Crosswind limit "alarm" on pilot display
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Crosswind limit "alarm" on pilot display
Is there anyway that a display could sound an audible alarm on an approach if the crosswind component became over either your SOP limit or the aircraft limit?
I read that in crosswind landings pilots heads are buried down on the display looking at the wind constantly - surely you are checking just for busting limits rather than a constant changing figure? If you could preset an alarm to alert you that you are now over the limit it would save the head down approach whereas a head up all the time might be more beneficial as long as you knew when the limit had been crossed.
Of course the alarm would have to be set for direction of runway and only to activate at a certain height, but would it help?
I read that in crosswind landings pilots heads are buried down on the display looking at the wind constantly - surely you are checking just for busting limits rather than a constant changing figure? If you could preset an alarm to alert you that you are now over the limit it would save the head down approach whereas a head up all the time might be more beneficial as long as you knew when the limit had been crossed.
Of course the alarm would have to be set for direction of runway and only to activate at a certain height, but would it help?
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To previous poster: Then you know nothing about windy conditions. I totally agree that an alarm would be ideal, but it would be highly impractical. As you get closer to ground, the wind will decrease. So, when should this system start to work? And what about gusts? I often see wind above limits till the last, say 2-300 feet. On the 737, I keep FMC prog page 2 open, just to have a glance before flare. But it's rarely of any use because if it's at limits you'll be quite busy and not having either guts, nor the capacity to look down.
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...and RYR-738-thingy, you yourself know too little about kalman filtering, which is involved in bringing you the display on PROG 2, and means that you are not looking at a display of instant wind, in any case, but rather a weighted average of sensed (or derived) wind computed over an unspecified period of recent time.
The ideal place to measure the wind is on the ground near the runway, and at the same time calculate the crosswind component. These should be communicated to the crew who will compare the information with the operational limits, which should also include pilot experience, currency, etc.
The problem is that wind (like runway friction) is difficult to measure in a meaningful way for operators, thus crews have to interpret whatever information is available – reported wind, ATIS, forecast, trend, synoptic chart, etc. (Generally FMS / GPS are not good indicators of actual wind, they are ‘historic’ devices, being heavily lagged.)
The report below covers the essential aspects with some very meaningful conclusions which pilots could incorporate in their personal SOPs.
This is a MUST READ document for all pilots. ‘Safety aspects of aircraft operations in crosswind.’
The problem is that wind (like runway friction) is difficult to measure in a meaningful way for operators, thus crews have to interpret whatever information is available – reported wind, ATIS, forecast, trend, synoptic chart, etc. (Generally FMS / GPS are not good indicators of actual wind, they are ‘historic’ devices, being heavily lagged.)
The report below covers the essential aspects with some very meaningful conclusions which pilots could incorporate in their personal SOPs.
This is a MUST READ document for all pilots. ‘Safety aspects of aircraft operations in crosswind.’
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I'm pleased to see meneer van Es' work being given this worthwhile plaudit; those searching for 'bullet points' should consider the difference between 'surface wind' (standard ICAO two minute average with gusts) and 'instant wind', read straight from (one hopes) an appropriately-sited 10m anemometer.
However, in global terms, there's no point in discussing these niceties until operators decide whether gusts count or not. It's good aircraft design, good handling skills, and good fortune, that keep catastrophe at bay in gusting crosswinds at present.
However, in global terms, there's no point in discussing these niceties until operators decide whether gusts count or not. It's good aircraft design, good handling skills, and good fortune, that keep catastrophe at bay in gusting crosswinds at present.
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Very hard to be precise when measuring x-wind. Generally taking the last tower reported wind and comparing it in context with the ATIS and forecast is the best practise.
To get a precise wind readout at the touchdown zone at the precise moment the wheels touch the ground would really only serve useful for the nasty b&st%rd lawyer out to sue the pilot.
If the pilot is happy that the wind is within his/her aircraft limitations and his/her own capabilities and then flys an approach the best and most useful information then is a drift assesment combined with handling familiarity on that aircraft. Knowing how much rudder and aileron to apply in the flare to lead to success. I don't think an actual wind readout during the flare or just prior to the flare is as useful as pilot judgement.
To get a precise wind readout at the touchdown zone at the precise moment the wheels touch the ground would really only serve useful for the nasty b&st%rd lawyer out to sue the pilot.
If the pilot is happy that the wind is within his/her aircraft limitations and his/her own capabilities and then flys an approach the best and most useful information then is a drift assesment combined with handling familiarity on that aircraft. Knowing how much rudder and aileron to apply in the flare to lead to success. I don't think an actual wind readout during the flare or just prior to the flare is as useful as pilot judgement.
