What happened
On 25 September 2014, a Robinson R44 Raven II helicopter, registration ZS-OFJ, was conducting a commercial vehicle tracking flight near Rand Airport. The aircraft, operated by Henley Air, was returning to the airport with the pilot and one passenger on board. While approaching the airfield, the pilot requested permission to cross Runway 2lar 29, but was denied by Air Traffic Control (ATC) due to active training traffic on the runway. The pilot was instructed to remain north of the runway and report once safely on the ground.
During the maneuver to comply with these instructions, the aircraft was observed by ATC hovering over an industrial area in Germiston. The controller noted the helicopter performing unusual movements, specifically a sudden pitch upward followed by a sharp nose-down dive. The pilot issued an emergency "MAYDAY" call, and an audible low rotor RPM warning was heard over the radio. An eyewitness reported seeing the aircraft fall in a nose-down attitude before impacting a dumping site, where the wreckage immediately burst into flames. The impact resulted in 2 fatalities.
The investigation
SACAA AIID investigators examined the wreckage, maintenance records, and ATC communications. The investigation confirmed that the Robinson R44 Raven II had been properly maintained and was within weight and balance limits at the time of the accident. The investigation also reviewed the pilot's training history, noting that while she was a qualified commercial pilot, this was her first day of flight operations with her new employer and her first time operating in this specific northern region.
Investigators analyzed the flight path and environmental conditions, noting that the aircraft was flying with a tailwind component. The wreckage distribution was localized within a 40-meter radius, and the damage to the main rotor was consistent with high power settings at the moment of impact. The investigation also reviewed the pilot's recent training, which had primarily taken place in a different geographic area, potentially affecting her familiarity with the local approach procedures.
Findings
- The primary cause of the accident was that the helicopter entered a vortex ring state from which the pilot could not recover.
- The pilot attempted a sudden "quick stop" maneuver to transition into an out-of-ground effect (OGE) hover to reorient herself, which induced the settling with power.
- The maneuver was performed at a restricted height of approximately 600 feet AGL, leaving insufficient altitude for recovery.
- The presence of a tailwind component contributed to the onset of the vortex ring state during the sudden deceleration.
- A loss of situational awareness regarding the aircraft's position relative to the ATC instructions led to the risky maneuvering.