Accident Overview
On Monday, 3 July 1972, at 09:36 hours Central European Time, a student pilot took off in a Rhönlerche II glider (registration HB-592) from runway 21 at Montricher airfield, towed by another aircraft. The flight was a training session for a glider pilot license, and the student was accompanied by a glider instructor. The tow release occurred at an altitude of approximately 300 meters above ground.
After release, the student executed two right-hand spirals northwest of the airfield. The previous day, the student had performed several flights with approaches and landings on runway 03. Despite the active runway being 21 (wind moderate to strong from the southwest), the student maneuvered for an approach to runway 03. The instructor did not intervene until he saw the student persist in the intention to land on runway 03; he briefly took control and directed the glider toward the circuit for runway 21.
By the time the glider was abeam the runway threshold, its altitude was only about 120 meters above ground. The HB-592 lost altitude rapidly during the late downwind leg and base turn of a somewhat shortened circuit. The instructor retook control on final approach and, after overflying the BAM Apples–L'Isle railway line, put the glider into a dive intending to clear a hedge 4 to 5 meters high located across the approach path about 175 meters from the threshold of runway 21.
The glider failed to clear the obstacle: its left wing struck a branch, and it was slowed by bushes before coming to rest at 09:46 hours at the edge of the hedge on the runway side.
Damage and Injuries
The occupants were unharmed. The glider sustained minor damage. There was no ground damage.
Pilot Information
The student pilot, born in 1926, held a valid student pilot certificate. Total flight experience was 23 hours, of which 13 hours 15 minutes were on the accident type. In the previous three months, he had flown 4 hours 45 minutes total, with 1 hour 15 minutes on type. Training had begun in July 1965, with 12 hours on type through 1966; training resumed at Montricher in 1971. Nothing suggested the student was in poor health at the time of the accident. Federal Air Office records showed no prior accidents or incidents.
The glider instructor, born in 1941, held a valid glider pilot license with endorsements for restricted radiotelephony, aerobatics, instrument flight, passenger authorization, a glider instructor license, and a private pilot license. Total glider experience was 390 hours 23 minutes with 1,150 landings, including 150 hours with 750 landings on the accident type. In the previous three months, he had flown 26 hours 29 minutes total, with 6 hours 23 minutes on type. He also had about 150 hours and 800 landings in powered flight. Nothing suggested he was in poor health. Records showed no prior accidents or incidents.
Aircraft Information
The Rhönlerche II HB-592 was certified for flight. The investigation found no evidence of a mechanical defect as a cause. The total weight was 6 kg above the maximum allowable 400 kg; the center of gravity was within limits.
Meteorological Conditions
Local weather: wind southwest 10–20 knots at ground level, west-southwest at 1,500 meters, visibility 10–15 km, local showers, turbulence.
Analysis
The student pilot, considering the prevailing wind, stopped spiraling and began a relatively high approach. However, his mistaken belief about the active runway led to a loss of time and altitude, resulting in insufficient altitude during the final approach despite the shortened circuit during the base turn. The dive performed by the instructor in the final phase of the flight was unnecessary.
The accident could have been avoided by a second timely intervention by the instructor.
Probable Cause
The accident was due to a late intervention by the instructor during a final approach conducted at insufficient altitude after an error in the circuit flown by the student pilot.