Southbridge

During landing the aircraft impacted hard and skidded down the runway before it went off the left side of the runway. The left main wheel separated and the nose gear collapsed. Both pilots stated the landing approach was normal until the aircraft was approximately 15 feet above the runway at which time the aircraft abruptly descended and impacted hard with the runway. Prior to the impact, the aircraft was configured with 20° of flaps and landing gear was down and locked. The airspeed was 105 knots. Examination of the aircraft disclosed that the aft main gear doors were open and the nose down lock limit switch was defective. The switch is required to close the aft main gear door. The flight test by the mfg determined that opened aft main gear door has none to unnoticeable effect on stall speed. Aircraft speed at touchdown based on computations from prop slash marks was 86 knots. The stall speed of aircraft at prevailing weight and flaps configuration is below this speed, the aircraft weight was approximately 9,000 lbs.