Concrete Runways and Rain

Two recent Phenom overruns have an interesting variable in common: both occurred landing on a wet, concrete, ungrooved runway.  Ungrooved concrete runways represent less than one in five of all paved runways in the US, but can be particularly treacherous when wet.

The graphic below comes from a nearly 50 year old study conducted by NASA.  The aircraft in question had a higher touchdown speed than would be common for a business jet, but its absence of speedbrakes, spoilers, or reverse thrust, and the fact it has a single main wheel on each assembly compare to many light jets.  Notice the massive difference in stopping distance required on an ungrooved concrete runway, versus a grooved asphalt runway.

Taking into account that brakes were not engaged until approximately 1700' from the runway threshold, the ground roll portion of a landing on wet ungrooved concrete was 250%-290% that of a dry surface (depending on surface texture of the concrete, as represented by surface "A" and "D" above).  A wet, grooved, asphalt surface, in contrast, required only 3% more stopping surface than a dry runway.