What happened
On 30 April 2012, a Schleicher ASW 24 glider, registration G-CGDU, was involved in a fatal accident near Dunstable, Bedfordshire. The pilot was performing a winch launch, which is a method of launching gliders without a tow plane. After reaching an altitude of approximately 900 ft, the aircraft followed the Dunstable Downs ridge before the pilot executed a steep, wings-level climb.
Following this pull-up, the aircraft banked to the left. Witnesses observed the glider entering a spiral dive to the right. The aircraft subsequently impacted a field of crops in a steep, nose-down attitude. The pilot sustained fatal injuries in the crash, and the aircraft was destroyed.
The investigation
Investigators examined the wreckage and found the aircraft was structurally intact prior to impact, with the landing gear retracted and airb/rakes closed. No mechanical failures or control issues were identified.
Data recovered from two GPS receivers provided critical insights into the flight path. The analysis of the GPS altitude and groundspeed indicated that during the level-off following the steep climb, the aircraft's airspeed dropped significantly. Given the wind conditions—a south-easterly wind of 14 kt with gusts up to 24 kt—the glider's groundspeed was approximately 47 kt. This placed the airspeed very close to the 1g stall speed for the aircraft's weight.
Findings
- The aircraft was in a right-hand spiral dive at the moment of impact.
- The pilot performed a pull-up manoeuvre, possibly to exploit rising air, which caused a significant reduction in airspeed.
- The combination of low airspeed and a strong tailwind component resulted in the aircraft reaching a state of stall and loss of control.
- There was insufficient altitude remaining to perform a recovery from the resulting spiral dive.