took off from the chicago airport for newark just after 9:00 a.m. less than an hour later the pilot diverting to cleveland. the crack on the outer windowpane not deep enough to cause depressurization inside the plane. >> this is what we call a precautionary emergency. in other words, it's not an immediate threat because there's no loss of pressurization. but anytime you have windows compromised, you want to get down as quickly as you can. >> reporter: the 737 and its passengers landing safely. just two weeks after passenger jennifer riordan was nearly sucked out of a southwest plane after an engine busted the window next to her. tonight a southwest spokeswoman saying the decision to divert today's flight was made from maintenance review of the multiple layers of a windowpane. southwest says that window was