What happened
On 26 May 2015, a private flight departed from Springs Aerodrome (FASI) in Gauteng. The pilot, intending to honor a friend who had recently died in a similar aircraft accident, had modified the Aerotrike Scout, registration ZU-FKS, by attaching a memorial banner to the aircraft. The flight was intended to be a brief, five-minute mission.
During the takeoff roll, the aircraft began a right-hand turn. As the microlight transitioned, the wind caught the attached banner, significantly altering the aircraft's aerodynamic profile. This disturbance caused the left wing to stall, triggering a sudden nose-down pitch. The aircraft entered a violent spiral dive and a full-loop sequence before impacting the grass at the intersection of runways 03/21 and 14/32. The impact was nose-first, resulting in one fatality.
The investigation
SACAA AIID investigators examined the wreckage and reviewed video footage recorded by a camera mounted on the aircraft's right wing. The footage captured the exact moment the wind pushed the banner upward, destabilizing the wing. The investigation also reviewed the pilot's maintenance records and the aircraft's technical specifications. It was noted that the aircraft's maintenance certificate had lapsed prior to the accident. The investigation focused on the interaction between the wind, the modified banner, and the specific flight characteristics of weight-shift-controlled (WSC) aircraft.
Findings
- The primary cause of the accident was the unapproved banner modification, which changed the aerodynamic characteristics of the aircraft.
- The aircraft experienced a whip stall followed by a tuck/tumble phase, a state from which recovery was impossible.
- The pilot's disregard for standard operational procedures contributed to the sequence of events.
- The wind component during takeoff interacted with the banner to create an unstable flight condition.