What happened
On February 13, 2015, a private flight involving a PA46-500TP (Malibu Meridian), registration N164ST, was conducting a flight near Stockholm Västerås Airport. During the flight, the aircraft experienced an engine failure. As the pilot attempted to manage the emergency, the aircraft entered a left turn and subsequently struck the ground on Björnö island. The impact was characterized by a significant side-on angle, which caused the wings to separate from the fuselage. Despite the destruction of the aircraft, the occupants sustained only minor injuries.
The investigation
The Swedish Accident Investigation Authority (SHK) conducted an extensive examination of the wreckage and the flight sequence. Investigators analyzed the engine and propeller systems, including technical examinations by Pratt & Whitney Canada and Hartzell Propeller Inc. The investigation also reviewed the aircraft's flight data acquisition unit and the condition of the fuel.
Structural analysis of the wreckage, supported by experts from XICE AB, revealed that the aircraft's impact angle was a critical factor in the survival of the occupants. The investigation determined that the aircraft struck the ground with its left wing first while in a left bank. The force of the impact caused the left wing to break at the root, followed by the right wing breaking into two pieces as the fuselage continued to rotate. The investigation also noted that the soft, moisture-saturated ground helped absorb much of the impact energy.
Findings
- The primary cause of the accident was an engine failure during the flight.
- The aircraft struck the ground at a steep angle, likely at least 45 degrees, which prevented the engine from being pushed directly into the cockpit.
- The separation of the wings acted as a significant energy reduction mechanism, absorbing much of the kinetic energy during the crash.
- The relatively low speed at the time of impact and the soft nature of the terrain mitigated the peak G-forces experienced by the cabin.
- The robust construction of the pressurized cabin helped maintain its structural integrity during the sequence of impacts.