Aircraft cracks not found in routine inspections

Southwest Airlines canceled 100 flights Monday and about 600 over the weekend to conduct inspections, following an incident Friday when a hole opened in the roof of one of the company’s Boeing 737 planes during flight and caused an emergency landing in Arizona.

Initial inspection of the plane and the 5-foot by 1-foot hole showed cracking in the plane’s skin, which the National Transportation Safety Board says would likely not be visible during routine inspections. Weekend examinations of other aircraft found found “small, subsurface cracks” or indications of cracks in three other planes.

Why are Southwest planes having this problem, and is it specific to the airline's fleet? Today on American Morning, former FAA chief of staff Michael Goldfarb talks about the Boeing 737-300 plane's maintenance track record with AM’s Ali Velshi.

Flying Southwest? The company says to check its site to see if your flight is among the canceled trips. http://www.southwest.com/html/travel_center/delays_cancellations.html

Read CNN's coverage of Friday's emergency landing here.