What happened
On 31 October 2022, a pilot was operating a private flight from Nieu-Bethesda Airfield in the Eastern Cape toward Eagle’s Creek Aerodrome in Gauteng. The flight, conducted under Part 94 regulations, involved the Ekolot KR-030 Topaz, registration ZU-EWZ, flying in loose formation with another light-sport aircraft.
While flying near the Gariep Dam at approximately 6,500 feet, the pilot noticed a minor vibration in the propeller. This vibration intensified as the flight progressed. In an attempt to manage the issue, the pilot reduced engine power, but this resulted in a loss of altitude. Upon attempting to increase power to regain height, the vibration worsened, forcing the pilot to prepare for an emergency.
While on final approach to New Tempe Aerodrome (FATP), the engine was set to idle power. Realizing the aircraft would not reach the runway, the pilot performed a forced landing on uneven terrain approximately 90 meters from the threshold of Runway 2GB. During the landing, the nose gear strut collapsed after the wheel dug into the soft ground, resulting in substantial damage to the Ekolot KR-030 Topaz. The pilot escaped without injury.
The investigation
SACAA AIID investigators examined the wreckage and the aircraft's technical records. The engine and its components, including the vibration mounts and the reduction gearbox, were found to be in good condition. The chip detector showed no metallic debris.
An analysis of the three-blade propeller revealed that while one blade was undamaged, the other two had nicks from stones. Specifically, investigators found that a portion of the third blade tip had fractured. The investigation determined that this fracture likely occurred when the blade struck a stone during takeoff from the gravel runway. The structural integrity of the blade was subsequently compromised, leading the tip to separate due to centrifugal forces during the flight.
Findings
- The aircraft was operating from a gravel runway.
- A stone was likely kicked up by the propeller wash during takeoff, striking the propeller blade.
- The impact caused a fracture in the tip of the third propeller blade.
- Centrifugal forces caused the weakened blade tip to separate during the flight, creating the vibrations that led to the forced landing.