Why does a landing plane appear to be moving slowly? When it could easily drop out of the sky.?

Answer 1

The reason aircraft may appear to be moving slowly when approaching for a landing is due to a combination of things. First, an aircraft on final approach is moving relatively slowly (compared to its cruising speed), with attitude (pitch) and power set to maintain an appropriate glideslope to the runway, at a speed typically 1.3 x stall speed, thereby allowing the aircraft to slow in the flare (the last phase of landing, very close to the ground) and decelerate to stall speed, or slightly above, at touchdown. The aircraft is fully under control, and nowhere near to "falling out of the sky." Approach (and stall) speeds vary with the type of aircraft, its weight and configuration (flap positions, landing gear, angle of bank, if any, etc.). Second, especially from the ground, an aircraft may appear to be going slower than it actually is due to a combination of aircraft size, your distance from the aircraft, and the lack of fixed reference points behind your visual target (the aircraft), thereby reducing the visual sensation of speed. This is quite noticeable as aircraft size increases - I once watched a flight of two C-5A Galaxies (then the largest flying aircraft in the world) fly over me at an altitude of about 500 feet AGL (I was on the ground at the time), and it looked as though they were barely crawling, despite the fact that they were both traveling at least 250 knots, probably much more.

BTW, just to correct a possible misunderstanding of some information previously presented in an answer, trimmed for approach speed, the airplane is NOT falling out of the air, and level or climbing flight is easily attained at approach speed, with application of more power. In fact, the procedure for a go-around (aborted landing) is to increase power, attain Vx (best angle of climb speed) or Vy (best rate of climb speed), as necessary, and clean up the airplane (retract landing gear, raise flaps) after attaining a positive rate of climb and adequate airspeed for the configuration changes, all of which are generally below typical approach speeds. Effectively, power controls climb or descent, pitch (nose up or down) controls airspeed. There is a more complex interaction, but that is the primary rule in low speed operation of an aircraft.

Answer 2

Airplanes can't drop out of the sky unless a wing breaks off or they lose airspeed too quickly.

Airplane wings are straight on the bottom and curved over the top edge. As the plane moves forward it 'cuts' the air at the front edge of the wing, some air goes under and some air goes over top of the wing just like if you stick your hand out the window. The air going across the bottom of the wing goes from point A (front of wing) to point B (rear of wing) fast because a straight line is the quickest way from Point A to Point B. The air going across the top travels faster because it has to follow the curve. This creates "lift". The more lift created the more the wings can lift. Either have more curve in the wing or go faster, and the plane stays in the air.

Even if a plane is slowing down to land it is still going fast enough to have enough lift to fly in the air. If you are standing to the side of a landing plane then you see it slowing down little by little. If you are watching a plane coming to you straight then the closer it gets the slower it appears to be going. This is only an illusion due to the size of the plane and your position to its flight.

Answer 3

It actually IS dropping out of the sky, but at a controlled rate. (approx 3 degrees glideslope) The aircraft is actually trimmed to fly at a speed that is not high enough to keep the aircraft in the air!
When aircraft are approaching landing, the objective is to touch down at the slowest possible ground speed so you can use shorter runways.
But if you go too slow, you stall....how does this work?
Aircraft typically employ flaps and slats on the wing to increase the lift available from the wing. When these are deployed, it allows the aircraft to fly a lot slower and still have the same amount of lift.
Why don't they always use the flaps? They cause a lot of drag and are only best used in the landing (and sometimes takeoff) situations.

Answer 4

When coming in for landing, A plane flies in what pilots know as the "ground effect". Its considered a "Venturi" in which air must squeeze through a smaller space (between the wing and the ground), thus creating higher pressure below the wing, generating more lift.

If the aircraft were at the same speed a couple hundred feet off the ground, it would be incapable of maintaining airborne becuase of the absence of the ground effect.

Pilots also deploy full flaps upon landing to increase wing area, and surface area. This generates more lift at slower speeds, and creates more dynamic pressure.

Because of the aircrafts size, it will always appear to be flying entirely too slow to maintain flight. Weird stuff.

Answer 5

One of the reasons it appears to move slowly is the lack of nonmoving ground objects your eye can look at while it's tracking the airplane. Another reason is due to the size of the airplane. When the C5 or 747 comes in for a landing, they almost appear to be floating, but they are still clipping along. If they have a stiff headwind, their ground speed can be reduced a bit due to increased airspeed from the wind.

Answer 6

Every aircraft has an approach speed is necessary to maintain for a safe landing. Approach speeds vary for types of aircraft. What I think you are seeing is the optical illusion of slowness that is brought about by being far away from the aircraft. If you could get closer to the appraoch end of the airport, you'd actually see that the aircarft on approach is moving very fast.

Answer 7

It appears so slow because...to your eye...it is going that slow. Since you are so used to seeing them going so fast... when they are on approach for landing, the difference in speed is great and you eye just "superimposes" that slowness to make it seem slower. That's what I think.....and I concocted that because my neighbor's family came down and they never see planes and when they were here (just outside of Boston, MA) they were like LOOK HOW FAST THAT PLANE IS GOING! And the rest of us were like yeah...fast.... So I think it has to do with an optical illusion type thing. But...thats what I think.

Answer 8

Drop out of the sky? I believe that is the whole concept behind landing.

Answer 9

Well, pretty much. I understand what you mean. When you really think about it, it's a little mind boggling. But these theories, "captain", seem to be very correct, and seem to be making a lot of sense over the many years of aircraft engineering

Answer 10

I imagine it has something to do with the lift it gets from air passing under the wings. It may be going slow but there is still air pressure keeping it up. Then again who knows.