Engine Power Loss Leads to Ultralight Collision with Power Lines

Casualties unknown • Next to R103 road, Estcourt, ZA

A Windlass Trilight aircraft crashed near Estcourt after an engine failure caused it to strike high-tension wires during low-altitude flight.

What happened

On 20 November 2010, a private flight departing from Harrismith Aerodrome encountered a critical emergency near Estcourt, KwaZulu-Natal. The pilot, flying a Windlass Trike registration ZU-BID, had diverted from his original route to visit a friend's farm. After circling the property at an altitude of approximately 40 feet AGL to greet the resident, the aircraft began flying toward a nearby road.

During this low-level maneuver, the aircraft's engine suffered a sudden loss of power. While descending at approximately 150 feet AGL, the aircraft struck high-tension power lines. The impact caused a momentary disruption to the local electricity supply. The aircraft's left main gear collided with the wires, and the wing subsequently struck a tree before the aircraft impacted the ground in a nose-down attitude. The pilot sustained broken ribs and a punctured lung, while the passenger suffered minor injuries. The aircraft was substantially damaged.

The investigation

SACAA AIID investigators examined the wreckage and conducted a detailed engine teardown inspection. The investigation focused on the mechanical state of the Rotax engine and the circumstances of the low-altitude flight. Investigators also reviewed maintenance records and interviewed a witness, the farmer who had seen the aircraft circling moments before the crash.

Findings

  • The engine teardown revealed several mechanical discrepancies, including a misaligned timing position and a trigger gap set at 0.3mm, which fell below the manufacturer's required specification of 0.4mm to 0.5mm.
  • A crack was identified on one of the carburetor intake sockets.
  • The ignition coil protection caps were found to be degraded, leaving the system vulnerable to moisture.
  • The propeller assembly was found to be improperly configured, utilizing blades with non-matching serial numbers, which could cause severe vibration or loss of thrust.
  • The pilot was operating the aircraft at a very low altitude (approximately 150 feet AGL) when the power loss occurred, leaving insufficient margin to clear the 20-foot high power lines as the terrain rose.
  • Maintenance of the engine was not performed in accordance with the manufacturer's specifications.

Probable cause

The aircraft suffered a loss of engine power during low-altitude flight, resulting in a collision with high-tension wires and a subsequent ground impact.

Frequently asked questions

What happened in the 2010-11-20 Windlass Trike accident near Next to R103 road, Estcourt, ZA?

A Windlass Trilight aircraft crashed near Estcourt after an engine failure caused it to strike high-tension wires during low-altitude flight.

What aircraft was involved and where did it happen?

The accident on 2010-11-20 involved a Windlass Trike, registration ZU-BID, at Next to R103 road, Estcourt, ZA.

What was the probable cause of the accident?

The aircraft suffered a loss of engine power during low-altitude flight, resulting in a collision with high-tension wires and a subsequent ground impact.

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