What happened
On May 3, 2014, at approximately 12:10 MST, an experimental exhibition racing glider sustained substantial damage after impacting terrain during a takeoff climb from Sampley's Airport (28AZ) in Aguila, Arizona. The aircraft, registration N22DA, was being towed by a tow plane when the separation occurred.
The tow pilot reported a normal takeoff, but shortly after beginning the climb, he noticed a lightening of the control forces. The pilot then determined that the glider had separated from the tow line at an altitude of approximately 100 feet above ground level. The tow plane pilot circled the area and located the wreckage about 300 feet to the left of the runway and roughly 180 degrees off the runway heading. The pilot of the tow plane landed the aircraft uneventfully.
The pilot of the glider, a 61-year-old commercial pilot, sustained 1 fatal injury.
The investigation
Investigators examined the accident site and found the glider had impacted the terrain at a high-impact angle consistent with a loss of control. The aircraft came to rest inverted, with debris including canopy fragments and a wing section located within a 30-foot path.
An examination of the tow airplane's tow line, connection, and release mechanism showed no anomalies. However, a detailed analysis of the glider's cable release control system at the NTSB Materials Laboratory revealed that a missing spring was present. Investigators found a recess that appeared to be a retaining hole for a spring, but there was no evidence of a spring having been in contact with the housing interior surfaces. This absence of the spring likely prevented the cable from properly engaging in the detent.
No historical maintenance records for the glider could be located. Post-accident examination of the airframe and the remaining components revealed no other mechanical failures that would have prevented normal operation.