What happened
On June 22, 2013, a Progressive Aerodyne Inc. Searay amphibious aircraft, registration LN-HGN, was performing landing approaches at Gol Airport (ENKL) in Norway. The aircraft had been out of service during the winter due to engine issues, and the pilot had been conducting flight training to refresh certifications in the days leading up to the event.
During the first landing attempt on runway 29, the aircraft touched down with the left wing low. Immediately upon contact with the runway, the aircraft began a sharp leftward veer. Despite the pilot applying full right rudder, the aircraft could not be corrected and exited the paved portion of the runway. Approximately 45 meters after leaving the asphalt, the aircraft struck an 8-meter wide, 1-meter deep ditch. The impact with the ditch edge caused the aircraft to pivot right while simultaneously rotating left on its vertical axis, leading to significant damage to the fuselage, tail section, and landing gear.
The investigation
Investigators examined the wreckage and the ground tracks left by the aircraft. While the pilot initially suspected a mechanical failure in the tailwheel mechanism due to the aircraft's sudden deviation, the investigation revealed that a mounting bolt had sheared due to the impact with the ditch, not due to a pre-existing malfunction. The rudder and tailwheel steering were found to be functioning normally prior to the accident.
Analysis of the tracks showed that the aircraft left the paved surface at a sharp angle, approximately 15 meters after touchdown. The investigation also noted that the aircraft's brakes were slightly applied, which may have contributed to the asymmetric drag. Furthermore, the physical characteristics of the ditch, which contained stones and sharp edges, were found to have exacerbated the structural damage to the aircraft's hull.
Findings
- The primary cause of the excursion was the failure to maintain the aircraft's alignment with the runway centerline during the landing roll.
- A contributing factor was the pilot's failure to lower the right wing into the wind, which likely exacerbated the leftward rotation.
- The pilot's limited recent experience with this specific aircraft type and the lack of recent flight time may have contributed to the loss of control.
- The lack of differential braking capability on this aircraft model made it more difficult to arrest the developing ground loop.
- The presence of stones and the sharp edge of the drainage ditch increased the severity of the damage to the LN-HGN.