What happened
On 21 August 2018, a private pilot and two passengers were conducting a cross-country flight from Wonderboom Aerodrome, intended to include stops at Rustenburg and Thabazimbi. Upon arriving at Rustenburg Aerodrome (FARG), the pilot opted for a touch-and-go maneuver on runway 34.
Following touchdown, the pilot noted the shimmy damper was active for approximately five seconds. During this period, the pilot delayed applying full power, which consumed an additional 547 feet of the available runway. When the pilot eventually applied power and attempted to rotate the aircraft at 60 knots, the aircraft failed to achieve a positive rate of climb. Attempting to abort the takeoff, the pilot landed back on the remaining runway surface, but the aircraft could not be stopped within the remaining distance. The Cessna 17/2N, registration ZS-OHN, overran the runway, breached the aerodrome perimeter fence, and came to rest on a pile of rubble near an informal settlement. The three occupants sustained minor injuries, while the aircraft suffered substantial damage.
The investigation
SACAA AIID investigators examined the aircraft's weight and balance records and found significant discrepancies in the pilot's calculations. The investigation established that the pilot used an unapproved weight and balance chart and utilized incorrect figures for both the aircraft's empty weight and the passengers' mass. Specifically, the pilot recorded the passengers' weight as 136 kg, whereas the actual weight was 188 kg.
Furthermore, the investigation noted that the aircraft was operating in high density altitude conditions (6,210 ft), which required a nearly 91% increase in takeoff distance. The pilot also failed to utilize the training organization's electronic flight authorization system, which would have provided a warning regarding the exceedance of operating limits. Consequently, the aircraft was operating above its maximum takeoff weight, with an estimated weight of approximately 2,325 lb against a limit of 2,300 lb.
Findings
- The primary cause of the accident was a premature rotation of the aircraft, which prevented the establishment of a positive rate of climb.
- The aircraft was significantly overweight during both the landing and the attempted takeoff at Rustenburg Aerodrome.
- The pilot relied on inaccurate weight and balance data and an unapproved calculation method.
- High density altitude at the time of the accident significantly increased the required takeoff distance.