Quote:
Originally Posted by noel
Just a brief comment on that Lufthansa A340 crosswind landing. First of all, great footage and nice to see the skill of their crew in action.
One of my family members seemed to think that variable engine thrusts would have been used to combat crosswinds like that. I begged to differ and claimed that a 'crabbing' technique was likely used. Any CPL+ rated aviators want to shed some light on this? I'm unaware that variable engine thrust is used in any procedure and seems like it would just create a host of problems with asymmetric thrust. In winds like that it would seem that crabbing is the preferred technique and it appeared to be what he did.
Thoughts CP?
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No, differential thrust is not used in a cross wind landing, it serves no purpose in that case. Typically the autothrottles are off below 100' and the flying pilot is running the thrust, so they can make rapid changes if needed during the flare.
As for types of x-wind landing techniques q-scout, they have basically been covered here; slip (most common), last second kick, crab on, and combination technique (some slip, some crab). You don't use different techniques at different airports specifically, but based on different aircraft and conditions.
A canadair rj has low wing tips, so very little bank can be in or else they will strike the runway. So last second kick is more common on that.
The 737 can do slip up to approx. 20 kts of direct x wind ( depending on flap setting ) before there is a risk of contact wing tips, engine fairings, or flap track fairings.
On a dry runway landing crab on is more uncomfortable as it straightens out more aggressively. On a wet runway it is quite comfortable as it straightens out more slowly.
On a low visibility approach, landing crab on is more desirable as inputting slip is destabilizing (as you bank you change the lift vector, the slip increases drag, all as you are flaring in unstable air).
My point is there are several issues that are weighed when deciding what technique to use. Having said that, most of the time in average winds it is a slip that will be used on most aircraft, and certainly on 737s.
I hope that all wasn't too confusing, just trying to illustrate some of the factors that we are considering when landing.