109
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, ...
- 1,602
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:
...
- 24k
45
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 the ...
- 230k
43
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, ...
- 52.9k
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, ...
- 33.2k
32
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 ...
- 6,732
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, ...
- 14k
30
votes
Accepted
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 ...
- 4,640
29
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:
...
- 71.8k
29
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 ...
- 14k
26
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 ...
- 230k
24
votes
Accepted
Why are trailing edge flaps used for landing?
Flaps increase the stalling lift coefficient of a wing. They can also change the angle of attack for a given lift coefficient.
By allowing the wing to operate at a higher lift coefficient without ...
- 7,329
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 ...
- 126k
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 ...
21
votes
Which one of these flaps is used on take off and land?
Jet airliners almost exclusively use slotted Fowler flaps as trailing-edge high lift devices, most of them single- or double-slotted, some even triple-slotted.
For takeoff, these are only partially ...
- 54.3k
20
votes
Accepted
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 ...
- 6,974
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 ...
- 39.2k
19
votes
Why aren't takeoff flaps used all the way up to cruise altitude?
This is a good question, and I don't feel the other answers get at the essential part which is:
Is it optimal to climb with the flaps deployed?
As with any optimal question, the answer relies on what ...
- 4,974
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 ...
- 230k
18
votes
Accepted
What does "speed checked" mean?
Because there is a maximum deployment speed for things like flaps, gear extension (and sometimes retraction). Exceeding these speeds and using those devices can cause damage to control surfaces or ...
- 36k
17
votes
Which one of these flaps is used on take off and land?
There seems to be a misconception in the question. Different aircraft have different flap systems, which are those depicted. But it's not like an aircraft has all those types of flaps and chooses some ...
- 2,070
16
votes
Accepted
How can you tell what position the flaps are in whilst on a commercial aircraft?
If you are seated behind the wings, but close, you can usually see black markings (thick line and a number) near the inboard side of the engine pylon which indicate their extension. Some might not be ...
- 8,541
16
votes
Accepted
Why does stall speed decrease when flaps are deployed?
Your stall speed decreases because the $C_{L_{MAX}}$ of the wing increases with flaps deflected.
Deploying flaps increases wing camber and increases both $C_L$ and $C_D$ at the same AoA and airspeed. ...
- 61.3k
15
votes
Why don't aircraft use gimbaled engines instead of flaps?
Historically, flaps and control surfaces were moved manually: The pilot would move a stick, a control column or pedals, and pulleys or pushrods would transfer this force to the control surfaces. To do ...
- 230k
14
votes
Accepted
What are these "lines" on the A319 flaps, are they damaged?
You are seeing the steel reinforcing sheet metal at the line where the spoilers rest on the flaps when both are retracted. It is there as a bearing surface since there is some inevitable contact ...
- 655
14
votes
Accepted
How do flap track guides work?
There are different ways of moving flaps. The trivial case where they rotate around a hinge point which lies within the airfoil contour does not increase wing area. Fowler-type, backward-moving flaps ...
- 230k
14
votes
Accepted
Do negative flaps increase glide ratio?
The flaps on a glider wing are mainly for shifting the laminar bucket of the wing to the right lift coefficient. Yes, they help to increase maximum lift, too, but for gliding this is less relevant.
...
- 230k
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