Wondering if a plane can fly if the worst were to happen and all engines? This post shares everything you need to know!
What happens if all engines fail in the air?
If both engines fail, the aircraft will fly and glide quite happily. Modern passenger jets can glide with a ratio of around 1:10, so for every 1000 feet lost, the aircraft will fly 10,000 feet forward.
Thankfully modern passenger jets are incredibly reliable, and the chances of having an engine failure are extremely rare. The chances of having a total loss of thrust on all engines are extremely improbable.
There have been a few cases where all engines have failed on an aircraft. The main reason for all engines failing is typically:
- Fuel starvation
- Bird strike causing double engine failure
- Inadvertently entering an area where volcanic ash is present
Air Transat A330 fuel starvation
After finding a fuel imbalance, an Air Transat A330 from Toronto to Lisbon diverted into Lajes Airport (LPLA), Terceira Island in the Azores. An engine change occurred previously, and incorrect installation led to fuel pipes rupturing.
The first the crew came to know of a problem was via a fuel imbalance indication in the flight deck. From memory, the crew executed the fuel imbalance checklist failing to recognise they had a fuel leak.
The high workload in trying to resolve the fuel imbalance meant that the crew failed to recognise that more fuel was being lost through trying to balance the fuel.
Eventually, both engines flamed out when all the fuel was lost. The flight crews excellent skill meant that once the engines had flamed out, they did a fantastic job executing a dead stick landing in the Azores.
Everyone survived the incident.
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US Airways flight 1549 birdstrike caused all engines to fail
US Airways flight 1549 suffered a double engine failure soon after take off from New York after hitting a flock of geese. The bird strike occurred just below 3000ft, leaving the crew little time to attempt an engine relight.
With attempted engine relights failing to restart the engines, quick thinking from the crew and excellent handling skills allowed them to land in the Hudson River. Everyone managed to get out of the aircraft after the ditching.
British airway flight 009
On the 24th June 1982, a British Airways 747-200 inadvertently entered volcanic ash over Indonesia. Volcanic ash deposits clogged up the engines as deposits melted onto engine turbine blades.
The symptoms of volcanic ash start with high-temperature indications and possible surging of the engines. Eventually, the engines flame out, and the engines fail. In the descent that followed, the 747 crew were able to relight each of their engines and carry out a diversion.
One of the secondary effects of flying through the volcanic ash cloud was that the forward-facing flight deck windows were effectively sandblasted, so the crew had limited visibility looking forward. They used the side windows and flew an instrument approach to judge when to flare.
What happens if both engines fail in flight?
If the engines were to fail during the cruise, then relatively speaking, the flight crew would have a reasonable amount of time to attempt a relight. The crew would first start the non-normal checklist for loss of thrust on both engines to try and restart the engines.
If the engines fail close to the ground, the options are limited. The crew will, in all likelihood, try and restart the engines but will very quickly turn their attention to finding a safe landing location.
Most jet aircraft have an auxiliary power unit (APU). The APU allows electrical power to be supplied if both engines fail. The APU also provides bleed air, which can pressurise the hydraulic system in the event of a total loss of the engine-driven hydraulic pumps.
The critical thing is that even if both engines fail in flight, basic flight control can be maintained in roll, pitch and yaw to allow the aircraft to glide and hopefully execute an inflight restart.
In a piston aircraft, failure of both engines with no possibility to restart generally means finding a suitable location to carry out a forced landing.
Most piston aircraft have batteries on board to provide some electrical power, and flight control forces are usually sufficiently light as not to need complex hydraulic systems.
It is worth noting that during descending phases of flight, when the thrust levers closed or engines at a low thrust setting, the plane is effectively acting as a glider in that it is not producing enough thrust to fly on its own. It is reliant on converting height to airspeed.
Can a plane fly with no engine?
Planes can fly with no engines, provided they have sufficient height and speed to glide.
How far can a plane fly with no engine?
Passenger jets have a glide ratio of 1:10, so from a cruise altitude of 36000ft, a passenger jet can glide for approximately 120km.
Gliders can have a glide ratio as high as 1:30 or sometimes more, allowing them to cover 300km – 500km distances comfortably provided they can find thermals, ridge or wave lift to top up their height along the way.
Can a 747 take-off with 2 engines?
A 747, unless pretty empty on modified, will not take off with two engines. The 747, subject to weight restrictions, can take off with three engines and is used as a test best for developing new aeroplane engines.
Using the 747 as a test best for new aircraft engines allows the new engine to be tested in the air and offers the reliability of having three good engines and not relying on the test engine to generate thrust.
The 747 could fly on two engines if it did suffer a double engine failure provided performance-wise, weight and altitude constraints allowed.
How common is engine failure on planes?
Engine failures on passenger planes are thankfully infrequent. The chances of having an engine failure are less than one in every one million flights. Despite practising engine failures during their six monthly checks, most pilots will go through their whole career without ever experiencing an engine failure.
If you have any questions on if a plane can fly if all engines have failed, please leave a comment in the section below.
Kudzi Chikohora is a B737 pilot with over 2,500 hours of flying in Europe. He holds a Master’s degree in Aerospace Engineering, is a chartered engineer, and is a member of the Royal Aeronautical Society.
Kudzi completed his pilot training via the self-funded modular pilot training route and created kcthepilot.com to share pilot training and aviation content.