Incident Description
On 13 July 2020, training flights involving glider towing were conducted at Nowy Targ airport (EPNT). The exercise was the final stage of a student pilot's training in glider landing in unprepared terrain. After an instructional flight, the student was cleared for solo flights. The first solo flight was executed correctly. At 14:50 local time, the student commenced the second solo flight. During the initial climb, the towplane and glider followed a right-hand two-turn pattern. At an altitude of 250 meters, the tow pilot initiated a 180-degree second turn to align for glider release. During this maneuver, the student failed to maintain proper coordination, causing the glider to move inside the turn and below the towplane. In the final phase of the turn, the tow pilot experienced a significant loss of controllability and a decrease in airspeed. He commanded the student to release the towline. Both pilots subsequently released the towline, but due to the speed loss, the towplane entered a left spin. The tow pilot recovered from the spin after three-quarters of a turn at 150 meters and landed at the airport. The supervising instructor radioed the student to perform a standard traffic pattern, and the glider landed safely.
Findings
The Polish State Commission on Aircraft Accident Investigation determined the cause of the incident: incorrect positioning of the glider during the towed flight in a turn, which resulted in a disturbed flight path and a spin of the towing aircraft.
Contributing Factors
Two contributing factors were identified: the student pilot's limited experience, and the relatively low empty weight of the towing aircraft compared to the heavy glider, which made control more difficult when the glider was improperly positioned.
Recommendations
The operator of the aircraft proposed preventive measures, including additional theoretical instruction for the student on unusual situations in towed flights, continuation of training after 10 proficiency flights with an instructor, and ongoing awareness for tow and towed pilots regarding precise piloting requirements when the tow plane's weight is comparable to or less than the glider's weight. No additional safety recommendations were issued by the commission.