The National Transportation Safety Board said the Boeing 737 skidded 2,175 feet on its nose after the front gear collapsed backwards into the fuselage, damaging avionics and electronics. Nine people out of 150 passengers and crew on board suffered minor injuries, the NTSB said.
The agency had been considering not investigating the incident further, but decided on Tuesday it required further scrutiny. The accident occurred at 5:45 p.m. (2145 GMT) as Southwest's Flight 345 arrived at LaGuardia from Nashville, Tennessee.
The NTSB has an investigator at LaGuardia and is reviewing flight data and cockpit voice recorders at its Washington headquarters. It will also interview the pilots.
Boeing said it has people at the airport who are supporting Southwest and is providing technical assistance to the NTSB.
The landing gear is made by a unit of United Technologies Corp. Company officials have said they were looking into the incident, but could not be reached for further comment.
The runway where the jet landed reopened on Tuesday, though the airport reported delays through the day. There were delays of around 90 minutes on Tuesday morning as result of the incident, said Steve Coleman, a spokesman for the Port Authority of New York and New Jersey, which runs the area's airports. There were similar delays at the airport on Tuesday afternoon, but they were a result of low clouds, he said.
The hobbled plane was towed to a hangar, Coleman said.
Southwest spokeswoman Whitney Eichinger said the carrier was cooperating with the safety probe but could not predict how long it would take.
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