Fast Freeze, Not Fowl, Broke Windshield on John Wayne Jet

It wasn’t a bird that cracked the windshield of a Northwest Airlines jet, forcing it to return to John Wayne Airport the day after Christmas, officials said Tuesday. Instead, mechanics have determined that the glass became brittle from rapid exposure to cold air during ascent.

Airline officials had attributed the incident to a collision with a bird minutes after Flight 116, bound for Minneapolis-St. Paul, took off from John Wayne. No one was injured, and passengers were placed on other flights.

“The windshield was heated up by a defroster on the inside, and it was cold on the outside,” Northwest Airlines spokeswoman Christy Clapp said. “Glass becomes more brittle when it goes from hot to cold real fast. This happens about once a week in our fleet during the winter, and the other airlines have similar problems.”

Clapp said only the outermost of several windshield layers was damaged: “The inner layers are much stronger, so there was very little danger. The landing was only precautionary.”