 Allen Stubblefield was on the flight. We're within probably two minutes of landing and that's when the pilot came on and said everybody to their emergency positions and all of the flight attendants immediately went into brace, brace, brace, brace, brace, brace. Each set of landing gear is equipped with multiple wheels and Flight 1001 touched down safely in Denver. But Monday's incident marks the second time a wheel has fallen off a United plane during takeoff in the last four months.