What happened
On 11 January 2021, a pilot operating a Safari LSA, registration ZU-IJZ, departed from Kroon Airfield in Gauteng province for a series of touch-and-go landing exercises. The flight was intended to proceed to Bundu Airfield before returning to the departure point.
During the takeoff roll, the pilot rotated at 60 mph and established a climb at 65 mph. However, as the aircraft reached approximately 50 feet above ground level, the engine began to lose power. While engine temperature and pressure readings remained within normal parameters, the pilot observed a drop in boost pressure. In an attempt to maintain airspeed, the pilot leveled the aircraft, but the speed continued to decay below 60 mph. Despite applying half flaps to prevent a stall, the pilot was unable to recover the necessary airspeed and decided to perform a precautionary landing on a nearby gravel road.
As the aircraft approached the landing site, it stalled, causing the left wing to drop. During the touchdown on the road, the left main landing gear struck a sand ridge left by a road grader. This impact caused the aircraft to veer left off the road and come to rest on an embankment. The aircraft suffered substantial damage to the fuselage, tail, and wings, while the pilot escaped with minor injuries.
The investigation
SACAA AIID investigators examined the aircraft's maintenance history and mechanical condition. Records showed the aircraft had undergone a mandatory maintenance inspection in August 2020 and had recently undergone repairs to the turbo boost system in December 2020. The investigation confirmed the pilot was properly licensed and medically fit for the flight.
Post-accident testing of the boost system, including the wastegate cycle operation, revealed no mechanical abnormalities or defects. The pilot was also found to have executed emergency procedures in accordance with the Rotax Pilot Operating Handbook (POH) by leveling the aircraft and selecting a suitable landing area.
Findings
- The engine experienced a loss of power during the initial climb phase.
- The pilot observed a drop in boost pressure despite normal temperature and pressure readings.
- The aircraft stalled immediately prior to touchdown on the gravel road.
- The left main landing gear struck a sand ridge, leading to the loss of directional control.
- The fuel pressure regulator likely failed, causing fuel pressure to drop below 0.25 bar, which prevented the engine from receiving sufficient fuel to maintain power.