In cooperation with Boeing, Southwest Airlines has set up an additional inspection program for 79 of its Boeing 737-300s as the airline works to complete inspecting much of its 737-300 fleet for metal fatigue.
Southwest Airlines is inspecting the 79 737-300s following the Flight 812 incident at 33,000 feet over Arizona on April 1, when a 6-foot-long skin panel in the ceiling of a Southwest Boeing 737-300 registered N632SW ruptured, creating an opening to the outside air. The cabin of the aircraft depressurized and the pilots performed an emergency descent to 11,000 feet to create a breathable air pressure inside the cabin before making an emergency landing at Yuma in Arizona.
The aircraft was operating a Phoenix-Sacramento scheduled service. There were 118 passengers on board and five Phoenix-based crew members aboard Southwest Flight 812. Preliminary reports indicated the aircraft lost pressure and the passenger emergency oxygen masks deployed, according to Southwest.
After the Boeing 737-300 landed safely in Yuma, the crew confirmed a hole in the top of the aircraft, approximately mid-cabin. One flight attendant was treated at the scene for a minor injury, as was at least one passenger. No injuries required transport to the hospital, according to Southwest.
The carrier arranged for a Southwest Airlines aircraft to transport the passengers from Yuma to Sacramento in the evening of April 1.
The National Transportation Safety Board (NTSB) is investigating the incident. Southwest says it is continuing to cooperate with the ongoing investigation led by the NTS) into the cause of the hole in the aircraft which diverted to Yuma.
While the Boeing 737-700 is the mainstay of the Southwest Airlines fleet – the carrier operating and holding orders and other purchase rights for nearly 600, not including the additional 737-700s it would acquire upon its planned takeover of AirTran Airways – Southwest also operates 173 Boeing 737-300s and 25 737-500s
Southwest says the additional inspection agreed with Boeing involves a non-destructive test (NDT) involving passing a high-frequency eddy current throughout the fuselage skin of the 79 737-300s. This test is designed to detect any sub-surface fatigue in the skin that is not visible to the eye.
As of 4 p.m. Central time on Sunday, April 3, 19 aircraft had undergone the intense inspection with no cracks found, and Southwest returned those 737-300s returned to service.
However, in two other 737-300s, the testing did detect small, sub-surface cracks, according to Southwest, which says further evaluation and potential repairs will be necessary before those aircraft are returned to service.
Inspections of the 58 remaining aircraft in the sub-fleet will continue for the next few days. When inspections of aircraft are completed with no cracks found in those aircraft, Southwest says it will continue to them back into service by April 4. The airline anticipates completing the inspections by late on April 5.
The airline says the 79 aircraft designated for the additional inspections were designed differently in the manufacturing process to Southwest’s other 737-300s.
Southwest was expecting to cancel approximately 300 flights on April 3 while the inspections continued. The airline says customers should continue to check at www.southwest.com to see if there are any changes to their flights as a result of inspections and out-of-service aircraft.
“Boeing has since identified an inspection program for this section of the aircraft. Based on this incident and the additional findings, we expect further action from Boeing and the FAA for operators of the 737-300 fleet worldwide,” says Mike Van de Ven, Southwest’s executive vice president and chief operating officer.
Southwest operates an all-737 fleet of 548 aircraft. The airline says its fleet is constantly undergoing rigorous checks and inspections as directed by the FAA and Boeing, the aircraft manufacturer. These checks and inspections are dictated by the number of cycles an aircraft has accumulated (a cycle is a takeoff and landing) and on a calendar basis as well.
“Our highest priority is the safety of our employees and customers,” says Van de Ven. “Prior to the event regarding Flight 812, we were in compliance with the FAA-mandated and Boeing-recommended structural inspection requirements for that aircraft. What we saw with Flight 812 was a new and unknown issue.”
Adds Van de Ven: “We regret any customer inconveniences as a result of the inspections currently underway. Delays and cancelations are never the preference; however we are taking every precaution we can to ensure that our operation is safe.”
Related to this story:
- Southwest Places Firm Order for 150 Boeing 737 MAX and 58 737NG Jets
- FAA to Issue Emergency Directive Requiring Inspections of Older 737s
- Southwest to Fly 737-800s from Early 2012 Following Pilots’ Thumbs-Up
- Air New Zealand Orders A320s to Replace Domestic Boeing 737-300s
- FAA Gives Southwest 4 Months to Replace Unapproved Parts
