bubbers44 Re:
… The last aircraft I flew it was 29 knots because the day they certified it that was the actual wind. If the wind had been 30 knots that day, that would be the limit, that is why they call it demonstrated x-wind limit.
You assume too much. It is not necessarily true that 30kts would be the limit; the test team on another day might find that 30kts could not be demonstrated. In that case, the demonstrated value (29kt) would be moved to the limitations section of the AFM as a 'limit' (CS 25 AMC 25.158). The terms used are ‘demonstrated’ or ‘limit’, not both together.
It does not mean you can't land with a higher x-wind because the aircraft can't do it. Proper x-wind landing technique will always assure a safe approach and landing up to the limit every time.
Answers to the questions in #458 might conclude that a crew should not consider landing above any demonstrated value.
Even landings within the limit cannot be assured to be safe; consider the occurrence of a gust which might mean ‘at that critical time’ the wind is well above the demonstrated value.
The industry applies a safety margin to most parameters which if encountered in normal operation could be hazardous, e.g. approach speed / stall speed 30%, or landing distance 60%+. Then why not consider a safety margin for crosswind, which is a parameter that can result in loss of control?
cjt, crosswind values for manual landings are determined from a qualitative assessment by a test team. Normally they are judged not to be limiting nor require exceptional skill or knowledge (certification requirements).
For autoland certification, the manufacturer has to show statistically and in part by demonstration, that the landing will be safe (a high level of probability); this normally results in a lower crosswind value, which is published as a limit