NTSB testing jetliner with hole

WASHINGTON – 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 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.