Does a 747 or any other large commerical plane need more RUNWAY to land? or more RUNWAY to take off?

Question

I understand speed and weight play a factor...I'm just looking for a general idea- under normal circumstance (ie the plane isn't going 400mph when it's trying to land)

Answer 1

mbsports is absolutely correct.

I work at LAX and a fully loaded heavy can only take off from the longest runway, 3 of the 4 runways are too short, but they can all land on any runway. I watch the planes take off (when they're airborne, that means I can go home) and sometimes it doesn't look like they'll run out of runway. When it lands it only takes half the distance.

On the other hand, some of the 747 freighters come in loaded from Asia and leave empty to pick up cargo in San Francisco or Anchorage. They have very little fuel and no cargo and use a lot less runway take off than to land.

At LAX, they use the longer runways for takeoffs and the shorter ones for landings.

If you're comparing takeoffs and landings with all things being equal, weight, wind, etc. landing are shorter.

Answer 2

If this is a question about takeoff versus landing, aircraft usually need more runway to take off than to land. You are starting out at zero ground speed. The flaps/slats on the wings are used to provide more lift to get the aircraft off the runway sooner. Then, after takeoff, the flaps/slats are stowed because when extended, they create drag as well as extra lift. So inflight, the aircraft is in a "clean" configuration allowing it to fly faster.

Landing can be done in a much shorter distance because now you have full flaps and slats extended, thrust reversers, and brakes to stop the aircraft.

One a side note, aircraft rarely use full power for takeoff. Unless the aircraft is at or close to max gross takeoff weight for a particular runway, airlines elect to use reduced thrust to save wear and tear on the engines. This thrust reduction can be small, or as great as 20%!. That is why, sometimes, it looks like a smaller jet (737 vs 747) takes up the whole runway to take off.

Answer 3

Well the airplane isnt going 400 mph when its trying to land either... but anyway...

Typically, an airplane will require more runway to take off than to land... its pretty simple really, taking 910,000 lbs. of airplane (fully loaded 747-400ER) from a dead stop to over 150 mph takes time... when this airplane is fully loaded it takes 10,137 ft. to takeoff... now, consider that when it lands it is up to 430,000 lbs. lighter than when it took off... also, it is much easier to stop an airplane than to get it going... using thrust reversers, spoilers, brakes, and the friction of the runway... I would say that most of the time, a 747 could land and stop in about 1/2 the takeoff distance... assuming you have a point in stopping it short... otherwise, it is much easier on the airplane to let it roll out and stop iteslf... less wear on the engines and the brakes... which can cost up to half a million a piece to replace...

Answer 4

Seems to me that a fully loaded plane may need more room to take off than land. After all, fuel is burned tending to lose the weight. In emergencies I would like to have more runway to land especially over obstacles approaching the landing site; the reverse is true too. If a plane needs to abort, then yeah, need more runway to take-off for safety reasons.
I'm not multi-rated but I think of those things

Answer 5

There's a host of factors to consider. Gross weight of the plane, payload, amount of fuel onboard, outside air temperature, elevation of the airport, just to name a few.

Most planes, not just the 747 or large planes in general, need more length to takeoff, as they're heavier, and lose weight during flight due to fuel being consumed.

In a nutshell, it ultimately depends on what the plane's maximum landing weight is.

Answer 6

Some good answers, but to make it all sound better, consider a car that has to accelerate to 120mph and one that has to stop from 120mph. Which one do you think will do it in less distance.

It is a general rule, not just with the 747, but with most aircraft, that the take-off run is longer than the landing distance. There are of course loads of details, but I'll spare them as many people have answered them already.

I just wanted to give you the simple, easy to undertsand answer. Hope it helps.

Answer 7

the more weight the longer the takeoff and landing is, less weight less takeoff and landing space. A 747-400 at MTOW(Maximum Takeoff Weight) needs 9902ft of runway to take off

Answer 8

I sometimes watch the aircraft take off and land at the airport near me and the distance for take off and landing seems to be roughly the same.
The standard runway length for a 747 is about 4km but they never seem to need it ; good thing too, because many airports around the world are not long enough LOL

It does vary from model to model but for a 747-100 : take off distance is 3100 metres and landing distance is 2100 metres.

Answer 9

any airplane can land on a very small runway but the questions is can it take back off? of course the anser is no. an airplane need way more take off space than its need landing space because, when an aircraft is taking off it only has the engines to make it move but when an aircraft is landing it uses reverse trust, flaps, airbrake, auto brake, and many more things to make it stop faster.

Answer 10

In general the take off speed is a bit faster. Usually they are heavier, with fuel as well as cargo and passengers. Also, they take off a bit faster to provide more of a margin for error if there's a problem during take off.