What happened
On 23 March 2013, a chartered Bell 206B helicopter, registration ZS-HSR, was performing a domestic flight to transport four passengers to an ad hoc landing site near the Pietermaritzburg Botanical Gardens for a wedding. The flight departed from Pietermaritzburg Airfield after relocating from its base at Virginia Airfield.
During the approach to the landing site, the pilot was executing a right-hand pattern at approximately 500 feet AGL. While orbiting, the aircraft encountered wind shear and a sudden loss of approximately 50 feet in altitude. The pilot attempted to recover by reducing power and lowering the nose to increase airspeed; however, these actions failed to arrest a rapid descent and an increasing rightward yaw. The aircraft entered a spin and impacted the ground near Zwartkop Street. The initial impact occurred on one side of the street, with the momentum of the crash forcing the wreckage across to the opposite side near the botanical gardens. The impact caused substantial damage to the aircraft, including the shearing of the main rotor from the mast, while the pilot and four passengers sustained various injuries, ranging from minor to severe.
The investigation
SACAA AIID investigators examined the wreckage and the flight history of the aircraft. Technical inspections by engineers from both Bell Helicopters and Rolls Royce confirmed that the engine and airframe were in good condition prior to the accident, with no evidence of pre-existing defects, metal fatigue, or unserviceable components. The investigation found that the aircraft's maintenance records were up to date and the pilot was properly qualified and medically fit. The investigation also noted that the landing site had been officially approved by the SACAA prior to the flight.
Findings
- The primary cause of the accident was the loss of tail rotor effect (LTE), triggered by the pilot performing a right turn during an approach at low airspeed.
- The presence of a tailwind (18 knots from 160°) exacerbated the aircraft's tendency to yaw to the right.
- The pilot's recovery attempts—reducing power and lowering the nose—were counterproductive due to the low altitude and high rate of descent.
- Poor in-flight planning was identified as a contributing factor to the loss of control.