Fatal Glider Crash at New Tempe Following Tow Rope Failure

Casualties unknown • In an open field about 2 NM from New Tempe Airport, ZA

A heavily ballasted JS 1C 18/21 glider crashed near New Tempe Airport after the tow rope snapped, resulting in the death of the pilot.

What happened

On 20 January 2014, a JS 1C 18/21 glider, registration ZS-GBF, was participating in an aero-tow operation at New Tempe Airport, Free State. The flight was being conducted under private operations, with the pilot intending to attempt a national record. The aircraft was heavily loaded with water ballast in the wing and tail tanks for the flight.

During the initial climb phase, the tug aircraft, a Cessna 1t82, initiated a gentle left turn. Witnesses observed the glider drifting out of its proper position behind the tug. As the glider moved out of alignment, the tension on the tow rope increased significantly. This sudden load caused the tow rope to fail. Following the break, the glider experienced a sharp yaw to the left and rolled into a steep, nose-down dive. Due to the low altitude and the high momentum of the water-ballasted aircraft, the pilot was unable to recover from the dive, and the aircraft impacted the ground in an open field approximately 2 NM from the aerodrome. The accident resulted in one fatality.

The investigation

SACAA AIID investigators examined the wreckage and interviewed several witnesses, including the tug pilot and ground personnel. The investigation focused on the condition of the tow rope and the aircraft's stability. Physical examination of the ZS-GBF revealed that the cockpit was destroyed and the tail boom had snapped. Evidence showed that the wing tanks were filled with water at the time of impact.

Testing of the tow rope revealed extensive scuffing damage along its length, likely caused by improper handling or frequent dragging on hard surfaces. This damage had weakened the rope, making it unable to withstand the sudden tension spike. Furthermore, the investigation found that the aircraft's center of gravity was 5mm behind the allowable limit due to the specific distribution of the water ballast, which contributed to pitch instability.

Findings

  • The glider moved out of position during the climb, failing to follow the tug aircraft's turn.
  • The tow rope broke due to excessive tension caused by the glider's displacement.
  • The tow rope was in a fragile state due to progressive scuffing damage from improper handling.
  • The aircraft's center of gravity was outside the allowable range, which may have increased pitch instability.
  • The pilot failed to release the tow hook when the aircraft moved out of position and was unable to recover from the resulting dive.

Probable cause

The primary cause of the accident was the failure of the tow rope under sudden, excessive load when the glider drifted out of position behind the tug aircraft. This was exacerbated by the rope's pre-existing structural degradation from scuffing and the aircraft's unstable center of gravity caused by heavy water ballasting.

Frequently asked questions

What happened in the 2014-01-20 Glider JS 1C 18/21 accident near In an open field about 2 NM from New Tempe Airport, ZA?

A heavily ballasted JS 1C 18/21 glider crashed near New Tempe Airport after the tow rope snapped, resulting in the death of the pilot.

What aircraft was involved and where did it happen?

The accident on 2014-01-20 involved a Glider JS 1C 18/21, registration ZS-GBF, at In an open field about 2 NM from New Tempe Airport, ZA.

What was the probable cause of the accident?

The primary cause of the accident was the failure of the tow rope under sudden, excessive load when the glider drifted out of position behind the tug aircraft. This was exacerbated by the rope's pre-existing structural degradation from scuffing and the aircraft's unstable center of gravity caused by heavy water…

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