A Southwest Airlines plane rests on the tarmac  after what officials say was a nose gear collapse during a landing at LaGuardia Airport, Monday, July 22,
A Southwest Airlines plane rests on the tarmac after what officials say was a nose gear collapse during a landing at LaGuardia Airport, Monday, July 22, 2013, in New York. (John Minchillo / AP)

A Southwest Airlines jet bellied onto a runway at New York's LaGuardia airport when its nose gear collapsed on landing.

The runway remained closed Tuesday after the accident Monday evening, causing delays of up to two hours and adding to disruptions from thunderstorms in the nation's busiest air-travel market. Flight 345, a Boeing Co. 737-700, came to rest with its front end flat on the ground, and emergency evacuation slides deployed.

While Southwest reported eight injuries among the 150 people aboard and dramatic photos and videos flooded social- media websites, the incident ended without serious harm beyond the damage done to the jet. The episode was a "very rare occurrence" for the industry and Southwest, John Nance, a former 737 pilot, said in a telephone interview.

"They've got superlative maintenance," said Nance, who runs consulting firm John Nance & Associates in University Place, Washington. "The reality is there is so little that goes wrong with the system, unless we started having one of these on a regular basis, this really isn't something anybody should be worrying about."

Some arriving flights averaged delays of two hours, 13 minutes as of 7:15 a.m. New York time, according to the U.S. Federal Aviation Administration's website, which listed "disabled aircraft" as a cause.

Counting arrivals and departures, New York's three major airports had more than 200 cancellations, of 274 reported in the U.S., according to industry data tracker FlightAware.com. LaGuardia's tally alone topped 100 flights, and the FAA told pilots that Runway 4-22 was shut.

Flight 345 was arriving from Nashville, Tennessee, at about 5:45 p.m. yesterday when the gear failed. A U.S. National Transportation Safety Board investigator was looking into the case, as was the FAA, according to agency statements.

"Eyewitness reports indicate the aircraft's nose gear collapsed upon landing," Dallas-based Southwest said in a statement. The FAA initially said the crew reported landing-gear issues while nearing the airport. Then the agency withdrew that assertion and said the case remained under investigation.

Planes with a so-called tricycle gear like the 737 touch down first with their rear main wheels, then lower the nose as they decelerate and complete their rollout. The FAA said Flight 345 landed on Runway 4, which according to industry website AirNav.com is 7,001 feet (2,134 meters) long.

Of the eight people initially reported hurt, five were passengers and three were flight attendants, said Michelle Agnew, a Southwest spokeswoman. "We're just working closely with local authorities and the NTSB at this time," she said.

Southwest is the largest operator of the Boeing 737, a single-aisle, twin-engine plane that is the world's most widely flown jetliner. The accident was the third this month, with varying degrees of severity, involving a Boeing jet.

On July 6, a Boeing 777 flown by Asiana Airlines Inc. crashed on landing in San Francisco, leaving three people dead and scores injured. On July 12, an empty 787 Dreamliner operated by Ethiopian Airlines Enterprise caught fire on the ground at London's Heathrow airport.

Delta Air Lines Inc., the biggest carrier at LaGuardia, issued a waiver to allow passengers to rebook flights without penalty, while No. 2 American Airlines said it was bracing for the possibility of "dozens" of trips being removed from its schedule.

--With assistance from Alan Levin in Washington and Mary Jane Credeur in Atlanta. Editors: Ed Dufner, Cecile Daurat