The landing gear on a small, private plane collapsed after it touched down at National Airport yesterday morning, delaying or diverting other flights until the crippled aircraft could be removed from the runway. None of the plane's four occupants was injured, airport officials said.

The small plane, a twin-engine Piper Aztec arriving from New York shortly after 11 a.m., ground to a halt at the intersection of the airport's two longest runways, leaving only the shortest of the runways open. Airport officials said normal operations resumed two hours later after a crane had towed the disabled plane off the runway intersection.

"The airport wasn't closed," said FAA spokesman David Hess. "But since the one operational runway was the shortest of the three, some pilots elected to divert to BWI or Dulles."

Some airliners used the third runway, Hess said, but other pilots decided to wait until the main runways were cleared before taking off. Eastern's shuttle service to New York was canceled until 1:41 p.m.

"There were some inconveniences, but it so happened that it occurred at a time when we didn't have a heavy schedule," Hess said.

The names of the pilot and the passengers were not available.