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Home > Air Safety > What happens when all engines failed in the air?
What happens when all engines failed in the air?
Aviation - Air Safety
Wednesday, 12 December 2007 22:12

Dear Captain Lim,

If an airplane encounters all engines failures during the flight, what will happen? Does the plane start flipping and crash, or it continues to fly while losing height, and how long does it last and how safe is to land?

Raid Asfour,

Hi Raid,

This is a very interesting question and I am sure many other non-aviators would be interested.

When all engines are failed during flight, not all hopes are lost my friend ! Have you ever heard of gliders flying ? Well, gliders fly without any engines! Okay, I am being too simplistic. Nevertheless, all aircraft can glide to a safe landing but the degree of distance flown varies. Gliders can stay in the air for a long time. Single engine aircraft encountering an engine failure can also glide a fair distance to execute a safe landing provided it has the height.

I am sure your question concern commercial aircraft. Firstly, I must say that all commercial aircraft engines are very reliable and to have all the two, three or four engines failed totally on them are very, very remote. (See my article on How Safe is Flying?). Of course, I am not going to argue with the Murphy's Law that, anything that can go wrong will go wrong.

Okay, I will tell you a true story or two. In 1983, a Boeing 767 belonging to a major Airline in Canada actually lost all their (only two!) engines in flight. The cause of the failure was not because the engines were technically faulty. It was due to human error ! You see, apparently the engineer in charge of refueling the aircraft interpreted the fuel request incorrectly. The pilot requested fuel uplift in kilograms, which is normal (rather than in gallons or liters) but the refueler read it as in pounds. Remember, one kilogram of fuel equals to about 2.2 pounds. So the aircraft had about half the fuel required to fly the distance. Consequently, the Boeing 767 ran out of fuel halfway and both the engines quitted on them !

Of course, the pilots should have realized the mistake but it was unfortunate that they missed the second chain of events which could have prevented the accident. What was fortunate was that, the pilot concerned used to fly gliders as a hobby. He happened to recognize a disused airfield nearby that he used to land before. He then executed a perfect forced landing without any loss of lives or aircraft.

The second story concern another major Airline from the United Kingdom. Its Boeing 747 was enroute from London to somewhere in Australia when it lost 4 engines due to volcanic ash spewing over the sky near Jakarta in Indonesia. Fortunately, the crew were able to restart (or relight in aviation term for jet engines) at least 2 engines when they were cleared of the volcanic ash at a very low level.

Your question was, when an airplane encounters all engines failure, does the plane start flipping and crash, or continue to fly while losing height? If it continues to fly, how long does it last and how safe it is to land the aircraft ?

As I have described earlier, the aircraft does not flip or crash. It continues to fly at an optimum gliding speed, a speed much lower than its cruising speed.

However, it may not be able to maintain its cruising altitude but continues to lose height at a rate of about 3500 to 4500 feet per minute. This will give an aircraft, cruising at 35,000 feet about 10 minutes to fly a distance of about 40 to 50 nautical miles. Remember, pilots have been trained to restart/relight the engines whenever they encounter total engine failures. If restarting the engines were unsuccessful, they would have no choice but to carry out a prepared forced landing - just like what the Canadian pilot did to the crippled Boeing 767.

If you were a passenger on board this ill-fated aircraft, how would it feel like ? Although I have never encounter such an experience as a passenger, I have practiced this exercise many times and have been tested thoroughly in the aircraft simulator.

This is what will likely happen if you are in the passenger cabin. Firstly, if both engines failed simultaneously (very, very unlikely, but normally one after another), the noise level will drop very rapidly. The cabin lights will flicker and may be a bit dimmer. If the aircraft auxiliary power unit (something like a standby generator-cum compressor) fail to start automatically, you will feel the slow depressurization in your ears. Oxygen masks will drop from the ceiling and an automatic emergency announcement will be made through the Public Address System shortly. The cabin crew will then brief you the emergency procedures for a possible Forced Landing or Ditching.

How safe is it to land ? In a Boeing 777, with both engines failed, it is still controllable even though most of the normal hydraulic system pressures would be lost. However, there is the emergency hydraulic pressures generated by the Ram Air Turbine system (RAT). The RAT will automatically extend when it senses both engines had failed. There are fan blades on the RAT which will turn to generate hydraulic and electric power as the aircraft glide forward at a speed of about 180 to 280 mph. The landing gears would be extended by the emergency alternate system and the aircraft has sufficient brake pressure to bring the aircraft to a complete stop using the emergency accumulator pressure.

In a nutshell, if an airplane encounter all engines failures, it is capable of gliding to a safe landing provided there is a suitable landing area. The landing gears would extend and the brake would still function to stop the aircraft safely. So all hopes are not lost !

Hope that answers your question.

Both Engines of a Boeing 737-300 flamed out.

On the 16th of January 2002, a Boeing 737-300 belonging to an Indonesian Airline had both its engines flamed out - a term to describe that the jet engines had failed. It happened as it commenced its descend to 9000 feet through thunderous clouds that were filled with rain.

The crew then tried to relight the engines but it failed to revive. Compared to a Boeing 777 where the relighting process is automatic, the Boeing 737 did not appear to have this more advanced facility. In addition to this, on a Boeing 777, the APU will automatically light up as well when it senses both engine failures. The APU or the auxiliary power unit is a small jet engine that is located in the tail section and powers the electricity and air-conditioning of the airplane.

When the engine failed, the Captain maneuvered the airplane so that it could glide at an optimum speed of around 240 knots. This would cause the airplane to lose height rapidly at about 3000 feet per minute. He then attempted to make a forced landing, but preferred to ditch into water if only he could locate the sea. As the sea was out of reach, he decided to ditch on a river instead.

During the forced landing process, the Captain tried to decelerate from 240 to 150 knots by use of the flaps, but the hydraulics were not available to power the action. (In a Boeing 777, there is an emergency device known as a RAT or Ram Air Turbine, which is powered by free airflow as the airplane glide down with dead engines. The RAT will provide some hydraulics as well as electrical power during this very critical phase of the emergency.) Luckily, the ditching was very well flown and the Boeing 737 came to a stop, floating near the side of the river.

This was one of the very rare situations where a commercial airplane lost both engines and was able to ditch successfully. So Murphy Law is right! Engineers were unable to determine the exact cause of the failure yet but it was speculated that engine icing was one of the possible cause of the flame out. (In this accident, 23 people were injured in the plane carrying 54 passengers and a crew of 6. One stewardess died when she was drowned in the river.

US Airways emergency landing at Hudson River


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Comments (15)

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Aircraft engine failure in flight
Dear Captain Lee,

I am totally satisfied with the answer you have given to a question raised by Mr Raid Asfour-Australia "what happens if all engine fails while an aircraft is in flight." You seem to be an experience pilot. May I know if you are still in service and how many flying years you have. I admire Pilots cause that was my dream when I was a school going boy of 12 years.
Vijay S , 07 Jun, 2012
In light of the current problems with batteries being experienced with the Boeing 787 Dreamliner - which has no hydraulics - I am wondering if you know whether the Dreamliner is equipped with an electrical generator equivalent to the Ram Air Turbine system (RAT) you described for getting emergency hydraulics when the engines fail in flight.
RH , 18 Jan, 2013
Whether the B787 has a RAT deployment capability?
Please see answer here http://tinyurl.com/a2next5
Captain Lim , 19 Jan, 2013
... , Low-rated comment [Show]
Is all engines in the flight need to be operational when flying

I am Harish from India an engineering student. I have a big question than if a flight has two engines, is it necessary to run both of the engines??

Harish kumar , 19 Mar, 2014
ukraine ato
mh17 air ram and depressurization &
mh17 - air ram , 30 Jul, 2014
Engine failure
Hello, is it possible that a plane with 2 turbines and has only one engine failure, but it still can fly?
Zher Xian , 18 Oct, 2014
Yes the aircraft can fly to a certain time (may be to the closest landing point/airport). this is called as ETOPS.
Vinod , 24 Dec, 2014
Both engine fail on 737NG
Hi, can I ask in the case of loss of both engines on the 737NG, would you also loose hydraulic pressure for the controls? Would that result in manual reversion? Thank You.
Akbar , 23 Apr, 2015
decision call out and radio callout
what is radio call out
what is decision call out
prashant , 11 Aug, 2015
After reading about a recent Russian II-18 Defense Ministry plane that crashed with 7 survivors out of 32 passengers and 7 crew members, near Tiksi village, I thought maybe a parachute system would save lives but after some research seen that would not work on a large aircraft, so from there I am left with one last idea of Axillary emergency engines to save lives is that possible? Or is it to much added weight for the aircraft to handle, maybe another engine added on each wing or one in the tail section, and would it be to costly for passengers to pay for fare.
Roland Smith , 20 Dec, 2016
The luckiest ditching
Can't forget what I consider to be the luckiest ditching ever. TACA 110, where a one eyed South American pilot in a basically brand new 733 or 34 ditched on the levee in New Orleans. Both engines flamed out in a hailstorm bad enough to beat the dogs___ out of the fuselage and paint job, he was going to ditch in the river but shot for the levee at the last second and made a successful forced landing on NASA property. No fatalities, amazingly enough, they were able to swap one engine and the other still ran well enough that they could actually fly the aircraft out of there (none of this sawing the winds off business). The aircraft survived (albiet in need of repairs) and so did everyone on board.
David , 17 Jan, 2017
can be stop airplane in the sky? . yes . no
mansoor , 20 Mar, 2017
Very interesting article. A question: what is it called when a jet aircraft is put into a rapid descent in order to restart engines when all else fails? Air start?

I worked for TWA for 20 years as cabin crew. A pilot friend told me a story of an event that happened back in the 70's when we were both flying. At the time, there was some turmoil among the pilot group because a ruling had just come down that allowed pilots, who were then forced to retire at age 60, to return as flight engineers until they turned 65 (maybe even 70 - can't recall).

Airlines were still regulated, the economy was bad (airline economy especially so), no one was hiring pilots. TWA and PanAm were especially hurting. TWA did not hire a new pilot for about ten years - late 1969 - 1979 - after deregulation.

So there was some resentment among junior pilots who had been laid off and working pilots who were not moving up the seniority list. The extent of the resentment was reflected in the acronym ROPE (Rotten Old Pilot Engineers) that was applied to these captains turned flight engineers.

One of these ROPES, according to the story, was working one of his early flights as engineer on a 747. (Keep in mind that my friend, who was one of those who was frustrated over being stuck in place on the seniority list, had a decided anti-ROPE bias.)

In any event, the old but inexperienced engineer accidentally shut off fuel flow to all four engines in the process of transferring fuel between tanks at cruise. All engines flamed out and could not be restarted by conventional means.

"They dropped five miles," is how I recall my friend phrasing it, before the captain put the airplane into a dive and relit the engines via air flow.

In retirement, I am writing fiction. I am currently 200 pages into my third book ('Strangers on a Plane') - the first to draw on my airline experiences. I am using the above incident in the book. Just want to get my facts straight and my terminology correct. Thanks in advance.
Ross Retterer , 20 Jun, 2017
from my understanding, I'm pretty sure that every commercial airplane has a RAT, but only the larger ones have fuel jettison (Fuel dumping capability)
Hydraulics can be run from the electricity generated by the APU, this can sometimes be seen when flying with easyJet, when boarding/disembarking the control surfaces are usually still pressurised. It can also be heard, the hydraulics are really loud. On airbus aircraft, the option to do this is from the hydraulics panel, there is a guarded switch for running them off power.
WH , 04 Nov, 2017

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