Why do aircraft dip wings left and right when landing?

Seifer

I tried googling it but maybe my terminology is off. Can anyone explain why during the final approach for landing commercial planes seem to dip their wings right and left as they slow down?

bkehoe

If you mean like the pictures in this article then reading it should explain in detail - http://en.wikipedia.org/wiki/Flap_(aircraft)

Seifer

I don't see anything in the pictures indicating what I'm describing. Although maybe this explains it from the flaps during landing section:

Wiki wrote:

Winds across the line of flight, known as crosswinds, cause the windward side of the aircraft to generate more lift and drag, causing the aircraft to roll, yaw and pitch off its intended flight path, and as a result many light aircraft have limits on how strong the crosswind can be while using flaps

So the pilot is just fighting to keep the plane level and the dipping left and right is not intentional?

Locker10a

Seifer wrote: »

I tried googling it but maybe my terminology is off. Can anyone explain why during the final approach for landing commercial planes seem to dip their wings right and left as they slow down?

Do you mean banking ? In order for a plane to turn right or left one wing must dip if turning right the right wing will dip same for the left. this is a bank(turn) to the right/left, It is done as the plane must line up with the direction of the runway for final approach.

if you meant alot of small dips where the wing goes up and down multiple times in a minute as if the plane was wobbling side to side this is just cross winds !

Locker10a

http://www.youtube.com/watch?v=YkPgalYvGB8


Is this what you mean? The wing on final approach ?

tippilot

Because it's easier to dip the wing than move the runway.

Xpro

Crosswind maybe? Deflect the wing into the wind

Seifer

Locker10a wrote: »

Do you mean banking ? In order for a plane to turn right or left one wing must dip if turning right the right wing will dip same for the left. this is a bank(turn) to the right/left, It is done as the plane must line up with the direction of the runway for final approach.

No, I don't mean banking. It happens when the pilot is aligned on the final approach.

if you meant alot of small dips where the wing goes up and down multiple times in a minute as if the plane was wobbling side to side this is just cross winds !

This sounds more like what I've seen. It probably is just a reaction to crosswinds as I can't find any articles on it being part of any procedure.

Seifer

tippilot wrote: »

Because it's easier to dip the wing than move the runway.

Kinda surprised this jackass comment got some thanks. Trying to keep the flying club small is it?

Simon Gruber Says

It's usually the pilot/autopilot making small corrections to line up with the centreline of the runway on final approach. The aeroplane may drift a few metres either side due to wind or turbulence from windshear as you near the ground. Also a gust of wind may raise one wing and this will be corrected.

Aeoplanes tend to rock like that in the wind in full landing config with flaps and landing gear extended as the increased drag reduces stability, whilst maintaining slow flight for landing.

skyflyer

If you're talking about the wing physically bending during the flight, this is called 'Wing Flex'. Large aircraft wings are built to have the capacity to flex and bend to a certain degree during flight because of the physical forces acting on them. This is totally normal and nothing to be alarmed about. Think of it like getting a sheet of paper and waving it gently up and down. It bends and wobbles. The same sort of thing happens to wings... just on a larger scale.

Hope this helps.

Seifer

skyflyer wrote: »

If you're talking about the wing physically bending during the flight, this is called 'Wing Flex'. Large aircraft wings are built to have the capacity to flex and bend to a certain degree during flight because of the physical forces acting on them. This is totally normal and nothing to be alarmed about. Think of it like getting a sheet of paper and waving it gently up and down. It bends and wobbles. The same sort of thing happens to wings... just on a larger scale.

Hope this helps.

No, I didn't mean that. I meant actual dipping of the wings such that when the right wing dips the left wing rises and then vice versa.

skyflyer

Seifer wrote: »

No, I didn't mean that. I meant actual dipping of the wings such that when the right wing dips the left wing rises and then vice versa.

Then that was explained by several people above. The aircraft is banking to stay aligned with the runway on final approach.

Gareth2011

Yes like there is only so many things wings do when in flight. wing flex, bank, flaps, yaw (rudder) up and down (elevator). As mentioned before id say its when the plane is banking if the plane is going right and your sitting on the left of the plane your seat will go up and you will lean to the right and vice a versa.

xflyer

tippilot wrote: »

Because it's easier to dip the wing than move the runway.

Tippilot wasn't being smart. That's the simple truth. The wind rarely lines up perfectly with the runway. So there are constant adjustments to keep it lined up even if the autopilot is flying.

Seifer

xflyer wrote: »

Tippilot wasn't being smart. That's the simple truth. The wind rarely lines up perfectly with the runway. So there are constant adjustments to keep it lined up even if the autopilot is flying.

No, he wasn't being smart or clever or intelligent.
Obviously the wing dipping is required for a successful landing but by asking the question one could assume I was looking for more information than that. Which I kindly received from other posters able to grasp that simple fact.

Tenger

Gareth2011 wrote: »

......As mentioned before id say its when the plane is banking if the plane is going right and your sitting on the left of the plane your seat will go up and you will lean to the right and vice a versa.

The OP isn't talking about banking, he is referring to final approach and the adjustments the PIC makes on the approach.

@Seifer: the 'wing dipping' is the aircraft fine tuning its angle of approach to the runway. As Tippilot says the aicraft must line up to the runway.

pclancy

Seifer wrote: »

Kinda surprised this jackass comment got some thanks. Trying to keep the flying club small is it?

Ah he was joking i'm sure but he's correct, its just the aircraft keeping lined up with the runway and dealing with winds etc.

Others did explain well but a real good way to learn more would be grab a trial flight from your local aeroclub, get the controls in your hands and youi'll understand very quickly why you see the wings go up and down as the instructor explains the principles of flight. Warning: you may become addicted and throw thousands of euros at your new hobby

Or grab a copy of Microsoft Flight Simulator, great way to learn more about flying without leaving your chair.