Southwest Airlines Flight 812

Southwest Airlines Flight 812 was a domestic flight from Phoenix Sky Harbor International Airport in Phoenix, Arizona to Sacramento International Airport in Sacramento, California operated by a Boeing 737-300 passenger jet. On April 1, 2011, the flight suffered rapid depressurization while cruising at 34000 ft near Yuma, Arizona, leading to an emergency landing at Yuma International Airport. Two of the 122 people on board suffered minor injuries.

The depressurization was caused by the structural failure of the fuselage skin, which produced a hole approximately 60 in long on the upper fuselage. The NTSB investigation revealed evidence of pre-existing metal fatigue, and determined the probable cause of the incident to be related to an error in the manufacturing process for joining fuselage crown skin panels.

The incident was the second of this type in less than two years, following the structural failure of Southwest Airlines Flight 2294 in 2009, and led to the FAA increasing the inspection rate of certain airframes.

Incident

Flight 812 was a domestic scheduled passenger flight from Phoenix Sky Harbor International Airport, to Sacramento International Airport. On April 1, 2011, it was carrying five crew and 117 passengers. Takeoff and initial climb-out were normal. As the aircraft approached its cruising altitude, at approximately 15:58 local time (22:57 UTC), while climbing through FL344 (34400 ft) to reach FL360 (36000 ft), a loud bang was heard, recorded as an unidentified noise on the cockpit voice recorder (CVR). According to eyewitnesses, one of the ceiling panels dislodged.

About two seconds later, the captain announced that cabin pressurization had been lost, and called for oxygen masks on. At this point, sounds of increased wind noise were heard on the CVR. Cabin oxygen masks deployed. The captain declared an emergency to air traffic control, and received clearance to make an emergency descent. The pilots performed a rapid descent to 11000 ft, where atmospheric pressure is sufficient to prevent hypoxia. At this point the flight attendants began relaying reports to the pilots of an injury and a "two-foot hole" in the fuselage. The pilots requested a further descent to 9,000 ft and vectors to the nearest airport that could accommodate the 737. The aircraft then landed without further incident at 16:23 at the joint Marine Corps Air Station Yuma/Yuma International Airport.

One flight attendant and an off-duty airline employee received minor injuries, but were both treated at the airport. The flight attendant had been attempting to make an interphone call to the pilots or a PA announcement to the passengers, instead of immediately donning his oxygen mask as he had been trained. As a result, he lost consciousness, fell, and struck the forward cabin partition, breaking his nose. An off-duty airline employee rushing to assist the flight attendant also lost consciousness, fell, and received a cut to the head. Both regained consciousness as the aircraft descended. A spare aircraft with maintenance technicians, ground crew, and customer service agents was dispatched from Phoenix to take the passengers to Sacramento. The replacement aircraft was expected to reach Sacramento with a 4-hour delay to the passengers on board Flight 812.

This was the second structural failure, rapid decompression, and emergency landing for Southwest Airlines in two years. Southwest Airlines Flight 2294, also a 737-300, suffered a football-sized hole in its fuselage on July 13, 2009, in a similar incident. That aircraft also made a safe emergency landing.