Southwest Airlines says that it has finished inspections of most of its 737-300’s and will be back at full operating capacity on Tuesday. The safety inspections followed an incident last Friday in which a hole in the fuselage of a Southwest 737-300 ripped open mid-flight. The plane made an emergency landing at a Marine Corp Air Station in Yuma, Arizona, on its way to Sacramento from Phoenix.

Late Monday Southwest announced it had completed inspections on 64 of the 79 planes that are being examined. Safety inspectors are looking for subsurface cracking, which at this point is believed to be the cause of Friday’s incident. So far, 3 Southwest planes have been found to have subsurface cracks, they will be grounded until repaired.

Since last Friday, hundreds of Southwest Airlines flights have been cancelled. 70 were cancelled today. Southwest is asking travelers to check the status of their flights by calling or visiting their site,

The Federal Aviation Administration (FAA) has said it plans to issue an emergency directive tomorrow. The directive will require electromagnetic inspections on older model 737’s for fatigue damage. The directive is expected to affect 175 aircraft worldwide, 80 of which are US registered.