What happened
On April 1, a captain for a commuter air carrier was tasked with repositioning an aircraft from Sacramento to Santa Barbara. The pilot had requested to be located in either the Los Angeles or Santa Barbara area by this date. Because the pilot had never flown this specific aircraft solo and did not wish to wait for a co-pilot, he proceeded with the flight alone.
The pilot reported that after climbing to 17,500 feet and trimming the aircraft for cruise flight, he dozed off several times during the flight. Upon his final period of awakening, the pilot discovered the aircraft was in a descent at speeds exceeding 300 knots, which is well above the aircraft's maximum velocity never exceed (VNE) of 246 knots. The pilot was only able to recover the aircraft from this high-speed descent by utilizing the electric trim.
The investigation
Damage to the upper wing skin panel was discovered by a passenger during a subsequent flight. An investigation into the structural integrity of the aircraft revealed damage to the wing skin panels, stringers, and main spars. According to the aircraft manufacturer, for the observed damage to occur, the aircraft would have had to endure a calculated load factor of 7.8 G's.
The pilot noted that he had only received between 1.5 and 2 hours of sleep during the 24-hour period preceding the flight.