If you’ve every wondered how many engines a plane has, the answer varies depending on the type of plane, as planes have engines according to their needs.
Small planes normally only have one engine, but large commercial planes have between 2 and 4.
The world’s largest cargo planes have as many as 8, and future aircraft may have as many as 16.
The largest planes need more engines to fly safely and efficiently, compared to smaller planes that aren’t equipped with multiple engines.
A benefit of large commercial planes having multiple engines, is that in case of engine failure, they can still safely make an emergency landing.
Aircraft engines are very expensive, so most airlines purchase them as part of maintenance and repair packages to reduce costs.
Most small planes have a single piston-powered engine due to their size.
Some small planes, like the Harbin Y-12, have two engines, but they are extremely rare.
Most small planes just don’t need multiple engines.
Private Jets
Most private jets have 2 engines, but larger ones can have 3 or more.
For example, the Dassault Falcon 900 has 3 engines, since it’s one of the larger private jets.
Commercial Airliners
Commercial airliners have between 2 and 4 engines.
Popular commercial airlines like the Boeing 787 and Airbus A320 have two jet engines, but wide body designed aircraft like the Boeing 747 or Airbus A380 have 4 engines.
It’s extremely rare for commercial airliners to have 3 engines because of the operating costs and fuel inefficiency of a plane running three engines.
Military Planes
Most fighter jets have a single engine, except air superiority fighters, which have 2.
Military cargo planes and bomber planes usually have 4 engines, and the largest cargo planes can even have 8.
Why Commercial Airliners Have Four Engines
Commercial planes have 4 engines due to the several advantages they offer.
Large commercial airliners can carry more passengers, which in turn means that they require more engines, so it is more economical to have 4 engines.
Another benefit of having 4 engines is increased thrust.
Airliners use thrust to propel aircraft through the air and overcome drag. So, having 4 engines helps airliners fly more easily through the air.
Having 4 engines also makes commercial airliners safer.
An airplane is much likelier to survive engine failure, the more engines it has.
If a single engine fails, then a commercial airliner can use the other 3 to safely continue to fly and make an emergency landing.
So, having 4 engines is the rational option for most commercial airliners.
Some experimental planes like the electric NASA X-57 Maxwell are designed to carry 18 electric engines.
A Plane Can Still Fly With Engine Failure
Aircraft can fly with engine failure as long as they have another working engine to rely on.
As planes are able to fly because of air continually moving over their wings, when an engine fails, a plane finds it harder to push forward through thrust.
But if an airplane during engine failure decreases altitude, it can still maintain its airspeed.
An airplane will eventually crash if all its engines fail, so most planes also have multiple engines for that reason.
Many planes have successfully landed after suffering engine failures.
For instance, US Airways flight 1549 suffered engine failure after striking a flock of birds and made an emergency landing.
All 155 people onboard the aircraft survived the emergency landing.
So planes can survive engine failures as long as they have other engines and are able to slowly descend to the ground.
In the event of engine failure in a single engine plane, though, a subsequent forced emergency landing is required.
How Much Does a Plane Engine Cost?
Jet engines cost between $10 million to $40 million each, so they’re undoubtedly an expensive purchase for airlines.
Aircraft manufacturers usually provide spare engines in maintenance packages to airlines – these deals are easily worth several billions of dollars.
Propeller engines are cheaper – ranging from $500,000 to a few million dollars per engine.
For instance, the PT6A-60a is a popular propeller engine that costs around $955,500.
In conclusion, most small planes have only one engine, but commercial and large planes normally have between 2 and 4.
Commercial planes have more engines since it allows them to fly faster, carry more passengers, and for safety purposes.
Small aircraft have fewer engines because of their size and needs.
Currently, no aircraft in the world has more than 8 engines, but some experimental aircraft have been designed with as many as 16 engines.
Aircraft engines are also generally expensive, ranging in the ten of millions of dollars, so aircraft manufacturers usually provide them to airlines in packages including other services like repair and maintenance.
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.
