By Sholnn Freeman
Washington Post Staff Writer
Wednesday, July 15, 2009
The National Transportation Safety Board is planning lab tests on a section of a Southwest Airlines 737-300 jetliner that lost a chunk of its metal skin on a Monday flight.
The plane was headed for Baltimore-Washington International Marshall Airport from Nashville when the rupture occurred. The aircraft lost pressure and made an emergency landing in Charleston, W.Va. No injuries were reported.
Peter Knudson, an NTSB spokesman, said the hole was 17 inches by 14 inches. He said the agency plans to cut a two-inch margin around the hole and transport the section to its Washington laboratory. Metal experts at the agency will examine it today, he said.
Investigators will also look at the plane's maintenance history, its manufacturing records and any indication of metal fatigue, manufacturing defect or previous damage. The agency also plans to retrieve the plane's flight data and cockpit voice recorders.
Meanwhile, an inspection check of Southwest's fleet of 737-300 aircraft did not find any airplanes with similar fuselage problems, said Whitney Eichinger, an airline spokeswoman. Southwest operates 181 such planes.
Officials do not yet know the cause of the rupture, which appeared on the top of the airplane, near the tail, said Marilee McInnis, another Southwest spokeswoman. Investigators will examine all possibilities, she said, including a sudden tear in the material or a separation of two attached panels.
Flight 2294, which was carrying 126 passengers and a crew of five, landed in Charleston 50 minutes after its 4:05 p.m. departure from Nashville. It had been scheduled to arrive in Baltimore about 8 p.m.
The loss of cabin pressure was detected about 30 minutes into the flight. Oxygen masks deployed, and the plane descended to a safe altitude, McInnis said. Oxygen is usually needed above 10,000 feet.
Another airplane was sent to Charleston to pick up the passengers, and they arrived at BWI shortly before 11 p.m., McInnis said.
Bill Voss, president of the nonprofit Flight Safety Foundation, said the situation could involve ground damage or undetected fatigue cracks in the fuselage, a known problem for aging aircraft.
A spokesman from the Federal Aviation Administration said the Southwest jetliner was delivered in 1994. As a 300 series plane, it is one technological generation behind Boeing's latest 737s, the 600 through 900 series. Because of past problems with cracks, the planes are supposed to be inspected rigorously.
Southwest is already under FAA scrutiny because of its failure to conduct mandatory checks on airplanes for fuselage cracks, and congressional investigators say they have uncovered lapses in FAA oversight of aircraft inspections at Southwest.
Last year, the government fined Southwest $10.2 million for flying thousands of trips using 46 Boeing 737s that had not been checked for fuselage cracks. Southwest fought the fine. In March, the FAA agreed to reduce the fine to $7.5 million on the condition that Southwest implement new safety measures.
The inspector general at the Department of Transportation, which oversees the FAA, has been critical of the FAA over its supervision of Southwest. The FAA relies heavily on self-reported data from airlines to spot trends that could lead to mechanical failures or plane crashes. The inspector general has complained that this approach has sometimes led to coziness between the airline and inspectors.
Steve Hall, 42, a passenger on Flight 2294, was seated in Row 21 when the hole opened. He said most passengers sat calmly during the 30-minute ordeal.
"You're sitting there chitchatting, and the next thing you know there's a loud pop and a sensation of your ear being under extreme pressure," Hall recalled yesterday from his home in Murfreesboro, Tenn., where he returned after missing his connection for a meeting in Pittsburgh. "You think to yourself, 'Oh, crap. I wish I would have paid attention to the safety procedures.' "
Staff writers Yamiche Alcindor, Martin Weil and Debbi Wilgoren contributed to this report.