armchairpilot
I just want to personally dis-agree with those calculations. Simply because we are not talking about a crew that knew what would happen and would therefore take immediate action. But instead a "human" crew who needed valuable seconds to decipher what was happening to any extent and to take any action (ie stomp on brakes).
Look at it from another perspective :
First
1/- The airplane landed at CGH on runway 35L.
That runway is 1940m long and the LDA - landing distance available - is 1880m.
The METAR reports at 1720 was :340/08 6000m RA BKN 900 ft OVC 7000 ft Temps 16 / 14 QNH 1018 hPa
2/- Some pilots noticed standing water on the runway, which wasn't grooved.
We can then assume that, according to :
- the published METAR
- The Pilot Report
- the noise of the windshield wiper on the CVR,
the runway was at least wet, very probably contaminated.
Now let's just take -again - the A320 QRH that gives us the required *in-flight* performance of the type :
At a landing weight of 62 tons, the required landing distances are :
for dry runway : 1490 m
for wet runway : 1690 m
for 3 to 6 mm of standing water : 2130 m
Those are the baseline figures for sea level and OAT < 40° C,
without reversers and without auto brakes.
Congonhas being 2600 ft above sea level, a correction of 3% per thousand feet applies for a wet runway, and 4% for 3 to 6 mm of standing water.
The resulting landing distances then became :
for a wet runway : 1690 x 107.5% =
1822 m
for standing water :2130 x 110.5% =
2354 m
Considering the built-in margins in these performances computations, you'll have to answer two questions :
- Should the airplane have been dispatched to CGH, considering the weather, the state of the runway conditions with an inop T/R ?
- Would a 2,400 m runway been enough for them to stop ?(Considering that above-average skills are not required to achieve those performances )