Introduction
On 19 January 2025, a Cessna A188B Ag Truck, registration ZS-KDX, was involved in an accident during take-off from Mokopane Airfield (FAQR) in Limpopo Province, South Africa. The flight was conducted under visual meteorological conditions (VMC) by day and under Part 137 of the Civil Aviation Regulations (CAR) 2011.
Occurrence
The pilot, holding a valid Commercial Pilot Licence (CPL) and Class 1 medical certificate, had completed two crop-spraying flights earlier that day. The first flight lasted 30 minutes, followed by a second flight of 4.9 hours. After landing at 1500Z, the pilot conducted a pre-flight inspection, loaded 600 litres of crop-spraying chemical, and uplifted 100 litres of Aviation Gasoline (AVGAS). At approximately 1515Z, during the take-off run on Runway 36 with a reported 5-knot north-easterly wind, about 575 metres from the runway threshold, a gust of wind from the left lifted the left wing, causing the aircraft to veer right. The propeller and right wing struck the ground, bending the propeller blades. The aircraft ground-looped clockwise and came to rest on the right side of the runway. The pilot was not injured.
Aircraft Damage
The aircraft sustained substantial damage, including a rippled and bent left wing, bent propeller blades, and separation of the empennage and tail from the fuselage.
Meteorological Information
At the time of the accident, wind direction was from the northeast at 5 knots, visibility 10 km, temperature 25°C, dew point 15°C, cloud cover few, QNH 877.2 hPa. The aircraft's crosswind component limitation is 15 knots; the calculated crosswind component was 3.5 knots, not deemed significant to affect stability.
Post-accident Investigation
Mokopane Airfield is surrounded by mountainous terrain. The pilot reported a sudden change in wind direction and speed during take-off, leading to loss of control. The weather condition could have been a result of mountain waves, defined as oscillations to the lee side of high ground causing turbulence and strong vertical currents.
Findings
- The pilot was properly licensed and qualified, with a CPL issued in 1993 and renewed in August 2024, and a valid Class 1 medical certificate.
- The aircraft had a valid Certificate of Airworthiness and was properly maintained; the last mandatory periodic inspection was in August 2024.
- The airfield is surrounded by mountainous terrain, and it is likely the aircraft was affected by mountain waves during take-off.
Probable Cause
Loss of directional control during take-off, with mountain waves as a contributing factor.
Safety Actions
The operator at this airfield should issue a safety notice to ensure all pilots are aware of the dangers associated with mountain waves.