CONF iture Re “To obey this figure, the crew knows he has, in this especially challenging environment, to proceed to a text book landing and deceleration. It provides only 250 "extra" meters …”
If you mean that there is some other approved landing technique which can improve the landing performance then you are mistaken.
A ‘text book’ landing is what should always be aimed for on every landing and it would not require any special tricks; it provides an average ‘performance’ landing. Attempting to land from a low threshold crossing height, landing ‘short’ or at low speed will inevitable break the rules and increase risk.
Re “Once airborne, the crew can eventually discard the factored distance.”
No, why should they. Factored distances are a requirement for good purpose – to maintain the required level of safety – the additions are safety factors not multiples of distance to be traded or ignored.
A wet landing distance (factored or unfactored) is based on ‘standard’ data. There are assumptions about runway friction, which in this instance appear to be much less due to recent heavy rain and/or a ‘slippery’ surface from newly laid asphalt. In addition, landing data takes account of the wind; in a tailwind this is factored by 150%. If wind measurement or assessment is incorrect, or there are sudden wind changes then the data is in error – 150% error; thus tailwind operations have greater risk.
Don’t forget that the speed estimates from the video relate to ground speed; so far there is no public information on either airspeed or wind speed, thus an apparent ‘fast’ landing could be due to either aircraft handling or wind speed.