Replies

I work at in Airport Operations at aa medium hub commercial airport about the same size as Midway. One of my responsibilities is that during snow/ice that I drive on the runway and conduct a friction test. The equipment we use is a computerized system developed by SAAB. It takes a continuous friction test of the entire runway. The readout is divided into 3 sections; touchdown, midfield and rollout. A numerical value is given for each section and is referred to using the Greek letter MU. Pilots take that value and use it to determine how much runway they will need to stop. Basically, the lower the MU value the longer the runway has to be for the aircraft to stop. In all the articles I have read about this incident I have not seen any reference to the airport conducting any MU tests on their runways. I have also not read anything about snow removal on the runways, how long it had been since the runway had been treated and if any previously landing aircraft relayed any breaking actions reports to ATC. Lots of info left out of this article but if it had been snowing and the airport had not conducted a friction test I would think that they were negligent.

The braking action was fair to poor with a ten knot tailwind.

The folks at Midway had pressure not to change runways because the only possible runway switch at Midway would have caused an air-traffic logjam, curtailing the use of a major departure runway at O'Hare International Airport about 20 miles away. Swapping runway operations also would have added to the serious weather-related flight delays at both airports.

From USA Today:

Pilots on a plane that had landed a few minutes before the Southwest jet reported that braking action had been fair to poor. Midway's measuring equipment had found the runway conditions were "good," Erin O'Donnell, Midway's manager, said shortly after the accident.