aerolover27 From UK - England, joined May 2012, 16 posts, RR: 0 Posted (7 months 3 weeks 3 days 9 hours ago) and read 3159 times:
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 From United States of America, joined Feb 2005, 2214 posts, RR: 16 Reply 1, posted (7 months 3 weeks 3 days 9 hours ago) and read 3135 times:
aerolover27 From UK - England, joined May 2012, 16 posts, RR: 0 Reply 2, posted (7 months 3 weeks 3 days 9 hours ago) and read 3106 times:
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....
Starlionblue From Hong Kong, joined Feb 2004, 15872 posts, RR: 66 Reply 3, posted (7 months 3 weeks 3 days 9 hours ago) and read 3103 times:
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." - from Citadel by John Ringo
MGASJO From Nicaragua, joined Feb 2005, 449 posts, RR: 8 Reply 4, posted (7 months 3 weeks 3 days 8 hours ago) and read 3097 times:
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
vikkyvik From United States of America, joined Jul 2003, 8225 posts, RR: 28 Reply 5, posted (7 months 3 weeks 3 days 8 hours ago) and read 3052 times:
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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.
"Two and a Half Men" was filmed in front of a live ostrich.
Viscount724 From Switzerland, joined Oct 2006, 21495 posts, RR: 24 Reply 6, posted (7 months 3 weeks 3 days ago) and read 2802 times:
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.
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." - from Citadel by John Ringo
Starlionblue From Hong Kong, joined Feb 2004, 15872 posts, RR: 66 Reply 9, posted (7 months 3 weeks 2 days 13 hours ago) and read 2605 times:
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." - from Citadel by John Ringo
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From UK - England, joined May 2012, 16 posts, 
From United States of America, joined Feb 2005, 2214 posts, 
From Hong Kong, joined Feb 2004, 15872 posts, 
From Nicaragua, joined Feb 2005, 449 posts, 
From Switzerland, joined Oct 2006, 21495 posts, 
i meant the s-turns well before landing... i found a video on this and here goes the link....
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