how many engines does an aircraft have?(commercial flight). suppose if engine failure on sky, how its manage?

Answer 1

The first commercial passenger jets had 4 engines (Boing 707). These engines had two serious flaws, low relative power and high failure rates. this is to be expected in a technology that is emerging from WW II.

As engine technology got better, MTBF (mean time between failures) went up and the power to weight ratio of the engines got better, the FAA and the aircraft engineers started to reduce the engine count, the rational was that the odds of a single engine failure on an aircraft, while rare, could be handled through pilot trainning and the increased power of the remaining engines.

The Boeing 747 was the last airliner to be built that the FAA insisted that it be equipped with 4 engines as redunancy in the machine was quite high.

In large aircraft safety demands that the aircraft be controllable under the most severe operating conditions (high weight takeoffs) so 4 engines are requires. However up until just recently, an aircraft design could not get approval to fly over large bodies of water with out multiple redundancy (4 engines), jet engine MTBF rate being SO long now that the risk is worth taking.

Now, they are allowing two engine aircraft to fly world wide over limited ocean bodies. But as you can see by the A-340 the Europeans still were requiring 4 engines but some of that was due to high take off weights.

Of course the newest A-380 (555 passengers) would not garner too much credibility if it were to debut with only say three engines. Most people would take a LONG wait and see on its ability to handle high take off weights. The four engines it does sport are QUITE the dandies in the power department. I cannot find ANY info on the relative Power to Weight ratio of the A-380 and the Boing 747-800 but I am sure that the A-380 has increased it sustantially.

Right after the introduction of the Boeing 767, (dubbed the Pac Man airplane because it was flown by digital controls) a Delta flight from San Dieago took off to an altitude of some 12,000 feet and lost power to BOTH engines (uh-pilot to the chief, this aircraft only HAS 2 engines, get my drift) The pilot fought the craft all the way down to some 3,000 feet, flying it like a lead safe, and managed to get the instructions manual out in time only to find out he had turned off the fuel supply to BOTH engines inadvertantly.

He recovered his error and the engines spooled up and lit off just in time to clear the deck at 2000 ft.

They landed anyway as the lavatories were all filled up.
http://query.nytimes.com/gst/fullpage.html?res=9B0DE0DF163DF930A35754C0A961948260

Answer 2

Most commercial aircraft are classified in "performance group A". This means they have at least two engines (maybe more) and can (in theory) suffer an engine failure at ANY stage of flight without it resulting in an accident.

If an engine fails in flight the aircraft can continue to the nearest suitable airport and land safely. If the failure occurs at high altitude the aircraft will drift down to a lower altitude when it only has one operating engine, but the flight will always be planned so that in the event of engine failure, the drift down will remain clear of mountains.

The other interesting thing about performance A aircraft is that they can always cope with an engine failure during take off, either by stopping in the remaining runway distance or by continuing the take off on the remaining engine(s). Which action to take depends on the speed at which the engine failure occurs.

Answer 3

At least two. Jet engines have become so reliable that two-engined aircraft have long been certified for over-water flights. The aircraft can proceed on one engine quite nicely if there's an engine failure.

I'm not sure, but I don't believe there's ever been a case of all engines failing on an airliner over the ocean, necessitating ditching the aircraft in the water. They do carry life rafts for that contingency, however.

Answer 4

Depends on the aircraft, most have 2 engines and some have 4. If there's an engine failure on one engine, any licenced pilot is trained to fly with just a single engine on one wing and do an emergency landing at a nearby airport, failure to both engines is extremely rare scenario and it'll probably crashland due to the inability to fly the plane.

Answer 5

4 Engine Passenger Jets

Answer 6

All commercial planes are designed to keep flying just fine with one engine out. Even as far back as WW II, the 2 and 4 engine planes could continue with one engine out. The 4 engine B-17 could fly just fine on 3, and even limp along on 2.

Answer 7

You're all wrong. Take the number of engines you can see, and then add one or two - to account for the APU jet engines (s) in the rear of the plane.

I even had a test engineer at an aeronautical firm tell me this is wrong and that turbines run on gasoline since gas-turbine can't possibly mean expanding hot gases from the extremely high compression combustion, basic principle of turbine engine operation.

Check for yourself.

Answer 8

I think 2 for most planes. Some have more.. If one fails, they make an emergency landing, hopefully at a nearby AIRPORT, not like grass, and try to fly with the other engine(s.)

Answer 9

Some have 2 (MD80's, 737)
Some have 3 (DC10/MD11, 727)
Some have 4 (DC8, 747)
Most all newer planes are designed to be able to fly and land on one engine.
(QUESTION: How far can this plane we're on fly with the one engine left?
ANSWER: I'm pretty sure we'll make it all the way to the crash site!)

Answer 10

Depends on what kind of plane. Small puddle jumpers have 2 and regional jet have two. Cross country have 3-4 and international have 4,6 and 8