Slipping the big jets

[BigginHillBoy]

The little I know about jets is that slipping them, e.g. during decent, is prohibited. I guess the sweepback wing is more prone to stalling (plus structural limitations come into play).

My question is what happens during heavy cross wind takeoffs? The technique applied there by pilots is slipping, right?

[Sciolistes]

Always some crossed controls for a crosswind takeoff, does not have to be particuarly strong.

Sometimes decide to do wing down landings too.

[hetfield]

Always some crossed controls for a crosswind takeoff, does not have to be particuarly strong.

Not on the Bus.

[bubbers44]

Primarily the side slip is used during landing during a crosswind on big jets just like light aircraft to avoid side loads on the main landing gear. Aerodynamically the side slip is the same as a forward slip. The point of reference of your ground track is the only difference. Being a swept wing the downwind wing will lose some lift.

[2 Whites 2 Reds]

For take off's regardless of x-wind component (below the aircraft x-wind limitation) I roll the control column into wind as necessary and use the rudder to keep it on the centre line. Once airborne centre the rudder and use ailerons only. ie cross controlling on the take off roll until Vr.

Try and get hold of a Boeing FCTM. It gives a detailes explanation of the "Boeing" method for correct X-Wind Take Off and Landing technique.

Hope this helps.

2W2R

[A37575]

For take off's regardless of x-wind component (below the aircraft x-wind limitation) I roll the control column into wind as necessary

From the 737 FCTM re crosswind take off's:

"Limit control wheel input to that required to keep the wings level. Use of excessive control wheel may cause spoilers to rise which has the effect of reducing tail clearance. Large control wheel inputs can have an adverse effect on directional control near V1 (MCG) due to the additional drag of extended spoilers"

The amount of control wheel deflection often varies with pilot personal technique and unnecessarily excessive deflection throughout the take off roll can invalidate V1 because of spoiler drag at high speed and increase the take off distance

[JammedStab]

I used to slip the 727 on final(wing down method) in a crosswind as allowed by the AFM. Works well up to a certain crosswind amount depending on the weight, as given in our manuals. Then a crab(or combination) is required. 737 was slipped as well.

As for the big sideslips like you might have done in a light aircraft in order to lose height on final approach, I have only heard of a 767 doing that once. This was an emergency in Gimli, Canada where it had run out of fuel in 1982 and was landing on a relatively short runway. Apparantly a very large sideslip was done on short final(whichworked) in order to land near the beginning of the runway.

[bubbers44]

The side slip for landing put the forward slip to lose altitude without gaining airspeed in the same maneuver with a different ground reference. I never did it but forward slipping a 727 or any other aircraft wouldn't have bothered me a bit. Never needed it. I heard of a 737 crew that used it very effectively to touch down where they wanted. Good job. It lets you descend with no increase in airspeed.Period.

[misd-agin]

Limitations section, search 'sideslip' = no information available.

These aren't Cessna's and the generic handling section of the AFM covers the basics of flying the a/c. Read the section a month ago and don't recall saying anything about sideslips being prohibited.

Good idea? In general no. Prohibited? No.

[Romeo E.T.]

a small value of slip is possible without any structural damage. and on many occasions is actually done accidentally, ie in an engine failure scenario, before the right amount of rudder input or rudder trim has been applied, where directional control is still more under control of the ailerons, than trimmed off with rudder, there is a definite amount of slip taking place .

also even when trimmed out perfectly with rudder, in the engine out flight, and a dramatic power change takes place, with a slow or intially non existant rudder counteract but an aileron application was applied to stop the secondary effect of roll, then there is again a large slip that takes place until "balanced" flight is re-attained with rudder/rudder trim.

all of this occurs without structural damage, otherwise we would be hearing of a lot more incidents/accidents of vertical stab seperation and or engine pylon seperation every time there is an engine failure.