What happened
On 23 September 2006, a private flight was underway from Wonderboom Aerodrome to Pyramid Aerodrome. During the landing roll on Runway 30, the pilot of the Jabiru J430, registration ZU-EFW, experienced an unexpected deceleration. Although the pilot had not applied the brakes, the aircraft began to brake involuntarily. As the airspeed dropped to roughly 20 knots, the tail plane lifted slightly, causing the propeller to strike the ground. The impact caused the propeller to break off and the engine to stop. The aircraft eventually settled on all three wheels, and the pilot escaped the incident without injury.
The investigation
Investigators examined the aircraft following the incident to determine why the braking occurred without pilot input. The inspection focused on the nose gear assembly and the condition of the runway surface, which was covered in grass. The investigation also reviewed the aircraft's maintenance history, noting that the most recent 25-hour inspection had been completed on 14 August 2006, with 20.2 flying hours logged since that service.
Findings
Technical analysis revealed that the nose wheel spat had dislodged, moving into a position where it interfered with the rotation of the nose wheel. This mechanical obstruction prevented the wheel from turning properly, causing it to slide across the grass-covered runway. As the restricted wheel began to dig into the soft ground, the resulting resistance forced the tail plane upward, directly leading to the propeller making contact with the earth.