An investigation is under way into why a 300mm (1ft) hole appeared in the upper fuselage of a Southwest Airlines Boeing 737-300, causing it to depressurise.
The aircraft, which was en route from Nashville to Baltimore-Washington, diverted to Yeager airport near Charleston, West Virginia following the 13 July incident. None of the 126 passengers and five crew members was injured in the event, which occurred around 30min into the service and prompted deployment of oxygen masks.
© Steve Hall
Initial crew reports, says the carrier, indicate that the incident is related to a "small-sized hole located approximately mid-cabin", near the top of the aircraft. The incident occurred to N387SW, a 15-year old airframe delivered to Southwest in June 1994.
The hole was discovered in the upper fuselage just ahead of the vertical fin. It is clearly visible in the ceiling towards the back of the cabin in images taken inside the aircraft.
The incident prompted the airline to immediately carry out inspections of its 180-strong 737-300 fleet which "did not find any issues". The US National Transportation Safety Board has launched an investigation into the incident.
Southwest's oversight regime ran into problems last year when the US Federal Aviation Administration stated that it had been operating nearly 50 737 aircraft without meeting requirements for repetitive inspection to detect fatigue cracks in the fuselage.