The aircraft's nose landing gear slipped during the last phase of the breaking procedure. The collapsible concrete, or arrestor bed, at the end of the runway was still under construction, but fortunately most of the work was done. That soft barrier is designed to crumble and bring the plane to a stop when it overshoots the runway. That is exactly what happened even though work was not complete.
This is the first time that collapsible barrier has been put to the test. It was recommended after a 2005 Southwest Airlines flight overshot the runway at Midway and crashed onto the street, killing a 6-year-old boy.
The O'Hare Runway 22L was temporarily closed. Delays averaged about 45 minutes.
Mexicana Airlines spokesman Adolfo Crespo says the Airbus A320 departed from Mexico City. Crespo says crosswinds forced Flight 802's nose gear off the runway.
As of Saturday night, investigators had not determined what caused the breaks to fail.
Crespo says the airline operates 15 daily flights into O'Hare.
The Associated Press contributed to this report.