What happened
On June 14, 2009, a Burkhart Grob G103C Twin III Acro glider, registration N103MS, crashed near Gregory, Michigan, during a flight conducted under 14 CFR Part 91. The flight, operated by the Sandhill Soaring Club, departed from Richmond Field Airport (69G) using a ground-based winch for takeoff.
During the initial climb, approximately 400 feet above ground level, the winch cable snapped. The pilot responded by lowering the nose to maintain a speed of at least 60 knots and proceeded with an upwind pattern to prepare for a 180-degree right turn toward the landing area.
The pilot reported that while executing the turn, the aircraft's handling changed unexpectedly, though no signs of a stall were initially observed. Before any corrective action could be taken, the nose dropped abruptly, sending the aircraft into a dive toward the intended runway. The glider impacted the ground in a nose-down, right-bank attitude. The collision resulted in 1 fatal injury to the passenger and 1 serious injury to the pilot.
The investigation
Investigators examined the wreckage and found the cockpit area destroyed and the nose section embedded in the ground. While the wings remained attached to the fuselage, the right wing exhibited a gap at the trailing edge. The empennage separated from the aft fuselage, with the separation of the elevator and rudder push-pull tubes appearing consistent with overload forces from the impact.
Post-accident inspection of the flight controls confirmed continuity from the control surfaces to the aft cockpit stick, with no anomalies found that indicated a pre-impact mechanical malfunction of the glider's controls.
A metallurgical examination of the winch cable was performed. The analysis of the cable revealed features, including "cup and cone" fracture surfaces and necking of the wire, which are characteristic of an overstress fracture.