Accident Details
On 19 July 1969 at 1725 hours, a student pilot departed on his 97th flight in the Rhönlerche II glider, registration HB-576. The flight was a solo aerotow. After performing three right-hand spirals, the pilot circled left over the usual point. He turned onto the left base leg for runway 26 at an altitude of 180 m above ground, briefly extended the air brakes, and then entered a left sideslip on final approach at 80 km/h while extending the air brakes again.
According to the pilot, during the sideslip he focused on maintaining direction and preparing for the landing. Despite using opposite rudder, he could not correct a deviation from the intended path. After stopping the sideslip, he left the air brakes extended and realized he was heading directly toward trees standing short of the runway. He considered a lateral avoidance maneuver risky due to possible wingtip contact with the ground and hoped to clear the trees. The airspeed remained 80–85 km/h. The pilot believes he may have retracted the air brakes upon sighting the trees, but is not certain; the instructor observing from the ground stated the brakes remained extended until impact.
The glider collided with the tops of two trees on the right side (as seen from final approach), rotated 180° to the left, and struck the ground. The accident occurred at 1734 hours.
Injuries and Damage
The student pilot was uninjured. The glider sustained substantial damage, including a section of the left wing being torn off. Damage to the trees was relatively minor.
Pilot and Training
The student pilot, born in 1941, held a valid student pilot certificate for powered and glider aircraft, issued on 17 July 1962 and last renewed until 13 February 1971. He began training on 31 July 1962 at Birrfeld, with interruptions: training was suspended in summer 1962, resumed in spring 1965 with few flights, and only in summer 1966 did he perform his first solo glider flight. After recognizing a lack of knowledge of air traffic regulations, he completed a theory course in winter 1968/69 and resumed practical training in spring 1969.
His total flight experience was 97 flights totaling 13 hours 41 minutes, comprising 30 winch launches (1h34m), 32 aerotow dual (5h14m), and 35 aerotow solo (6h53m). In the three months prior to the accident, he had 4 dual aerotows (0h49m) and 15 solo aerotows (4h09m). All training was conducted on the Rhönlerche II. Four different instructors had supervised his training; he was solo on the accident flight.
Aircraft and Environment
The glider was a Rhönlerche II, designed by Schleicher/Kaiser and built in 1956 by A. Schleicher, Poppenhausen, West Germany. It was owned and operated by Fliegerschule Birrfeld. Weight and center of gravity were within limits at the time of the accident.
The accident site was Birrfeld airfield, elevation 400 m, with a 600 m by 30 m grass runway 08/26. Runway 26 was in use. The southern part of the airfield was reserved for glider operations. Approximately 200 m before the threshold of runway 26 (southern section) stood three trees 4 to 6 m high.
Weather was sunny and cloudless with light wind from the northwest. At the accident time, the sun had an elevation of 25° and an azimuth of 274°, causing significant glare, especially considering the often-scratched plexiglass canopies of training aircraft.
Findings
The accident occurred within the training operations of Fliegerschule Birrfeld. The pilot was properly licensed and, by the accident flight, sufficiently trained, although his training had been spread over seven years.
The final approach was flown too low, resulting in collision with trees. The pilot did not take evasive action after realizing the danger, instead hoping to clear the trees. Retracting the air brakes and increasing speed might have allowed clearing the obstacle.