No fatalities

19 Jun 2009: GROB G103 TWIN II — Wellington, CO

Wellington, CO, United States

On 19 Jun 2009, a GROB G103 TWIN II was involved in an aviation accident near Wellington, CO. No fatalities were reported. Investigators recorded the probable cause as: The pilot’s failure to maintain control of the glider during takeoff. This summary draws on records from NTSB; 6 related events involving the same aircraft type or operator are linked below.

SourcesNTSBPrimary reportUpdated 1778583330Data APIEditorial standards

A glider experienced a stall and impacted terrain after a premature takeoff in wind gusts and thermals, resulting in partial empennage separation. No mechanical anomalies were found.

Accident Summary

A glider pilot reported that the initial takeoff roll proceeded normally. However, after a premature takeoff initiated due to wind gusts and thermals, the glider's controls became ineffective. The pilot attempted to release the tow line by pulling the release knob, but the tow line “back-released,” leading to a stall. The glider subsequently impacted the terrain, causing partial separation of the empennage just aft of the fuselage.

Sequence of Events

According to the pilot, the takeoff roll began without issue. The decision to take off prematurely was made in response to wind gusts and thermal conditions. Shortly after becoming airborne, control effectiveness was lost. The pilot's action to release the tow line resulted in a back-release, and the glider entered a stall. The descent ended with the aircraft striking the ground, damaging the empennage.

Wreckage Examination

An examination of the tow line release mechanism and other glider systems revealed no mechanical anomalies. The release system functioned as designed, and no preexisting faults were identified that could have contributed to the sequence of events.

Contributing factors

PilotPerformance/control parameters — Not attained/maintained