What happened
During the final stages of the landing sequence, the aircraft underwent an abrupt descent while approximately 15 feet above the runway surface. The aircraft struck the runway with significant force and subsequently skidded along the pavement before exiting the left side of the runway. This impact caused the nose gear to collapse and led to the separation of the left main landing gear.
At the time of the incident, the aircraft was flying at an airspeed of 105 knots with the landing gear in the down and locked position and flaps set to 20 degrees. Based on propeller slash marks, the touchdown speed was calculated to be 86 knots. The total weight of the aircraft during this operation was roughly 9,000 lbs.
Findings
An inspection of the wreckage revealed that the aft main gear doors were in an open position. Investigators identified a defective nose down lock limit switch, which is the component responsible for ensuring the aft main gear doors close properly. While manufacturer flight testing indicated that an open aft main gear door has negligible impact on stall speed, the aircraft's weight and configuration meant the touchdown speed remained above the stall threshold.
Official findings regarding the sequence of events included several contributing factors:
- An excessive descent rate during the landing phase
- The inability to maintain a level off during the flare/touchdown phase
- Structural overload of both the nose gear and the main landing gear