Add 5 Kts for X-Wind Landing??
Join Date: Jul 2005
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Only time I can think of for a reduced flap setting for landing is for a S/E approach and G/A etc, having said that, the 757 I fly is certificated for flap25 and flap30 landings as part of our Ops manual
Piontyend. If you are correct in the +5 knots being solely because of GA performance, I would be surprised. If that was so, then Boeing would publish a caution on go-arounds from a bounced landing because of degradation of performance in the GA manoeuvre - and they don't. The +5 knots to Vref in light wind conditions is there (as far as I am aware anyway) to allow for the reduction in IAS due to wind gradient from the free stream flow that starts to diminish below 2000 ft above the ground. While it is common to see crews flaring at Vref plus half the HW component, this is not what is published in the various FCTM and as A37575 stated in an earlier reply, it can cause a unneeded float. And long floats can result in the danger of a tail strike.
Cloud Cutter. The object of the crosswind landing (as with most landings) is to touchdown with minimum float. Certainly in a Boeing there is no requirement to reduce flap setting simply because of a crosswind.
The additional speed with any reduced flap in an airliner or a C150 will make stuff-all reduced drift angle change and extra float only means more control juggling at a critical time as the speed drops off in the float.
At the max crosswind limit in Cessna singles and most twins, full flap should be acceptable as it involves less float and thus less exposure to sudden gusts. There is no shortage of accident reports where pilots of light aircraft have been adding knots for mum and the kids along with reduced flap settings and have finally over-run the available runway.
Cloud Cutter. The object of the crosswind landing (as with most landings) is to touchdown with minimum float. Certainly in a Boeing there is no requirement to reduce flap setting simply because of a crosswind.
The additional speed with any reduced flap in an airliner or a C150 will make stuff-all reduced drift angle change and extra float only means more control juggling at a critical time as the speed drops off in the float.
At the max crosswind limit in Cessna singles and most twins, full flap should be acceptable as it involves less float and thus less exposure to sudden gusts. There is no shortage of accident reports where pilots of light aircraft have been adding knots for mum and the kids along with reduced flap settings and have finally over-run the available runway.
Join Date: Feb 2004
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I agree completely. I was just outlining a common perception. In fact it was standard proceedure a the school where I trained to do crosswind landings with reduced flap settings. I disagree with this practice for the reasons you've given.
The only time I've used reduced flap is when introducing a student to crosswind circuits - a flapless aproach provides more time (due to increased float) for a student to sort out the control inputs required. It is purely for demonstration purposes, and I normally only throw in one or two of these part way through the lesson. Otherwise it's full flap.
I certainly wasn't suggesting that pilots of large aircraft would consider this technique.
The only time I've used reduced flap is when introducing a student to crosswind circuits - a flapless aproach provides more time (due to increased float) for a student to sort out the control inputs required. It is purely for demonstration purposes, and I normally only throw in one or two of these part way through the lesson. Otherwise it's full flap.
I certainly wasn't suggesting that pilots of large aircraft would consider this technique.
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Might be a little late on this post but....
Just got back from sitting my OZ ATPL and in the Systems/Aerody exam casa seemed to think that you add half the the headwind to you Vref up to a max of Vref + 15 and then on top of that half your gust to a max of Vref + 20. eg.
W 100/20G30 = 10 + 5 = Vref + 15
But thats only CASA.....
Just got back from sitting my OZ ATPL and in the Systems/Aerody exam casa seemed to think that you add half the the headwind to you Vref up to a max of Vref + 15 and then on top of that half your gust to a max of Vref + 20. eg.
W 100/20G30 = 10 + 5 = Vref + 15
But thats only CASA.....
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I am definitely no expert in flying jets as im still doing upgrade training but what I have learnt so far is that in swept wings lift= speed, and in a xwind condition where there is a blanketing of the wing, a little extra speed can be a good thing.
If you end up even slightly below Vapp (yes im an Airbus driver too) this can have a significant effect on the flare, or more specifically the lack of arresting the descent rate in the flare. The swept wings are that critical in their speed.
I think every one whom has landed in Taipei will agree, if due to shear you end up at Vapp-5 you will have a very firm landing, so to bug up 5kts will give a form of protection. In my case my trainer laughed all the way to the gate, apparently he guessed correctly some miles out that I was going to bury it due to not having adjusted my Vapp.
If you end up even slightly below Vapp (yes im an Airbus driver too) this can have a significant effect on the flare, or more specifically the lack of arresting the descent rate in the flare. The swept wings are that critical in their speed.
I think every one whom has landed in Taipei will agree, if due to shear you end up at Vapp-5 you will have a very firm landing, so to bug up 5kts will give a form of protection. In my case my trainer laughed all the way to the gate, apparently he guessed correctly some miles out that I was going to bury it due to not having adjusted my Vapp.
