A Mexicana Airlines Airbus A320 aircraft overran a runway at Chicago's O'Hare International Airport (ORD) on July 18, 2008, just after 7PM local time. According to the airline, the aircraft, operating as Mexicana Flight MXA802 from Mexico City, had 138 passengers and 7 crew members on board. News reports say that one flight attendant was injured and was taken to the hospital. The flight attendant's injuries are said to be "not life-threatening."
Many news reports have stated that the aircraft "overshot the runway," but, technically speaking, this is not true. The aircraft apparently landed on ORD runway 22L, but then overran the end of the runway and was stopped by the runway's arrestor bed. At the time of the overrun incident, the weather was reported to be rainy, with strong and gusty crosswinds. It is not known at this time if the weather played a causal role in the incident.
Passengers evacuated through an aft door of the aircraft, and descended to the runway via a stair truck. They were transferred from the runway to the terminal by bus.
This incident illustrates the value of arrestor beds at the end of runways. Arrestor beds have been installed just recently at both Chicago Midway Airport and O'Hare International Airport. The arrestor beds, officially known as Engineered Material Arresting Systems (EMAS), are areas of crushable material -- usually a mixture of water, foam and concrete -- beyond the threshold of a runway. The material is designed to crush under the weight of an aircraft, absorbing energy and gradually reducing the airplane's forward momentum until it stops, similar in concept to runaway truck ramps.