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Old 14th Mar 2016, 03:02
  #39 (permalink)  
Mach Jump
 
Join Date: May 2005
Location: Yorkshire
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I do find it interesting that we've got a lot of quite experienced people, with some very different views on something that should ideally be pretty fundamental and universally agreed.
I often find that pilots who consistently handle crosswinds without difficulty are using the same technique, but describe it differently.

Successful pilots who say that they 'kick off the drift' or 'decrab', are almost invariably using these terms to describe the process of converting, in the flare, from a crabbed approach, (flying in balance with the aircraft heading somewhat into the wind to maintain the centreline) to a side slipping touchdown, where angle of bank (aileron) maintains the aircraft on the centreline, and yaw (rudder) maintains the runway heading.

I find that if you teach this technique for all landings, then dealing with crosswinds ceases to be a problem.

... is that there's enough margin in everything to mean that it doesn't matter as much as we think - another is that gust response and control authority scale about the same (which probably is true) that they pretty much cancel each other out.
I think you're right on both these points, Genghis. If people would just stick to the speeds in the POH, they would be generally better off than making up their own.


I think he 'speed' thing is a misunderstanding in two parts. There is the gust response/control response factor on the approach, but the more important for crosswind landings, is the touchdown speed.

The faster your touchdown speed, the less the drift for a given wind.

For instance, with a crosswind of 20kt an aircraft touching down at 20kt will have a very scary drift angle of 45 degrees, whereas, another aircraft touching down at 200kt would hardly notice a 20kt crosswind at all.

It follows, therefore, that the faster you touch down in any aircraft, the less effect any crosswind will have.

The problem with landing at higher speeds, is that it requires a lower nose attitude on landing. In the old days, this wasn't a huge problem, as the tailwheel aircraft of the time simply raised their tails, and did a 'wheeler landing'.

For modern tricycle types, this isn't an option, as 'flat' landings damage nose-wheels, and cause 'wheelbarrowing'. We have all seen the results of that.

There is, however, a way of landing such aircraft at higher speeds, whilst still maintaining the same landing attitude, and that is to reduce the flap setting.

A Warrior landing without flap, but in the same lading attitude as one landing with 3 notches, will touch down around 10-15kt faster. (Remember those flapless landings you last did during your PPL?) This will reduce the drift at touchdown considerably.

Note: You don't need to increase the approach speed beyond the normal flapless speed for this, so the landing distance should be no more than for a flapless landing.


MJ

Last edited by Mach Jump; 14th Mar 2016 at 03:30.
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