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108 votes

Is this plane landing or departing?

The plane is probably taking off. The flaps are hard to see but they don't quite look to be extended enough for landing (Looks like flaps 20). On a 747 they extend to around 45 degrees (flaps 30, ...
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  • 1,592
49 votes

Is this plane landing or departing?

Please skip to the edit after the picture to see my actual answer. I'm leaving my original answer intact though, since other answers have referenced it. I'm guessing that's it's taking off because: ...
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  • 23.6k
45 votes

Why are heavy flaps better than just a bigger wing?

When flaps are retracted they do nothing, which is the whole point. The byproduct of lift is drag, a larger wing will create more lift, but more drag as well. More drag equals a slower cruising speed, ...
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41 votes
Accepted

Is an Airbus A319 allowed to fly with a missing flap track fairing?

Fully permitted according to this Configuration Deviation List for the A320: One fairing may be partly or completely missing. There are more posts about this occurring. As Noah Krasser points out, ...
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40 votes
Accepted

Why didn't the Concorde have flaps or slats?

Why no flaps? Flaps change the pitching moment of a wing. After all, they add lift over the full chord, so the sum of the increased lift attacks at about mid-chord, which is a quarter chord aft of ...
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31 votes

Why retract flaps at go-around?

For the same reason that you don't takeoff with full flaps. Because the climb performance sucks. Flaps do add lift, but also a lot of drag. A low flap setting often provides more lift than drag, ...
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  • 13.1k
31 votes

Why aren't takeoff flaps used all the way up to cruise altitude?

The image below from this answer shows characteristics of airfoils with flaps. As you rightfully concluded, lift ($C_{L_{max}}$) goes up with the deployment of flaps, but the drag also goes up and ...
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  • 6,103
30 votes
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What happens to Cessna electric flaps that are moving when power is lost?

Stays where it is. The mechanism is a leadscrew and like most leadscrews it's "self-locking", which means that it's held in position by frictional forces whenever the motor isn't turning and it can't ...
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  • 4,561
29 votes
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If flaps are used on takeoff, when should they be retracted?

The short answer is, it depends. The FAA Airplane Flying Handbook merely states that this can be performed once the aircraft has established positive climb, but does not specify exactly when. ...
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  • 2,862
28 votes

Is this plane landing or departing?

This picture is most likely taken during landing. The flaps configuration is the best clue. Flaps are extended more for landing than they are for takeoff. Compare with other pictures of Air Force One: ...
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  • 69.7k
28 votes

Why not always take off with 10 degree flaps in a Cessna 172?

Flaps out will reduce the ground run, but you're forgetting that they also increase drag. This is why you don't climb all the way to cruise altitude with flap extended. A 172 will climb better without ...
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  • 13.1k
27 votes
Accepted

Why are heavy flaps better than just a bigger wing?

Your concerns about heavy flaps are well founded. The designers try to get away with as few high-lift devices as they can afford to. But not fewer! If you observe the trend over the years, flaps ...
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26 votes

Why and when to use flaps?

Flaps change the camber of the wing's airfoil. This in turn changes the zero-lift angle of attack, increases the maximum lift potential and, in case of fowler-type flaps, the wing's area. Airliners ...
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23 votes
Accepted

Is it possible to takeoff without flaps extended?

Yes take-off without flaps is possible. The Airbus A300 and Boeing 767 are approved for such take-offs and it is being done regularly. It results in a better climb gradient, especially with one engine ...
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  • 74.2k
22 votes
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Why did Cessna get rid of manual flaps in their 172?

Nobody can definitively answer this for you except Cessna's 1965/1966 engineering team (the year they made the change), but there are two reasons I can think of: Because switches are cooler than ...
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  • 67.2k
22 votes
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Why do slats deploy first?

The slats help to protect the outer wing from stalling when the flaps deploy. The outer wing carries the ailerons, so there are no flaps, but the flaps inboard will induce more lift on the whole wing, ...
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22 votes

Is it right to extend flaps only in the white arc?

Yes you must slow down to the white arc, or whatever your flap extension speed is for a given condition, regardless. If you are 10kts above the white arc and drop flaps anyway, it's not going to make ...
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  • 104k
21 votes
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Can a super land without flaps/spoilers?

Even the largest commercial airliners are able to land without flaps, since flap failures do happen occasionally. See a report here where an A380 landed with no flaps. This was at the Auckland, New ...
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  • 69.7k
21 votes

Is this plane landing or departing?

Measured directly on the image, the angle between the cheatline and the runway is 5.5°; the true pitch angle of the plane will be slightly less than that, because of a little perspective ...
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20 votes
Accepted

Why are flaps retracted when an aircraft is parked on ground?

A few different reasons: Good pilots put the aircraft into a well-known (up) configuration after landing, so that the aircraft is ready for use on the next flight. Flaps down during taxi was a signal ...
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  • 16.4k
20 votes
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To flap or not to flap?

You don't say which variant you're flying, but the C42B is perfectly capable of both taking off and landing with zero flaps on a reasonable-length runway. I've done it on several occasions with huge ...
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  • 6,904
19 votes

Why and when to use flaps?

Flaps increase lift and drag by changing the camber of the airfoil, and allow lower airspeeds. There is also an effect of shifting the center of pressure (C of P) aft. There may be an immediate ...
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  • 538
19 votes
Accepted

When does a 'flaps/slats misconfiguration' warning sound during takeoff roll?

For the Boeing 727-100 and 747-100/200 the answers are: when does the system know when to sound the alarm? When the thrust levers are advanced to begin the takeoff, if flaps and slats and a few ...
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  • 38.7k
18 votes

Can a super land without flaps/spoilers?

Specific information can be difficult to come by, and each airline may have their own guidance on the subject. I wasn't able to find anything for the 787, but for the according to one 777 crew ...
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  • 719
18 votes

If flaps are used on takeoff, when should they be retracted?

Below is sample screen of a Boeing 777's Primary Flight Display. See those flaps marks on the speed tape? Here's the thing: you don't want to retract the flaps from 5 to 1 when you're slower than the ...
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  • 39.2k
18 votes

Do flaps have a maximum speed limit but spoilers don't? Why?

Spoilers are used to shed energy when the aircraft is too fast or too high. That means they need to be used when the aircraft is flying fast and are designed accordingly. On the other hand flaps are ...
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  • 54.1k
18 votes
Accepted

Do auto-flaps exist?

It can be much simpler than that. The aerobatic glider Mü-28 has a symmetric airfoil with 20% flaps, and those flaps are automatically set as a function of the g-load experienced near the center of ...
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