The National Transportation Safety Board (NTSB) is investigating Monday’s nose-down landing of a Southwest Airlines Boeing 737-700 at LaGuardia Airport in New York.

After the front gear collapsed backwards and upwards into the fuselage, the plane skidded 2,175 feet on its nose, causing injuries to nine out of the 150 passengers and crew members on board – who evacuated the aircraft via its slides, which deployed normally.

The gear collapse damaged the electronics bay, which houses avionics and other equipment as well as the exterior of the airplane.

The accident closed LaGuardia for more than an hour Monday evening and caused the cancellation of 180 flights. Although the affected runway was reopened on Tuesday, residual delays continued on Tuesday.

The the flight data recorder and cockpit voice recorder have already been sent to the NTSB laboratory in Washington for downloading and analysis.

The NTSB says its investigation will include interview with the pilots interview the pilots and witnesses and reviews of any video or photo evidence of the accident, relevant records and possibly tests of materials in its laboratory.

A spokesperson for Southwest Airlines said the company is cooperating with the NTSB in its investigation.

The landing gear is made by a unit of United Technologies Corp.