Cracks are reported to have been discovered in three more Southwest Airlines aircraft similar to those thought to have caused another to develop a hole in its cabin roof in mid-air, according to officials.
Nineteen other Boeing 737-300s showed no problems and will return to service, according to the US National Transportation Safety Board.
The 737 with the ruptured fuselage made an emergency landing in Arizona on Friday after some of the 118 passengers reported hearing a loud bang as a 1.5m-long gash appeared after take off from Phoenix.
The hole prompted a sudden drop in cabin pressure, forcing pilots to make a controlled descent from 34,400ft to a military base. No-one was seriously injured, although a flight attendant was slightly hurt.
The US domestic low fares carrier cancelled 600 flights over the weekend to allow engineers to carry out a special test developed by Boeing on 79 aircraft. Tests on the 57 remaining Boeings are expected to be completed by the end of tomorrow. Further flight cancellations are likely until all are back in the air.
There are 931 such aircraft in service worldwide, with 288 based in the US. The airline’s chief operating officer Mike Van de Ven said: “What we saw with Flight 812 was a new and unknown issue.
“Prior to the event regarding Flight 812, we were in compliance with the FAA-mandated and Boeing-recommended structural inspection requirements for that aircraft.
“We regret any customer inconveniences as a result of the inspections currently under way. Delays and cancellations are never the preference, however we are taking every precaution we can to ensure that our operation is safe.”
Picture: BriYYZ – licensed under Creative Commons Attribution-Share Alike 2.0 Generic