Boeing 737 landing gear failure

The Boeing 737 from Piedmont airlines, with 106 people aboard, was flying from Washington to Charlotte, N.C., when the crew could not get the main left landing gear down. It was diverted to Greensboro for an emergency landing. The crew brought the aircraft onto the runway as slow as possible, and managed to land. No one was injured.
Investigators have found that rubber wheel blocks were left in the gear well, jamming the left gear in up position.