What happened
On 11 February 2001, a Cessna R182, registration ZS-NXN, was preparing for a private flight from Henneman Aerodrome to Kimberley. The aircraft was carrying the pilot and three passengers. During taxiing toward the runway 15 holding point, the pilot observed a track crossing the grass runway about one-third of the way down the strip. To avoid potential undercarriage damage from this track, the pilot elected to begin the takeoff roll from that point onward.
As the aircraft reached a speed of approximately 50 knots, the pilot determined that the remaining runway length was inadequate for a safe takeoff. Furthermore, the presence of glider activity in the area necessitated a safe stopping distance, which the remaining pavement could not provide. In an attempt to abort the takeoff, the pilot steered the aircraft to the left of the runway, which resulted in a collision with the aerodrome perimeter fence. The aircraft eventually came to a stop roughly 20 meters beyond the impact point. There were no fatalities and no injuries reported among the occupants.
The investigation
Investigators examined the aircraft's weight and performance requirements relative to the environmental conditions. The takeoff weight was 2,918.6 lbs, which was within the manufacturer's limits. However, the density altitude was calculated at 6,000 feet due to the aerodrome elevation of 4,300 feet and a temperature of +20°C.
According to the pilot's operating handbook, a takeoff distance of 2,400 feet was necessary to clear a 50-foot obstacle. Because the runway was a grass surface, an additional 15% distance was required, bringing the total necessary runway length to approximately 2,760 feet. The investigation focused on the pilot's decision to use a truncated portion of the runway.
Findings
- The pilot underestimated the required takeoff distance due to the decision to start the roll past the runway track.
- While the pilot intended to protect the aircraft's undercarriage, the reduced available runway length was insufficient for the calculated performance requirements under the prevailing density altitude and grass surface conditions.