Maurice, I think that you have missed the point which I was making with the help of the CRFI tables, and of trying to establish a rough order of landing weight which could provide a safe landing in the reported conditions.
We don’t know exactly what the runway conditions were in this event, and it is possible that the crew did not know either.
The 6000ft runway is not grooved, and on the day it was wet, very wet, and possibly ‘flooded’ with a layer of surface water.
In very wet conditions, the maximum landing weight with similar safety margins as on a dry runway would probably be equivalent to that required to stop on a 3000ft dry runway (based on CRFI interpolation – AC 164, and speculative application to a very wet runway)
If all safety margins were discarded, then assuming a 1000ft air distance (threshold to touchdown), then the landing weight could be increased to that which would stop the aircraft in approximately 2500ft ground roll; a weight which is unlikely to be available directly from aircraft data.
This approximate distance is based on the performance analysis in the TP14842E report which states that the stopping distance on a [very] wet un-grooved runway is twice that of a dry runway. Thus for the 6000ft runway, minus 1000ft air distance, the available stopping distance is equivalent to half of the remaining 5000ft.
Will a 727 stop in this (2500ft) ground distance?
Alternatively what is the max landing weight for a 3500ft dry runway, i.e. landing on a very wet 6000ft runway with no safety margin?
Perhaps some other significant findings published in report TP14842E are:-
“It would be operationally difficult to issue accurate reports of the runway being flooded during short-term transient rainstorms”.
“During the summer months the runways are reported as “bare and dry”, damp or “bare and wet”, and rarely reported as flooded unless there is pooling of water in depressions”.
And based on interviews with airfield operations managers at two major Canadian airports: -
“… airport operators do not currently make a determination of whether water on the runway is greater than 3 mm in depth during heavy rainfall, and they do not report that the runway is flooded, rather than wet, when the depth is greater than 3 mm.”