No fatalities

22 Aug 2019: Grob G103 TWIN II — San Antonio Soaring Society Inc — San Antonio, TX

San Antonio, TX, United States

On 22 Aug 2019, a Grob G103 TWIN II operated by San Antonio Soaring Society Inc was involved in an aviation accident near San Antonio, TX. No fatalities were reported. Investigators recorded the probable cause as: 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. 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 pilot reported rear canopy opening at 3,000 ft, followed by an uncontrollable spin and front canopy failure. After regaining control, the pilot made an off-airport landing. Tow rope was found entangled in the rudder.

Incident Sequence

While being towed and approaching 3,000 ft above ground level, the glider pilot reported that the rear canopy opened. The pilot informed the tow airplane via radio about the open canopy. In response, the tow pilot indicated that he would attempt to tow the glider closer to the runway. Shortly afterward, the glider entered an uncontrollable downward spin, during which the front canopy shattered. The pilot managed to regain control of the glider and noted that the rear canopy had separated from the aircraft. He then made an extended right base leg and prepared for an off-airport landing. The pilot reported that the flight controls were not responding properly, and the glider landed hard on the runway.

Post-Accident Findings

After the accident, the pilot discovered that a section of the tow rope was still connected to the glider. This rope section had become wrapped and inserted into the rudder mechanism. Photographs obtained from FAA Inspectors indicated that the tow rope exhibited overload signatures. Additionally, each aircraft (the tow airplane and the glider) still had a portion of the tow rope attached following the rope failure.

Aircraft Damage

The glider sustained substantial damage to its composite fuselage.

Contributing factors

Causes

Aerial tow equipment section — FailureEquipment/furnishings — Failure

Other contributing factors

Pilot