A United Airlines flight had just taken off from Los Angeles International Airport Monday morning when the pilot of another airplane noticed a problem: One of the main landing gear wheels had fallen off the Boeing 757-200 during takeoff. A third pilot saw the tire roll across two runways and end up in a cargo area, KTLA reports. The incident was reported to air traffic control, which diverted an Air Canada flight that was taxiing so that a crew could inspect the runway. Meanwhile, air traffic control also got in touch with United Flight 1001—the pilot appeared to have no idea the wheel had come off, and the plane continued on its way, landing in Denver as planned without incident, ABC News reports.
"The wheel has been recovered in Los Angeles, and we are investigating what caused this event," a United spokesperson says. As Bloomberg points out, this is not the first time this has happened. The last time, it was a United Airlines Boeing B777-200 that lost a wheel during takeoff from San Francisco, but in that case an emergency landing was required. That was one of several incidents that prompted a federal safety review of United Airlines, USA Today reports. The airline is still under "increased oversight," and the FAA will investigate Monday's incident. (More Boeing stories.)