What will happen to a plane if it runs out of fuel?

If i plane runs out of fuel and all engines fail while it is say, 39,000 feet in the sky, how would it fall?


Would it drops straight out of the sky


would it glide along for a little bit


or would it be a gradual descend?


How fast would it descend?


what would it feel like?|||Airplanes do not drop out of the sky, even if they run out of fuel. They can glide very well. In fact, if all engines run out of gas at 39,000 feet, the airliner can glide for more than 100 miles with no engine power at all.





With no power, cabin pressure will gradually decrease, since the engines provide the pressurization. If the airplane is still at high altitude, oxygen masks will drop in the cabin so that people can breathe more easily until the airplane descends more (at high altitude, there isn't much oxygen in the thin air). Once the airplane reaches a lower altitude, the masks are no longer necessary.





As for how it would feel, if you've already traveled on an airliner, you know how it feels鈥攂ecause the airliner glides down to the destination airport on every flight. When it comes time to descend during a normal flight, the engines are set to idle, and the airplane glides. This is done because it uses very little fuel. It's essentially the same way the airplane would glide if the engines were turned off, but of course in the normal case they are not shut off, they are just set to idle.





Turbulence is movement that occurs in the airplane when it moves between masses of air that are moving at different speeds or in different directions. As the airplane passes from one air mass to another, it gets jostled around by the changing wind. It really doesn't move very much (usually just a few feet), but it moves suddenly because the airplane is flying so fast. It's harmless to the airplane, but it can be dangerous to passengers who are not wearing their seat belts when the movements occur. It's a bit like riding in a car that is traveling fast over a bumpy road鈥攁nd just as in a car, it's a good idea to wear seat belts in a plane.|||It would glide all the way down. Assuming the crew knew it was out of fuel (they don't always!) they would immediately point the plane towards the nearest airport (taking into account prevailing winds). Every plane has a different glide ratio, and the crew would immediately calculate whether they could reach the nearest airport and what safety margin they had.





Cabin pressurization would be lost gradually. Emergency oxygen should provide 30 minutes for all passengers and crew. That would help avoid a tricky decision for the crew -- they may need to descend slowly to maximize their glide distance and reach the airport, but if they don't descend quickly, passengers could suffocate. Emergency oxygen would let them descend at their optimum speed (called 'best glide').





For a 747, best glide is about 250 knots (290 miles per hour). They should be able to glide about 3 miles for every thousand feet of altitude they have. At 39,000 feet, that would give them about 130 miles, descending at about 1,200 feet per minute for half an hour or so.|||lots of physics involved in that one lol. bernoullis principle is a pretty big deal in flight. lots of veriables too like the shape of the wing and the airspeed at failure. generally the plane will glide for a while, but a Boeing 747 is going to glide a lot longer than an F-4 fighter jet just because of the shape and size of the wing. also the cabin is usually pressurized by the engine or some type of auxillary power unit. pressurization isn't that big of a deal, I don't think. it's not like rapid de-pressurization is going to give you the bends. some aircraft have a seperate fuel source for the apu. sorry for the vague answers, but there are so many right answers it's hard to pick one.|||there is a mathematical formula that actually deals with this, it has to do with the weight of the airplane, and the wingspan and gravity. In order to keep the plane flying it needs to travel at least the minumum airspeed designed for this airplane by its engineers. So the pilot points the nose towards the earth, and as the plane falls it will pick up airspeed, this is good, so now are pilot is coming down, The computers on the air plane could, if needed figure out the best glide path for that airplane, so if it can glide lets say 100 miles from where it is, and there is an airport 70 miles away, thats great, you just recalculate the glide path to the airport, and follow the course the computer tells you. You are now flying the airplane towards the ground with no power. This is called a dead stick landing (no power eguals dead stick) The biggest problem the pilot now faces is that you only get one chance, to do it right, and to keep the airspeed necessary to keep the plane flying, the plane has to land at a extremely fast airspeed, far in excess of normal landings, which means among other things, you need a very long runway.


The landing is sometimes pretty hard, and on a big heavy jet it can blow out all or almost all of the tires, and sometimes destroys the suspension and landing gear of the airplane, but engineers overbuild these airplanes when engineering this helps the airplane to withstand some of the stresses of a hard landing, might do millions of dollars of damage, but the passengers get to go home in one peice.


WHICH I WOULD CONSIDER THE BEST OUTCOME.


There is a name for the formula, I think by the guy who figured it out, maybe you will get lucky and another yahoo answerer will know what its called. hoped this answer helped you out.|||1) it will glide. Just keep in mind that airliners are not designed for gliding, so it will not glide too far. According to a 747 instructor pilot, a 747 will glide 17:1. At 35000 ft it'll glide about 120 miles. Add a little more for 39000.





2) Yes, the cabin will stay pressurized. The cabin doesn't "leak" just because engine lost power.





3) It'll be falling, but not TOO hard.





4) Turbulence is "rough air", basically. Like your car shaking when a truck sped past you? That's turbulence.





5) Look up "gimli glider"





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Kasey C, PC guru since Apple II days


All generalizations are false, including this one.|||For the answers above - gliding speed of a 747 would be Vref + 70 knots -


That is he best L over D - flaps up of course -


A typical Vref being 140 knots, you would glide at 210 KIAS|||It wouild glide to the crash site.|||1. It would gradually descend as long as the pilot kept sufficient air speed to keep it from stalling (the point at which there isn't enough air moving across the wing to keep it flying)


2. The rate of decent depends on the aircraft, altitude, weight, and speed. I'm not sure of specific decent rates for different aircraft, but say it was 15:1. That would mean the aircraft would move 15 feet forward for every 1 foot it dropped.


3. You wouldn't have the sensation of falling. After the initial drop from level flight into a decent, it would be at such a shallow angle it would once again feel like level flight.


4. Most larger aircraft are equipped with an APU, or Auxiliary Power Unit. However, the APU is essentially a small jet engine, which, to my understanding, is fed from the mail fuel reserves, meaning a dry tank would render it inoperable. There are certain aircraft, such as certain Airbus models, I believe, that have an emergency APU, which is, in essence, a small windmill that can be extended from underneath the fuselage and generates a very small amount of power which can be used for cockpit lights and hydraulic controls. This, obviously, can only work while the aircraft is in motion, and would not be able to supply enough power for the pressurization system. The pressure would slowly return to the atmospheric pressure at altitude. The pilots would need to descend to a certain altitude in a certain amount of time before the entire cabin depressurized. The oxygen masks are set to deploy after the cabin pressure falls below a certain PSI, so depending on how quickly the pilots descended, it is possible oxygen would be deployed.


5. If I didn't answer it thoroughly enough in 4, cabin pressure is maintained by an air compressor which is either powered by the main engines or the APU, and pressurizes the cabin to around 8,000ft on most commercial flights above 10,000ft. Without power from the engines or APU, the generator cannot run and will consequently lose pressure.


6. Turbulence is a pocket of disturbed air. It can be caused by numerous things such as jet wash from another aircraft or atmospheric pressure changes.|||I would imagine the plane would glide for a bit until the wind resistance finally overtakes. As for how would it feel... like I'm about to sh*t myself because I'm FALLING TO MY DEATH! How else would you put that? And as for cabin pressure, there is a built in air compressor in the plane that maintains cabin pressure, and that whole system is run off of a different source of power, like an auxiliary diesel engine, so the compressor would be able to maintain cabin pressure even when the main engines fail.