2019 Ohlstadt-Pömetsried glider accident

Overview and immediate events On 19 October 2019, a two-seat Alexander Schleicher ASK 13 glider was destroyed when it struck a tree and fell into a wooded area near the Ohlstadt-Pömetsried glider field. The aircraft was on a training flight with a flight instructor and a student. The instructor sustained serious injuries, and the student sustained minor injuries. The accident also caused damage to the ground. ## Flight details The glider made a winch launch at 14:01 local time from the Ohlstadt-Pömetsried glider field, with a launch heading of 040°. The release height was 340 metres above the launch site. GPS data from a collision-warning device showed that after release the aircraft flew roughly 1,000 metres straight ahead before turning into the crosswind leg and then the final approach. According to the student, roll manoeuvres were carried out in the final-approach area, as had been done on the two previous launches. Shortly before reaching the crosswind leg, the instructor said he wanted to conduct a simulated cable-break exercise. He increased speed to as much as 170 km/h, in the yellow arc, and the flaps were extended by the time the aircraft reached the middle of the field after the crosswind turn. In the last quarter of the field length, the instructor asked whether the student wanted to take the controls; she declined, and he continued flying. The student said the altitude was low at that point and she was concerned about a red radio mast. She then noticed a tree contact on the cockpit canopy, after which the glider crashed into the forest. Witnesses to the manoeuvre said they did not observe the flaps being extended. Flight data showed that ground speed averaged 90 km/h from release until the crosswind leg, then rose to 140 km/h. At the last quarter of the field length, ground speed was 98 km/h at an altitude of 30 metres above the airfield level, or about 20 metres above a tree- and shrub-covered slope at the south-eastern edge of the field. Witnesses at the north-eastern end of the field reported that the ASK 13 turned about 30° to the right shortly before reaching the north-eastern boundary and was flying relatively slowly. The glider did not gain enough altitude to clear the tree line at the boundary and its left wingtip caught in a tree crown. It then spiralled left into the forest and became entangled in the trees. ## People The 60-year-old flight instructor held an unlimited glider licence, converted in 2014 to an EU sport pilot licence (SPL). His licence included winch, aerotow, self-launch and aerobatic ratings, a touring motor glider (TMG) rating, and an instructor rating for gliders, touring motor gliders and aerobatics valid until 30 September 2020. His Class 2 medical certificate was valid until 30 March 2020 and carried a restriction for distance vision correction. In 2018, the instructor had made 91 launches and about 65 flight hours, mainly as a glider instructor and as pilot-in-command of TMGs. In the 90 days before the accident, he had made 20 launches and 6 flight hours, including 8 launches and 45 minutes in the ASK 13. On the day of the accident, he had made five winch launches in the ASK 13 with three different students. The 14-year-old student had begun her glider training on 14 September 2019. By the time of the accident flight, she had completed 16 training flights totalling 2 hours 26 minutes over five days with six different instructors. She had flown with the accident instructor for the first time on the day of the accident and had completed two circuit flights with him before the accident flight. ## Aircraft The ASK 13 was a two-seat mixed-construction glider with tandem seating, built in 1971 by Alexander Schleicher in Poppenhausen/Rhön with serial number 13 290. It was a cantilevered mid-wing glider designed for basic training, with a fabric-covered steel-tube fuselage and a 16-metre wingspan. The aircraft was registered in Germany for traffic and was privately owned. Its last airworthiness inspection was on 10 January 2019. Total operating time was 3,823 hours and 11,766 launches. A weighing report dated 17 December 2018 gave an empty mass of 316.3 kg. The minimum load for the front seat was 65 kg according to the flight manual. The student weighed 50 kg; her rescue parachute and the trim weight on the front seat together weighed 18 kg. ## Meteorological and airfield information A flight instructor who had been operating on 19 October 2019 reported normal visual-flight conditions with light turbulence after a rain area had passed. The wind was from north-west directions and was light at the time of the accident, with a “hanging windsock.” Routine weather reports (METARs) at Munich Airport (EDDM) on 22 September 2019 showed visual-flight conditions (CAVOK), visibility over 10 km, and a temperature of 15°C. The Ohlstadt-Pömetsried glider field is about 50 km south-west of Munich and 4 km south-east of Murnau am Staffelsee, at an elevation of 661 m AMSL. It has a winch-tow strip about 1,000 m long and an asphalt runway 880 m by 10 m, oriented 040/220°. ## Accident site and aircraft findings The accident site was about 100 m north-east of the boundary of the Ohlstadt-Pömetsried glider field. The glider was hanging in the upper half of a steep, deciduous high forest with trees about 25 m tall, wedged between smooth tree trunks. The longitudinal axis was roughly north, with the nose at a 45° angle to the ground. The right wing was pointing upward and the left wing downward. The one-piece Plexiglas canopy was shattered, and the canopy frame was on the fuselage. The forward fuselage segment was visually undamaged apart from scratches and abrasions. The rear fuselage was bent about 1 m behind the wings. The rear fuselage with the rudder was complete and showed some abrasions. Only the fin remained on the tail boom; the elevator was found on the ground. The wings showed breaks and notches over their full length in the covering area up to the spar. The fabric between the spar and the trailing edge was torn in places. Each wing was cut once from the leading edge to behind the spar. On the left wing, the cut was about 1.5 m from the root; on the right wing, it was about 4.5 m. The left wing’s drag flaps were extended about 10 cm on the upper and lower surfaces. ## Additional information The seriously injured flight instructor could not be interviewed because of memory loss. According to the training manager of the gliding club at Ohlstadt-Pömetsried, cable-break exercises focus on straight-in landings at low altitude and on the turn-back when altitude is insufficient for a shortened circuit, due to the particular site conditions. The first cable-break exercise is normally carried out no earlier than after 25 to 35 glider launches, depending on the student’s progress. The German Aero Club (DAeC) glider training methodology, January 2017 edition, recommends under point 1.8.1 on start-interruption behaviour that the actions to be taken after start interruptions must become subconscious so that they are performed correctly. Only those who have trained and mentally rehearsed such situations can act appropriately in an emergency. It states that at least three start interruptions at different altitudes must be conducted with the student during training for the first solo flight, and that start interruptions at greater altitude should also be simulated in free flight. Start interruptions are to be practised in all training phases. The student’s training level must be advanced enough for the instructor to expect independent and sensible action. Before the exercises, thorough instruction is required on the launch process, possible start interruptions at different altitudes and flight attitudes, and the sequence of actions. Procedures, depending on local conditions, aircraft type, altitude, wind direction and strength, are to be mentally and verbally rehearsed and checked. If a straight-in landing is not possible and a shortened circuit or turn-back is flown, the aircraft should, where terrain permits, fly away from the field with the wind so that the last turn can be flown into the wind. These exercises must be agreed in advance with the winch operator and must be conducted so that they resemble a real start interruption. The instructor or winch operator interrupts the launch by releasing (or by reducing tow power) at a height of their choosing.