Why planes fly at 40000 feet?

Question

Why planes fly at 40000 feet?

Answer 1

SC, airplanes fly where the weather is to their liking. A good tail wind is worth a lot in time and money. The air is thinner at high altitudes, and the temperature is cold which makes the engines more efficient there than at lower altitudes. For most airlines a computer figures all of this out, and comes up with a flight plan which includes way points and altitude.

Regards,

Dan

Answer 2

Main reasons:

1) Better fuel efficiency

2) Avoid weather

3) Upper winds - speed bonus

Other nice reasons

4) More options in the event of an engine/dual engine failure

5) Noise abatement

6) Avoid low flying general aviation taffic

7) Avoid mountains/terrain

8) Longer radio range (for both communication and navigation)

9) Longer line of sight

Same answer from... http://ca.answers.yahoo.com/question/ind...

Answer 3

better fuel economy

Answer 4

Better fuel economy - the air up there is thinner, so it takes less gas to push through it.

Planes usually don't fly higher because then the air is too thin and then they need to spend gas to stay aloft.

Answer 5

Airliners that are able to fly at 30,000 to 40,000 feet do so because the engines burn less fuel at those altitudes to produce the required amount of power.

The engines do not produce as much power as they do at lower altitudes, but less is needed because the air is thinner and less force is needed to move the airplane at a given speed.

Also, there is less turbulence at higher altitudes under a given set of conditions, and encounters with severe weather are more rare.

Jet airliners do not use "gas" or gasoline, for fuel; the fuel is jet fuel--any of several types.

Most high altitude flights are at altitudes in the range of 30,000 to 35, 000 feet.  It is not common to fly at 40,000 feet.

Answer 6

Yeah yeah, fuel economy and all that.

But imagine what it would be like if all the air traffic was at 10,000 ft !

- noisy

- turbulent

- really busy

- dangerous

- and so on...

Answer 7

At 40,000 feet the air is thinner, the mixture must be leaned, This means less fuel in used to compensate for thinner air.

Not all plane fly at 40,000 feet. Above 18,000 is Class A airspace. In class A airspace, the planes range from 18,000 to around 46,0000. If they all flew at 40,000 they would collide. To enter this you must have an IFR flight plan. pilots with out an instrument rating can't enter class A.

If you are talking about all planes, not just commercial, most planes fly in Class E Airspace.