Investigators Focus on Assembly Errors in 737 Roof Failures

Assembly errors-and not metal fatigue-are now being investigated as the possible cause for dangerous fuselage delamination discovered on Boeing 737 jets operated by Southwest Airlines. Six jets with cracks were built in a similar time frame at a former Boeing plant in Wichita, KS.

A 5-foot hole appeared on Southwest Flight 812 on April 1. The original focus was the potential for microcracks that radiated from rivet holes and worsened over time. That scenario was particularly ominous because Boeing expected the aluminum fuselages to remain stable in the roof location much longer.

Investigators are exploring several possible errors during assembly in the 1990s. Focus is on the size and the way rivets and sealants were used to hold aluminum panels together. The National Transportation Safety Board is leading the investigation. Possible problems with the planes’ production were first reported by ABC News.

Electromagnetic inspections of an area of the roof called the lap joint are being conducted on other 737s.