The problems with JetBlue Flight 292 marked at least the seventh time that the front landing gear of an Airbus jet has locked at a 90-degree angle, forcing pilots to land commercial airliners under emergency conditions, according to federal records.

No one has been injured in the incidents, which span roughly a decade. There are more than 2,500 planes in operation worldwide from the Airbus 320 family, which includes the related Airbus 318, 319, and 321 models. Aviation safety officials yesterday noted that the planes have a good safety record.

In the most recent case, JetBlue’s flight from Burbank to New York’s John F. Kennedy International Airport, carrying 140 passengers, was forced on Wednesday to make an emergency landing at Los Angeles International Airport. The plight of the aircraft was televised nationwide, beginning with the plane circling over the California coast and ending at an LAX runway with a landing marked by fire streaming from the plane’s front wheels.

A senior air safety investigator with the National Transportation Safety Board, which is investigating Wednesday’s incident, Howard Plagens, called problems with landing gear “common.” At a news conference yesterday at the Proud Bird Restaurant outside LAX,he said he believed passengers had no reason for concern about the safety of the Airbus fleet.

“How many Airbus A320s are out there?” he said, noting that the number of times the wheels have locked is small.

“Incidents happen every day” involving landing gear of all types of planes, he said.

The locking of the nose gear on Airbus jets is one of several recurring problems with the plane’s nose landing gear. A Canadian study issued last year documented 67 incidents of nosewheel failures on Airbus 319, 320, and 321 aircraft worldwide since 1989.

Mr. Plagens said that the A320 wasn’t grounded following previous incidents involving the nose gear because “they did do fixes for those things.”

After the initial investigation, the NTSB will look at maintenance records for other Airbus A320 aircraft, Mr. Plagens said. Investigators will review other instances involving the popular plane’s nose wheel, as well as modifications recommended to fix the problem.

“If we find a pattern, we’ll certainly do something,” he said.

NTSB officials expect the investigation into Flight 292’s emergency landing to take six to nine months. They already have removed the cockpit voice recorder and the digital flight data recorder from the plane and sent them to Washington for evaluation. In the next few days, safety officials will decide whether to send the entire landing gear assembly to New York, where mechanics would take it apart piece by piece and reassemble it to try to recreate the failure.