Crosswinds

Gulfstream GVII

Eddie sez:

I will expand on this section in the future, for now I've included only the techniques from earlier Gulfstreams.

Everything here is from the references shown below, with a few comments in an alternate color.

Last revision:

20200108

Techniques

Recommended Crosswind Takeoff Techniques

Crosswinds during takeoff are easily handled, provided you obey a few steps. The price of missing these steps can be extreme.

  1. Align the airplane with the centerline of the runway. Some will argue that you should line up on the downwind side because the airplane will tend to weathervane into the wind, but if you lose a downwind engine you've reduced your margin on that side.
  2. Roll ailerons into the wind prior to brake release, but don't put in so much aileron that you raise a spoiler, which will increase drag. If you are on a short runway and need all the distance, that extra drag could be costly.
  3. As you accelerate, keep on centerline with rudder and reduce aileron to keep the wings level.
  4. Do not raise the nose until ready to rotate. You will not have enough rudder authority until Vmcg and that is computed into your rotation speed. The pilot of Gulfstream IV N23AC got this wrong.
  5. Rotate deliberately and once the airplane is definitely climbing, retract the gear and slowly relax crosswind controls and allow the airplane to crab into the wind. Make sure you keep an eye on the ground track or required departure track and adjust as necessary.

Recommended Crosswind Landing Techniques

The G450 Aircraft Operating Manual used to have a pretty good discussion of crosswind landing procedure (§06-05-10 ¶2.B.) but they took all that out. It was removed from the entire GV series. When I pointed this out, I was told it was a mistake and these procedures will be returned to the manuals.

Figures: G450 Crosswind Landings, from Gulfstream G450 Aircraft Operating Manual (Historical), §06-05-10, Figure 2.

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During the final approach phase of the crosswind landing the pilot should fly aligned with or slightly upwind of the runway center line utilizing crab into the wind sufficient to stabilize the aircraft in drift. Due to the varying crosswind components the pilot must change the amount of crab-angle as the airplane progresses down the approach path. Avoid excessive airspeeds during the approach. A prolonged float after flare will increase pilot work load during touchdown. Drift correction during touchdown is far easier when the pilot can control the timing of the touchdown.

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Approaching touchdown, the rudder is applied to align the aircraft fuselage with the runway and simultaneous opposite aileron is applied to achieve zero drift. This combination of wing down/opposite rudder will be coordinated throughout the last portion of the landing approach until touchdown.

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Touchdown with the upwind landing gear first, then set the other main wheel on the runway without delay. Utilize the rudder as needed to keep the airplane on the runway centerline. Use aileron into the wind as necessary on the initial landing to keep the upwind landing gear on the runway. Immediately on touchdown lower the nose wheel to the runway and supply sufficient forward pressure on the yoke to maintain nose wheel contact with the runway. As the roll out speed decreases, the pilot should shift directional control to nose wheel steering and normal braking. The copilot, when directed by the pilot, will take control of the yoke and maintain forward pressure and aileron into the wind. The use of thrust reversers is the pilot’s option, but be aware that in crosswinds, thrust reversers are destabilizing. Do not deploy the thrust reversers at the expense of maintaining the airplane down the runway centerline. For landings on wet or icy runways, the maximum recommended crosswind is reduced as indicated on the maximum allowable crosswind chart

This crab until the flare procedure will strike most big airplane drivers as nuts. In the Boeing 707 we could not land in a crab so we set up the wing-low early. In the Boeing 747 you had your option of landing in a crab or wing-low, but you didn't want to make any sudden changes at the last moment. So what of our Gulfstream?

It took me a few years of experimentation but I have to say the Gulfstream method works best for this airplane with a strong crosswind. Above 20 knots or so the wing-low required is appreciable, and uncomfortable.


See Also:

Gulfstream GVII-G500 Airplane Flight Manual, Revision 4, August 29, 2019

Gulfstream GVII-G500 Production Aircraft Systems, Revision 3, July 15, 2019