Originally Posted by gonso
Mr Boeing (his lawyers to be exact), state in the FCTM that the crab that is caused by max landing crosswind component is acceptable for touchdown. Without de-crabing at all.
The FCTM also states:
If the crew elects to fly the sideslip to touchdown, it may be necessary to add a crab during strong crosswinds.
It then refers to the landing crosswind guidelines table, which includes the following note:
Sideslip only (zero crab) landings are not recommended with crosswinds in excess of 17 knots at flaps 15, 20 knots at flaps 30, or 23 knots at flaps 40. This recommendation ensures adequate ground clearance and is based on maintaining adequate control margin.
For NG's with winglets, the zero crab landing crosswinds are further reduced by 2 knots. Roughtly translated for normal conditions: do not try to fully decrab if the crosswind exceeds 20kts or you may end up damaging your flap fairing or engine nacelle. Something worth to consider, especially if you favour wing low landings.
Concerning my own landing technique, I personally prefer decrabbing during the flare. This is probably because that's the technique my instructor taught me back in my PPL days and it's suited me ever since. It is a dynamic manoeuvre alright, but very much controllable
if you apply your corrections with care. Descending through 500 feet or so (I'd say 1000 for a widebody), start aiming slightly upwind of the centerline/localizer. During the flare gently (!) apply rudder to align (or at least: start aligning) the nose parallel to the centerline, and use ailerons to arrest the drift - normally works like a charm... for me.
The 737 rudder is very effective so you really must be careful not to overcorrect. Keeping in mind Boeing's recommendations I'd rather land with the nose slightly facing to the upwind side than give too much rudder input with the nose ending up pointing downwind. Notice that if you land with a slight crab angle it is actually pretty easy to further align the nose with the centerline during the transition to nosewheel touchdown, especially if you land the nosewheel gently, like it is done by the Boeing test pilots in the first 777 landing from the videoclip mentioned by
Permafrost.
Elixir, in the end I think you need to find out what works best
for you, and that obviously requires experience. The 737 FCTM mentions de-crabbing during flare, touchdown in crab, and sideslip (wing low) techniques as valid x-wind landing techniques, but leaves room for the pilot to decide what works best. Luckily, the SOPs of my company allow some leeway too (in both meanings of the word)... although landing in crab at max. crosswind will surely raise some eyebrows.
