What causes Crosswinds when Landing?

Question

Does it also affect the taking off of the aircraft? what are the instances of having a crosswind in an airport?

Answer 1

Crosswind is a wind blowing perpendicular to an aircrafts direction of travel. So let's say a plane is on runway 36 at a given airport and he has a 20 knot wind blowing at 090 (Think compass headings): this would be a crosswind. Pilots counter crosswinds by either Crabbing, De-crabbing or Sideslipping. To save on the length of this, I've found a link that will describe these techniques to you in detail. As far as takeoffs, crosswinds don't play as much of a factor because the aircraft is on the ground during takeoff and doesn't rely on its flight characteristics to maneuver there. The pilots may have to apply additional rudder to stay on center if the wind is severe enough. Hope this helps!

Answer 2

A cross wind in nothing more than the wind flowing across the runway rather than parallel to it. So that when you are lined up with it acts as a force pushing you one side or the other. You must compensate with you rudder and ailerons to keep the aircraft lined up with the runway center line. This is important due to avoiding lateral stresses on you landing gear and loss of control. The technique is simple really. All you do is put your ailerons into the wind (full deflection at the beginning of the aircraft roll during takeoff, and decrease them as you increase speed. This will keep you from wanting to roll from the wind and keeps the tire on the up wind side planted on the ground, then as you pick up speed and the rudder becomes active due to airflow apply pressure in the way that will keep the nose centered (at this point the nose gear is doing most of the work), after the plane is airborne, you are still required to keep runway center line, so you must initiate a crab, which is the plane flying sideways (into the wind) to compensate for the cross wind.
Most of the time an Airport will have a crosswind of some kind, but all the takeoffs and landings are considered routine unless the wind exceeds the maximum demonstrated crosswind for that particular airplane.
Hope this helps.

Answer 3

Cross wind is air flowing across the runway at an angle. It can result in the aircraft going off track while approaching and landing. A lot of good answers have been provided, but I would just say that the pilots should approach for landing with the wing towards the air flow lowered and a bit of opposite rudder (to keep the aircraft straight) until touch down when both controls are neutralised.

Take offs are also affected. In this case also the aircraft is held steady on it take off roll by use of the nose wheel steering initially and then by the use of rudder when this becomes effective. Once airborne, the wing towards the wind direction is held down and once climb is established the ailerons neutralised.

Instances of cross winds depend on the weather conditions.

Answer 4

Ethereal_Slumber is mostly correct, however, while taking off the wind does affect us. Even with a slight crosswind we will hold an aileron correction into the wind. This will help prevent the upwind wing from lifting up prior to the downwind wing as the airflow over the wing becomes effective.

As was previously stated, any wind that is not straight down the runway you are using is a crosswind. It doesn't necessarily have to be from 90 degrees off the wing, just anything not directly aligned with your direction of travel.

Answer 5

Well, the cause of a crosswind is a wind direction that is not aligned with the runway, with a resulting crosswind component. As for the slip and the crab and kickout, both techniques have been around for decades, including in light aircraft. My own experience in applying corrective aileron into the wind during the takeoff run and at liftoff in light (about 15,000 pounds) to medium size (about 30,000 pounds) business jet is that, yes, it does take seemingly less aileron deflection than in a little piston prop. But I attributed this to two things: larger control surfaces and higher speeds. (In fact, in one of the jets I fly, roll spoilers operate along with the ailerons, increasing roll response.) It's also true, though, that large vertical tails contribute to weather-vane tendencies and this can be a factor when taxiing in high winds.

Answer 6

All great answers and it took me a minute to think of something to add. And I did. In large jet transports, we use a maneuver called the "kick out" when we are faced with a very strong, especially gusty crosswind. The principal is the same as mentioned above, you have to get that aileron into the wind and opposite rudder to line up with the center line in order to avoid side loads on the gear. But there are some strong crosswinds where that might put the wing perilously low to the runway. So several years back the kick out maneuver was developed to handle those situations.

Basically you fly final in a coordinated crab all the way down to just three or four feet off the runway keeping the power up. You want to be in control of exactly when you touch down. You'll be misaligned with the runway big time so you can't just put it on from there. At the last moment, you bring the throttles to idle kick in the rudder to line up and drive the upwind main gear into the deck with opposite aileron. Almost doesn't matter how strong that wind is because you'll force that gear on before you can drift at all and that wing tip will never get close to the asphault. Then its a matter of getting the other main down and quickly lower the nose wheel. Now we deploy the speed brakes and reversers but the upwind engine stays at idle reverse and we really honk it in on with the downwind reverser. This helps to keep us lined up until we are slow enough that the wind no longer affects us.

Also, unlike in smaller aircraft, we delay putting any aileron into the wind on takeoff until we rotate. In a jet aircraft that travels at relatively high speed down the runway before it finally takes off, that big tail really has an effect as it tries to weather vane the airplane into the wind. A large deflection in aileron can put a lot of downward force on that upwind landing gear. This begins to act like a pivot that the weathervaning airplane tries to pivot around making directional control even more difficult. So we wait until it's time to rotate and then apply back pressure and aileron into the wind simultaniously.

Answer 7

Airports will always have crosswinds. The wind direction changes hour to hour as the pressure areas move.
A airplane begins to fly at a lower ground speed(think safer) if it travels into the wind (directly onto the hose) on takeoff & landing. In 'the old days' the areodrome was a big square field. Therefore the areoplane could land any direction, into into the wind... Today with 10,000 ft runways made of 42in thick material, the designer must pick a direction to create his runway which will be in the correct direction most(some) of the time....

Answer 8

If that crosswind factor isn't any greater advantageous than the confirmed crosswind factor for the B757, then it would land in a crab attitude. The plane's music and undercarriage often is the only factor lined up with the runway centerline. as quickly because it touches down, the pilot can then de-crab to line up the nostril on the centerline. landing with a crab is the popular technique on a moist, slippery runway with heavy crosswinds by using fact it decreases the quantity of flow in direction of the downwind factor of the runway. landing with a crab on a dry runway is larger with a smaller crab attitude or a sideslip if attainable. factor slips would desire to be heavily used on jetliners or any plane with pods or engines decrease than miraculous the wings to avert over-banking with the intention to no longer scrape the runway with those areas of the plane.

Answer 9

interesting John B about not using aileron into the wind in large aircraft. I never thought about that, but I'll have to compare the two techniques in the learjet I fly. Thanks

Answer 10

I THINK ETHEREAL_SLUMBER HAS IT ANSWERED NICELY. THAT SHOULD ANSWER YOUR QUESTION.