aerolover27
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Aircraft Tilting During Landing

Tue Oct 02, 2012 2:12 pm

hello all,

this is my first post at airliners though ive been following the forums since years.

Sorry if its a simple question..... i have observed aircrafts taking tilts before landing and mostly assumed it to be adjusting it to the runway for landing. on few occasions i have noticed severe banking on either sides continously but flying straight without change in direction, mostly observed this on emirates landing at dubai. as the view is awesome i never gave it a thought. recently while i was on a ryan air flight landing at east midlands, observed the same, i thought about this event and the reason behind it. is it to reduce speed? but y such steep risky tilts to reduce the speed and how much difference does it make? or is there any other theory behind it..... curious to hear from the pilots itself....
 
CosmicCruiser
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RE: Aircraft Tilting During Landing

Tue Oct 02, 2012 2:23 pm

crosswind landing.

filler
filler
 
aerolover27
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RE: Aircraft Tilting During Landing

Tue Oct 02, 2012 2:49 pm

sorry about my question, it is aircraft tilting before landing. the tilting or smooth banking of aircraft to left and right much before landing, maybe 15-30 mins before landing....
 
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Starlionblue
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RE: Aircraft Tilting During Landing

Tue Oct 02, 2012 2:55 pm

As CosmicCruiser says, crosswind is the cause. If there is a crosswind and you point the nose in the same direction as the runway heading, you will drift off downwind. (Same in cruise obviously). So you point the nose into the wind.

There are two basic ways to correct for crosswind on landing.
- Aileron into the wind and opposite rudder ("sideslip"). This means you are banking into the wind to drift into the wind (to oppose downwind drift) and using the rudder to align the nose with the runway. Depending on the intensity of the wind, you may touch down with the upwind main gear first. This is typically not used in airliners because the wings are low with engines under them and being in a bank on touchdown may lead to a wing and/or nacelle strike. It also feels "weird" for the passengers since you are not coordinated.
- Crab and "kick out". This is typically used by airliners. You keep the wings level and point the nose into the wind and fly "sideways" across the ground on the runway heading. Of course from the aircraft's perspective, it is flying straight through the air mass. Nice and coordinated and little risk of striking an engine. Right around touchdown, push on the appropriate rudder pedal to align with the runway. This method can also increase side loads on the gear, which is why it is more appropriate in larger aircraft.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
MGASJO
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RE: Aircraft Tilting During Landing

Tue Oct 02, 2012 2:58 pm

Quoting aerolover27 (Reply 2):

sorry about my question, it is aircraft tilting before landing. the tilting or smooth banking of aircraft to left and right much before landing, maybe 15-30 mins before landing....

You would want to align yourself to the runway if you are in visual conditions or keep your instrument approach lined if you are not in visual conditions. Winds will move the airplane around and the pilots will use the controls to align the aircraft.
If you want to reduce speed you will decrease power, use flaps, spoiler ...etc
C208B
 
vikkyvik
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RE: Aircraft Tilting During Landing

Tue Oct 02, 2012 3:44 pm

Quoting aerolover27 (Reply 2):
sorry about my question, it is aircraft tilting before landing. the tilting or smooth banking of aircraft to left and right much before landing, maybe 15-30 mins before landing....

Not sure I completely understand. You're asking why airplanes bank when close to landing?

1.) Runways aren't perfectly aligned with each other. So you can't take off, fly in a straight line, and land without ever turning.
2.) Terminal approach areas usually have specific approach paths. So you can't just fly into LAX's airspace and follow your own path to the runway. You'll either be following an arrival path (like a Standard Terminal Arrival, or STAR), or following ATC's directions. This will usually involve turning.
3.) Airliners don't often bank without changing direction. Not a whole lot of need for it, with the exception of one technique for crosswind landings as Starlionblue posted.
I'm watching Jeopardy. The category is worst Madonna songs. "This one from 1987 is terrible".
 
Viscount724
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RE: Aircraft Tilting During Landing

Tue Oct 02, 2012 11:05 pm

Quoting Starlionblue (Reply 3):
- Crab and "kick out". This is typically used by airliners. You keep the wings level and point the nose into the wind and fly "sideways" across the ground on the runway heading. Of course from the aircraft's perspective, it is flying straight through the air mass. Nice and coordinated and little risk of striking an engine. Right around touchdown, push on the appropriate rudder pedal to align with the runway. This method can also increase side loads on the gear, which is why it is more appropriate in larger aircraft.

Some examples at YUL.
http://www.youtube.com/watch?v=BFloyyEBblQ
http://www.youtube.com/watch?v=92bhD_fHlrM
http://www.youtube.com/watch?v=hRWcQ1CTOnQ
http://www.youtube.com/watch?v=27vKkz5id8w
 
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Starlionblue
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RE: Aircraft Tilting During Landing

Wed Oct 03, 2012 12:48 am

Quoting Viscount724 (Reply 6):
Some examples at YUL.
http://www.youtube.com/watch?v=BFloyyEBblQ
http://www.youtube.com/watch?v=92bhD_fHlrM
http://www.youtube.com/watch?v=hRWcQ1CTOnQ
http://www.youtube.com/watch?v=27vKk...5id8w

Nice!

Notice how they use the crab and "kick out" method but still touch down on the upwind wheel first, indicating a slight sideslip right at the end. Otherwise they would drift more on touchdown. Also the wind right at the surface may well be significantly less due to surface friction and obstacles.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
aerolover27
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RE: Aircraft Tilting During Landing

Wed Oct 03, 2012 9:47 am

my apologies in framing my question....   i meant the s-turns well before landing... i found a video on this and here goes the link....

http://www.youtube.com/watch?v=stdpRizcrjM
 
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Starlionblue
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RE: Aircraft Tilting During Landing

Wed Oct 03, 2012 10:04 am

S-turns are typically for spacing. ATC asks an aircraft to slow down because another is ahead and the spacing is too small.

You may also feel a lot of turns if the aircraft is following an arrivals procedure, meaning a defined course through the air from en-route to the runway. These are very commonly used at busy airports to ensure proper traffic flow.

The video, however, is showing S-turns in order to lose altitude for an emergency descent or to make an emergency landing site that is close by.

[Edited 2012-10-03 03:25:34]
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
aerolover27
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RE: Aircraft Tilting During Landing

Thu Oct 04, 2012 7:31 am

Thank you all for ur replies...

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