What happened
On May 27, 2017, an ASK 21 Mi glider, registration LN-GMI, was performing a training flight at Elverum Airport Starmoen (ENSM) as part of an introductory course. The flight, operated by Gardermoen Seilflyklubb, involved an instructor and a student.
During the final approach, the instructor decided to execute a short landing to ensure the aircraft was available for the next scheduled user. As the aircraft passed a tree line at approximately 15 meters altitude and 100 km/h, the instructor deployed full air brakes to facilitate the steep descent. This maneuver triggered an immediate and overwhelming panic response from the student.
The student pulled the control stick to the maximum rear position, causing the instructor to lose grip on the controls. The aircraft's pitch shifted from nose-down to neutral. The student then pushed the stick to the maximum forward position, causing the aircraft to pitch down sharply. The glider struck the grass runway nose-first at an estimated speed of 130-140 km/h. The impact caused the aircraft to bounce into the air and strike the ground again before the instructor could regain control and bring the aircraft to a stop.
The investigation
The Norwegian Safety Investigation Authority (NSIA) examined the flight sequence, the physical state of the aircraft, and the mental and physical condition of the occupants. The investigation noted that the student was experiencing physical and mental fatigue due to a long day of outdoor activity and previous flight maneuvers.
Investigators also looked into the communication between the crew. While the instructor had previously taken control of the aircraft and issued a command that he was flying, the student could not recall receiving this instruction. The lack of a voice recorder prevented a definitive determination of the communication exchange.
Findings
- The primary cause of the accident was a sudative panic reaction by the student pilot during the landing phase.
- The student's extreme physical movements on the control stick directly led to the loss of aircraft attitude control.
- The instructor's decision to perform a short landing was made with very little time to brief the student on the different flight characteristics of such a maneuver.
- The student was likely experiencing mental and physical exhaustion, which may have lowered his threshold for a fear response.
- The instructor's handling of the student's erratic movements likely prevented physical injuries to both occupants.
No physical injuries were sustained by the crew, but the ASK 21 Mi sustained significant damage, including a deformed nose section and a cockpit section that required replacement.