Popular single-engine planes work fine with one engine, and all twin-engined aircraft must be certified to fly at least to some degree with one working engine. Modern long-haul twin-engined airliners can fly for up to six hours if an engine fails, because these planes are built to fly as well on one engine as they can on two. A single engine might keep the airplane in level flight without losing airspeed. Having just one engine operating means you will not have the maximum thrust power for takeoff, but will be able to fly and land safely.
Expert behind this article
Jim Goodrich
Jim Goodrich is a pilot, aviation expert and founder of Tsunami Air.
Can an airplane fly with one engine?
Yes, an airplane can fly with one engine. Any twin-engined commercial airplane is built so that it can depart, climb, cruise and land while one engine is shut down. Under the European EASA CS 25 rules the crew must be able to continue the take-off after decision speed V1 with one engine inoperative, and the climb gradient must still meet safety margins. The construction of these aircraft is such that, depending on weight and altitude, the live engine can keep the jet in level flight or only a shallow descent, letting the pilots return to the departure field, divert, or in some cases continue to the planned destination.
If both engines stop the aircraft does not fall but glides. Modern airliners can glide for a considerable distance, giving the crew time to find an airport or a safe field while they try to restart. Over oceans, twin-jets fly under ETOPS rules that require them to stay within a specified diversion time of a usable runway when one engine fails and the same rules govern the very rare situation in which both engines fail and the crew must glide to a landing site.
How long can a plane fly with one engine?
A plane can fly for around three to six hours with one engine. Today's twin-engine airliners carry formal permission called an ETOPS rating that states exactly how many minutes they will continue on one engine. The most common approval, ETOPS-180, equals three hours and Boeing 737-800, 737 MAX and 767 are cleared for that length, while the Airbus A330 is cleared for 240 minutes - four hours.
More capable types achieve still higher limits. The Boeing 777 and 787 have ETOPS 330, which translates to five and a half hours of single-engine cruise. One 777-300ER demonstrated this in flight by covering well over five hours from Seattle toward Taipei. The current record belongs to the Airbus A350-900; It holds ETOPS-370, giving it six hours and ten minutes aloft on one engine. In distance terms, ETOPS-370 is equivalent to 2,500 nautical miles and ETOPS-285, granted to the A330neo, to 2,000 nautical miles.
Head-winds, temperature, and aircraft weight extend or shorten these figures, so each operator must plan with enough reserve to reach a suitable airport. Modern long-haul twins can safely remain airborne for up to six hours after an engine stops, and newer designs continue to stretch that limit.
Can a plane land with one engine?
Yes, a plane can land on one engine. An aircraft landed safely on one engine at Hawaii's Kona Airport after pilots turned off one of the engines manually to make the emergency landing. Qantas pilots landed a plane with just one working engine in a separate incident.
The maneuver is demanding. Single engine landing results in an increase in the distance required to bring the aircraft to a complete stop, and flaps must be configured differently for a single engine landing so that directional control is preserved while drag is minimized. Controllers extend the runway-in-use, rescue vehicles are pre-positioned, and the crew rehearses the approach profile twice in the cockpit before actually committing which ensures the plane can still arrive safely under asymmetric thrust.
Certification standards anticipate the scenario. Because an engine can go down in the middle of a flight, every transport aircraft is demonstrated during trials to climb, cruise, and descend on a single power-plant. Because aircraft manufacturers were keen to increase the ETOPS rating of their twin-engine aircraft, the same demonstration covers diversions as long as 330 minutes.
