At 18:35 Pacific time, a Cessna 340A overran runway 21, vaulted an embankment and came to rest on an airport service road during an aborted takeoff at Santa Monica Municipal Airport. The pilot and passenger were killed. Witnesses reported the airplane passing low and fast down the runway. They then reported hearing the engines retarded to idle, skidding noises and the sound of impact. A flight instructor saw the airplane taxi directly from an airport restaurant parking area to the runway, without stopping in the runup area. The airplanes flight control lock was found installed in the pilots control column.