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Centaurus
31st May 2006, 13:49
Some years ago a B737 FCTM recommended the control wheel should be preset (vague guess of about yea!) into the crosswind at the start of the take off roll. This reflected a long accepted technique used for crosswind take offs for many types from light aircraft to heavies. Later this recommendation was deleted from the FCTM. That seemed logical because why preset the control wheel when the aircraft is stationary especially as it was just a guess at the right position.

I would have thought that the control wheel should only be turned into wind on a crosswind take off if you sense the into wing is rising slightly and you want to ensure both main wheels are firmly in contact with the runway. In other words leave the wheel central during the take off roll until it is essential for control purposes. This minimises spoiler drag at high speeds. Any thoughts on this?

Chesty Morgan
31st May 2006, 13:58
We do this on the 146.

As my old line training captain said "It's better and easier to keep it down, than it is to get it back down if it's lifted". He's right, and it works...trust me!

Rainboe
31st May 2006, 14:48
I think I go with the presets. I division per 5 knot crosswind component, just hold it there. As you accelerate, you should start getting a broad idea of the actual crosswind strength from the amount of rudder needed. The aileron is already there when you need it, and you can start backing it off s you speed up. I think it's too late when you start to feel a wing lift- you are then fighting a correcting battle. As for spoiler drag, if it's lifted, minimal at low speeds. The spoiler's also helpful keeping that wing down. But there are many ways to skin a cat- whatever works for you! I don't think it makes an awful lot of difference, just it's untidy to have the aeroplane tipping over slightly.

BOAC
31st May 2006, 15:31
For my twopenceworth, I do it at around 80kts on a 737 - I have never had a wing lift before that! If the wind is that strong I ain't flying:)

Rivet gun
31st May 2006, 17:45
As understand it, current advice from Boeing is that you don't need to pre set the control wheel into wind at the start of the run, but use small amounts of control wheel as nesessary to keep the wings level during the run and rotation. The concern is that pre setting could lead to overcontrol. Large control wheel input can have an adverse effect on directional controlability near Vmcg due to roll spoiler drag.

(But in the Piper Cub I use full into wind aileron at the start of the take offl!)

rhovsquared
31st May 2006, 22:35
Frankly, I don't see why it would matter on a 90000lb+ aircraft...as a habit I can see myself putting in some (all of, perhaps) aileron...(I don't fly for the airlines nor am i a working pro). For controllability issues i.e overcontrol...back off the aileron control as necessary...if you can't do that why are you flying any airplane ???

Chesty Morgan
31st May 2006, 22:42
I've had a wing lift on the 146 before, scared the hell out of me, max crosswind and most of the aileron in all ready:eek: . It IS easier to keep it down initially rather than try and get it back down once it's lifted.

Definately with Rainboe on this one!:ok:

Centaurus
1st Jun 2006, 15:05
Chesty. What does the 146 manufacturer's flight crew training manual say about the advisability of pre-set aileron - or otherwise? Sometimes the manufacturer will recommend one thing but the company that operates the airline may disagree and say another - usually without measured flight test results to back up its claim.

Chesty Morgan
1st Jun 2006, 22:48
I can't recall what the manufacturer's training manual stated or the AFM. I haven't flown the old girl for a couple of years now. I think that it was company SOP though. I used to fly with guys who had over 10,000hrs on type and they used to do it so it was good enough for me.

Anybody out there got any more recent experience??

828a
2nd Jun 2006, 09:50
Cross wind take off in;
(1) Tiger Moth, hold the stick over before moving.
(2) DC3, roll the wheel over before moving.
(3) B747, roll the wheel over before moving.
They are all the same, keeping the wing down right from the start is the easiest way to ensure all goes well.
828a.

MrBernoulli
4th Jun 2006, 05:51
Yes, I have to admit to being a fan of applying some into-wind aileron at the start of the T/O roll.

As has already been alluded to above though, on the larger heavy-metal stuff it is a sensible idea to know at what yoke input your spoilers are going to crack open. Start with that angle and then do what you have to with the roll control to keep the aircraft wings level on the ground. At rotate be prepared for the weather-cock and, again, coordinate roll and yaw to keep level and track the intended direction.