History of Flight
On 25 October 2019, a Robinson R44 helicopter, registration ZT-RAL, took off from Wonderboom Aerodrome (FAWB) in Gauteng Province, South Africa, for a training flight conducted under Part 141. On board were three pilots: a designated flight examiner (DFE) acting as instructor, a pilot undergoing instrument rating revalidation, and an authorised officer (AO) from the South African Civil Aviation Authority's personnel licensing department. The flight involved simulated instrument let-down, practice autorotation, and simulated confined landing exercises, all completed successfully.
After the exercises, the pilot under test initiated an approach to the landing area in front of the operator's hangar. The DFE, dissatisfied with the approach, took over controls and initiated a climb in a south-easterly direction. At approximately 200 feet above ground level (AGL) and 40 knots indicated airspeed, the low rotor RPM warning horn sounded briefly and a caution light illuminated; the DFE corrected by reducing collective pitch. At about 300 feet AGL, while turning right toward the runway threshold, the low rotor RPM warning horn sounded again and remained on, with a caution light illuminated. Attempts to recover by reducing collective had no effect.
Due to insufficient height for autorotation and the helicopter flying over a built-up residential area, the pilot executed a forced landing on Marjoram Avenue in Sinoville. The main rotor struck treetops and branches before hitting a streetlight pole. The helicopter impacted the ground hard on its right skid, which broke off, and then skidded about 20 metres before rolling onto its left side.
Injuries and Damage
The DFE and the pilot under test sustained minor injuries; the AO sustained serious injuries and was hospitalised for several days due to back injuries. The helicopter was destroyed.
Probable Cause
The investigation determined that it is likely that following the instructor's abrupt takeover of controls, he may have rolled the throttle the wrong way or pulled more collective pitch than power available during the go-around. This resulted in a rotor RPM drop, increased blade pitch and drag, and insufficient power to maintain RPM and lift, leading to the descent and forced landing.