Re post #199 “the other flights previous to this one landed safely”.
This assumes that all of the conditions in the accident situation are the same or sufficiently similar to the previous landings to produce the same result.
The braking performance on contaminated runways is very variable, just as 2.9mm of water (not contaminated) vs 3mm which is (but only by definition) will not protect you from an excursion, neither will accepting without question what has gone before. Hydroplaning speeds (and characteristics) vary with small and seemingly insignificant changes in conditions. In addition to the often quoted relationship between speed and tyre pressure, and factors involving a firm touchdown or the depth of water at that point, there are also factors of tyre type (material), tread pattern, and tread wear. Then add minor changes in wind direction (which could also pool water in patches on the runway), aircraft systems availability, malfunction, and crew behaviour, then you have a completely different situation.
This is a very good reason to be wary of reported braking performance from preceding aircraft (PIREPs); it only relates to that specific aircraft, that crew, in the conditions at that time.
You are in charge of your landing and only you can make the judgement about the reported conditions. Yet again the question of ‘can the aircraft land here’ must be restated as “should the aircraft be landing here”, and of course asked by a whole range of people, not just the crew who may not have sufficient information to judge – even if they might believe they have because it’s a familiar airport.
Hydroplaning Ref Aircraft Performance on Contaminated Runways. - 12 Mb