Snowy Runway Suspected in Crash

Midway opened in 1927 in what was then a sparsely populated section of southwest Chicago. As the city grew, the airfield became hemmed in on all sides by development, precluding runway lengthening. The problem was exacerbated by modern, larger jets that require longer runways.

"With 6,500 feet, you don't have a lot of margin of error," said Greg Feith, a former National Transportation Safety Board accident investigator. He said investigators will want to know where the plane touched down. "You want that plane down in the first third -- or in the 'touchdown zone' -- of the runway. If you land anywhere out of that zone, you increase overrun potential," he said.

It is always the pilot's decision whether to land, but the Federal Aviation Administration and the airport monitor runway and weather conditions to provide information for pilots to use in making the decision. If weather conditions are too poor, the airport will shut down runways.

Abrams said airport crews were working constantly Thursday to remove snow and monitor runway conditions. She said that crews had conducted "friction tests" to determine how slippery the runway was about 20 minutes before the accident and that "the braking action was good."

The weather conditions at the time of the accident were nearly bad enough to make a pilot think twice about attempting a landing at Midway.

Cloud ceiling was at 300 feet and visibility was a quarter-mile, according to the NTSB. The temperature was about 27 degrees Fahrenheit and the wind was at 11 knots, which would have created a crosswind and a tail wind, aviation safety experts said, making the landing a bit more challenging.

Midway experienced a similar crash exactly 33 years earlier -- Dec. 8, 1972. A United Airlines 737 skidded off a runway and crashed into several homes beyond the airport's fences, killing 43 of 61 passengers and two people on the ground.

In 2000, a Southwest jet overshot a runway in Burbank, Calif., and stopped feet from a gas station. No one was killed, and the accident was blamed on pilot error.

The FAA has required airports to build new runways with extended buffer areas beyond the concrete in case of aircraft overrun.

Researcher Meg Smith contributed to this report.