What happened
On 4 January 2003, a PIPER PA 25-235, registered as ZS-NVF, was engaged in a banner-towing mission departing from Stellenbosch. After refueling the aircraft to its maximum capacity, the pilot proceeded toward the Green Point area of Cape Town. While cruising at approximately 300 ft AGL near Camps Bay, the aircraft encountered turbulence that caused it to fly inverted. Although the pilot successfully righted the aircraft and attempted to return to Stellenbosch, the engine began to run roughly. The engine power steadily declined until a total failure occurred, forcing the pilot to perform an emergency landing on an open field adjacent to the Hamilton Sports Field. To prevent potential injury to people on the ground, the pilot chose not to release the banner during the descent. The pilot sustained serious injuries, and the aircraft suffered extensive damage.
The investigation
SACAA AIID investigators examined the mechanical state of the aircraft and the environmental conditions at the time of the incident. Meteorological reports indicated clear skies but noted significant wind speeds of 15 to 20 knots, with gusts reaching 30 knots. The investigation confirmed that the aircraft was properly maintained and type-accepted for use in South Africa. A post-accident inspection of the engine, which included a full dismantling, revealed no mechanical abnormalities or defects that could have caused the power loss, other than damage sustained during the impact. The investigation also noted that while the pilot held a valid commercial license and medical certificate, they lacked the specific rating required for banner-towing operations.
Findings
Several factors contributed to the engine failure and subsequent forced landing:
- Increased fuel consumption caused by high-velocity, gusty winds and the significant aerodynamic drag produced by the banner.
- The pilot's lack of a specific rating for banner towing, which may have led to errors in calculating fuel requirements and managing aircraft maneuverability.
- The low altitude of 300 ft AGL, which severely restricted the pilot's available options once the engine failed.
- The decision to retain the banner during the emergency, which prevented a release that might have altered the landing profile.