What happened
On 13 September 2011, a Bell 230 helicopter, registration ZS-HMP, was conducting a charter flight from Megawatt Park to the Naledi substation near Groblersdal. The flight carried the pilot and five passengers. Upon arriving at the destination, the pilot evaluated the landing zone, which included a soccer field and a nearby grass area.
As the aircraft descended toward the soccer field, the rotor wash kicked up significant amounts of dust from the ground. Although a water bowser had been used to dampen the area beforehand, the moisture was insufficient to suppress the dust. This created a severe brownout condition, drastically reducing the pilot's visibility. During this period of disorientation, the helicopter's main rotor blades struck an electrical pole. The aircraft subsequently hit the ground and rolled onto its side. The occupants managed to evacuate the cabin immediately, but the helicopter was destroyed by a post-impact fire. All 6 occupants sustained minor injuries.
The investigation
SACAA AIID examined the wreckage, the site, and witness statements from both passengers and ground personnel. The investigation confirmed that the aircraft was properly maintained and had a valid certificate of airworthiness. There was no evidence of mechanical malfunction or engine failure prior to the collision. Investigators also noted that while the weather was clear, the localized environmental conditions created by the dust were the primary concern. The investigation also looked into the effectiveness of the dust suppression efforts, finding that the water applied to the field was inadequate to prevent the brownout.
Findings
- The pilot was properly licensed with the necessary type ratings and a valid medical certificate.
- The operator held a valid operating certificate, and the aircraft was in a state of airworthiness.
- The primary cause of the accident was the reduced visibility caused by a brownout during the landing approach.
- The helicopter made contact with an electrical pole due to the loss of visual reference, leading to the subsequent ground impact and fire.