What happened
On 4 April 2018, a Bellanca Citabria 7ECA, registration ZS-WLI, was performing a private flight originating from Fly Inn Estate. After a successful initial landing and taxi at Rhino Park Airfield, the pilot attempted a takeoff from runway 27. During the takeoff roll, the aircraft reached approximately 45 mph when the engine began running rough and the RPM dropped significantly from 2,45 and to 2,000.
Unable to reach the required rotation speed of 55 mph, the pilot elected to abort the takeoff. However, the aircraft was already three-quarters down the 800m runway. Despite the application of brakes, the aircraft could not stop within the remaining distance. The brakes locked, causing the plane to skid across the runway and onto a muddy surface, eventually coming to rest in a ditch roughly 85 m from the threshold of runway 09. The impact resulted in two serious injuries and substantial damage to the aircraft's propeller, engine cowlings, windshield, main landing gear, and left-hand wing.
The investigation
SACAA AIID investigators examined the aircraft's performance capabilities and the environmental conditions at the time of the accident. The investigation confirmed that the aircraft required between 538 and 640 m for takeoff at the ambient temperature of 20°C, and approximately 300m to come to a complete stop. Because the engine power loss occurred so far down the runway, there was insufficient distance remaining to execute a safe stop.
Technical reviews of the aircraft's maintenance records showed the plane had undergone an annual inspection less than one hour prior to the accident. The investigation also analyzed the meteorological data, noting a temperature of 21°C and a dew point of 15°C. Using a carburetor icing probability chart, investigators determined that the atmospheric conditions presented a moderate risk of icing during cruise power and a serious risk during descent power.
Findings
- The engine experienced a partial power loss during the takeoff roll.
- The pilot attempted an aborted takeoff, but the remaining runway length was insufficient to stop the aircraft.
- The aircraft skidded on a muddy surface after exiting the runway.
- The engine performance was likely compromised by carburetor icing, which may have accumulated during taxiing at the airfield.