YUMA, Ariz. — Inspectors have found small, subsurface cracks in three more Southwest Airlines planes that are similar to the cracks that caused a jetliner to lose pressure and make an emergency landing in Arizona, the airline said Sunday.
The planes will be evaluated further and more repairs will be undertaken before they are returned to service, Southwest said. The damage was not discovered during routine maintenance and probably wouldn’t have been unless mechanics had specifically looked for it, officials said.
Southwest canceled about 300 flights for the second day in a row Sunday as it inspected 79 planes in its fleet similar to the one in Friday’s incident. By Sunday afternoon, 19 planes had been returned to service, the airline said.



