Probable cause
The failure of the glider tow rope, which lodged in the glider's rudder and resulted in a hard landing. Contributing to the accident was the pilot's failure to properly secure the glider's aft canopy.
NTSB analysis
The glider pilot reported that, while being towed and approaching 3,000 ft above ground level, the glider's rear canopy opened. The glider pilot informed the tow airplane pilot via radio that the canopy had opened, and the tow airplane pilot informed the glider pilot that he would try to tow the glider closer to the runway. Shortly after, the glider entered an uncontrollable downward spin, and the front canopy shattered. The pilot regained control of the glider, and the rear canopy separated from the glider. The glider pilot made an extended right base and prepared for an off-airport landing. The flight controls were not responding properly, and the glider landed hard on the runway. The pilot reported that, after the accident, he found a section of the tow rope still connected to the glider and lodged in the rudder mechanism. A review of photographs of the airplane revealed that the tow rope exhibited overload signatures. Each airplane still had a portion of the tow rope attached to it after the tow rope failed. The glider sustained substantial damage to the composite fuselage.
Text from the NTSB. Open the NTSB docket for GAA19CA506 for the full record.
Event
- Date
- Aug 22, 2019
- Type
- Accident
- Place
- San Antonio, Texas
- Nearest airport
- Boerne Stage Field (5C1)
- Highest injury
- None
- Weather
- Visual (VMC)
- Light
- Day
Grob G103
- N-number
- N901BG
- Category
- Glider
- Year built
- 1981
- Damage
- Substantial
- Operating rule
- Part 91 (general aviation)
- Purpose of flight
- Glider tow
From the NTSB aviation accident database: N-registered aircraft, events since 2008, data through Oct 28, 2026. The file is published monthly, so the latest weeks are incomplete and recent records can change. The official source is the NTSB aviation investigation search. CheckAero is independent and not affiliated with the NTSB.