Takeoff with light quartering tailwind
 

What should be aileron position if you are taking off in light quareting tailwind? What i learned in CPL Days was...
for taxiing in light quartering tailwind (say from left) hold control wheel to the right so that my left ailerons are down and right ailerons are up. Does same thing hold good for takeoff also?

No. Into wind for t/o.

always into the wind.

Don't know what airplane you are flying, but beware of the fact that if you displace the yoke to far into the wind -> your spoilers will also come up -> causing more drag.

Further info
 

Referring to this webpage http://freepilotinfo.********.com/20...wind-taxi.html shows POH diagram for taxiing with tailwind. It says left quartering tailwind left aileron down. So why would it be different for takeoff?

If it is b737 what will be aileron position with light quartering tailwind?
Note: just insert word b-l-o-g-s-p-o-t in above weblink without dashes

Sure, always into the wind, why would it be different?

Once the take off run is commenced then you do not have a tailwind in any real sense. The ground speed will be higher than your airspeed, but there is not wind coming from behind, and over, the tail and wings.

Control displaced when taxiing light aircraft can be "reversed", because at that stage there may be wind coming from behind, but this is quite different.

Wally.

Thats a good way of explaining it Wally :)

True ifly, but how far is 'too far' ? If you are looking at the aileron trim markings on the yoke in front of you, how many before the spoilers rise?

Went through the trouble of checking the AMM about this a while back for the 737, If I remember correctly the spoilers start to come up at 1.6 units on the yoke. Still - this is not a reason to limit aileron inputs if they are required...

This is from a 737 FCTM. Two things stand out to me. 1/Many pilots I fly with don't start the roll with the control wheel approximately centered and increase it as it is required. And 2/ What is "excessive" control wheel displacement?

Can you tell me which model 737 FTCM you are quoting from.

Thanks

From an 800 model.

In the 727, the spoilers come up after the yoke is rotated 10 degrees. In the 747 for dummies manual I've got with me, it doesn't give a number, it just says the ailerons and spoilers work together for roll control. Hey, if it's not in the book, they can't ask about it on the oral.

In most transport airplanes you are limited to a 10 knot tailwind. You're going to change that around to a headwind before the power is even half way set.

That was the procedure taught in J3 cubs and light aircraft, not airliners. They don't get flipped over by gusts like the light stuff unless you are really stupid.

Why are you increasing control wheel displacement as airspeed increases? If this theory were to hold true than you would have a large amount of aileron deflection as they become effective, leading to worse problems than a tailwind <10 kts.

You should start with it deflected and return to neutral as the airspeed increases so that you leave the runway wings level.

I haven't flown the 727, does it have markings indicating when you've reached 10 degrees rotation?

Thats not what boeing say. I see quite a few pilots starting with it already deflected and working backwards to somewhere thats hopefully right. If you do it like the book says it works nicely, you never end up with too much aileron. Do you ease off the aileron as the airspeed increases and then during rotation change direction and increase the aileron input again in order to maintain the wings level during rotation?

Framer
I think you may have mis-read the book or are reading from the landing section where you increase aileron deflection as the speed decreases and the ailerons become less effective.

I find it hard to believe that Boeing would publish something like this. If you start at neutral and work into the wind as the airspeed increases you're trying to roll the airplane while it's still on the ground. This puts extra stresses on the landing gear and really stresses that work their way back to the wing root. Not to mention differential drag on the main landing gear causing a yaw in the direction of aileron deflection. So that takes care of the problems on the ground.

Now for the problems in the air. The ailerons work by changing the lift on the individual wings. Aileron down, increased angle of attack, more lift and vice versa. So as you get closer to Vr one wing will be making the lift required for rotation before the other. You can see where this is going. Now you have one wing flying and the other one...well...not. And since both wings are connected, with asymmetrical lift one goes up, the other goes down. And it's not long till the tip of the wing meets concrete and the insurance rate begins to climb.

The procedure for takeoff (this could be different in the bigger jets with roll spoilers and all that stuff, the biggest thing I've ever flown is a King Air) is to start with the ailerons deflected fully into the crosswind, whether it's a headwind, or tailwind, that doesn't matter, because like someone else said the tailwind is gone by the time the engine is halfway to takeoff power. As the airspeed increases you'll feel the control forces increase (hydraulic controls too? I think, dunno, never flown 'em) so you slowly "give in" to the suggestion the airplane is giving you and begin to return the control wheel to neutral. The goal should be to hit neutral just before rotation speed, pull the airplane off the runway, and adjust bank angle as appropriate.

My goodness you're authoritive for someone who has never flown the aircraft you are giving advice on.

Different machinary, different techniques required. Boeing did publish that,it is a direct cut and paste from the latest update :)

That aint gunna be pretty in a 737.

Interesting. From the Flight Crew Training Manual for the 737-200 dated in 2005, it says simply "maintain wings level during the takeoff roll by applying control wheel displacement into the wind".

An old instructor, ex RAAF - eccentric but a gifted instructor, taught that the ailerons are for roll control.

Therefore, if barrelling down the runway and the wind is not sufficient to cause any roll, leave ailerons neutral. If the wind is causing some roll (there won't be much because the darned thing's on the ground) only use enough aileron to keep wings level (ie, use the natural horizon).

Simple. :ok: