settings, and it jams mechanical parts of the carburetor.

Parts that get damaged by carburettor ice include the throttle.

Carburettor icing causes particular damage to small piston-powered aircraft since they’re less well-equipped with heating systems for melting the ice. 

Air Blockage

Blockage in the carburettor air filter can also cause engine failure.

The blockage prevents proper air flow through the carburettor, resulting in the engine not being able to properly function. 

Fuel Contamination

Fuel contamination is the most common cause of engine failure.

Most commonly, fuel contamination is caused by the presence of water in the fuel.

Although pre-flight checks are normally performed on aircraft fuel, sometimes contaminations go undetected.

These contaminations damage the engines and prevent them from working properly. 

Fuel Starvation

Fuel starvation refers to when on-board fuel doesn’t reach the engine.

Most often, fuel starvation happens when pilots select the wrong fuel tank or accidentally place fuel selectors in the OFF position.

Fuel starvation can also be caused by engine-driven fuel pump failure, blocked fuel lines, or blocked fuel vents and fuel injectors. 

Fuel Exhaustion

Fuel exhaustion refers to the absence of fuel on the plane.

The most common reason for fuel exhaustion is due to logistical mistakes or bad decision-making.

Fuel exhaustion can also be caused by the fuel caps not being closed.

Mechanical Failure

Planes use different types of engines, like piston engines or turboprop engines.

These engines are susceptible to varying degrees of mechanical failure.

Likelihood of a Plane Having An Engine Failure

There are 25 jet engine failure incidents every year.

This statistic translates to approximately one engine failure incident per one million flights in the world.

The likelihood of engine failure is low because flight crews are extensively trained on how to prevent one from occurring.

Additionally, strict safety checks also ensure that engine failure is avoided as much as possible. 

Statistically, turbine engines have a failure rate of one per 375,000 flight hours, compared to of one every 3,200 flight hours for aircraft piston engines

What Happens If a Plane’s Engine Fails Over the Ocean?

Typically, when a plane suffers engine failure over the ocean, the pilot will try to land the plane at the nearest airport.

For example, a plane flying from Denver to Honolulu would normally be required to be able to land over a diversion airport.

However, if not possible, a plane may have no option but to land in the ocean.

Related: Why Don’t Planes Fly Over the Pacific Ocean?

A Plane Can’t Fly Without Any Engines

No, planes cannot fly without engines. At best, modern planes could temporarily glide without engines.

Most modern planes are designed to temporarily glide over long distances if they suffer complete engine failure, but it’s not possible for a plane to take off without engines. 

In conclusion, most modern planes can fly with one engine. But depending on the plane, one engine flights can be difficult and dangerous, so most pilots avoid them whenever possible.

Helen Krasner holds a PPL(A), with 15 years experience flying fixed-wing aircraft; a PPL(H), with 13 years experience flying helicopters; and a CPL(H), Helicopter Instructor Rating, with 12 years working as a helicopter instructor.

Helen is an accomplished aviation writer with 12 years of experience, having authored several books and published numerous articles while also serving as the Editor of the BWPA (British Women Pilots Association) newsletter, with her excellent work having been recognized with her nomination of the “Aviation Journalist of the Year” award.

Helen has won the “Dawn to Dusk” International Flying Competition, along with the best all-female competitors, three times with her copilot.