What happened
On 2 December 2016, a Robinson R44 Raven II, registration ZS-RVY, was conducting a private scenic flight near the Rooikoppies dam in the North West Province. The aircraft, operated by Brits Pallets CC, was carrying the pilot and two passengers when the crew experienced a sudden loss of power.
While performing a 180-degree left turn at approximately 500ft AGL, the pilot heard the low main rotor RPM warning. Upon checking the flight instruments, the pilot confirmed that both the engine and the main rotor RPM indicators showed a loss of power. In an attempt to recover, the pilot increased the throttle, lowered the collective, and lowered the nose to gain airspeed. Despite these efforts, the main rotor RPM continued to decay, dropping to 80%.
Faced with the power loss, the pilot attempted a forced landing into the water near the riverbed. During the flare, the tail rotor struck the water, causing the aircraft to pitch forward. The impact resulted in the windshield dislodging and the helicopter sustaining substantial damages. There were no injuries to the three occupants.
The investigation
The SACAA AIID investigation confirmed that the pilot held a valid private pilot license and a medical certificate, with approximately 208 hours of experience on the aircraft type. The helicopter held a valid certificate of airworthiness.
Investigators examined the flight profile and noted that the aircraft was engaged in site viewing. The investigation considered the manufacturer's emergency procedures for power failures, which advise lowering the collective immediately to enter autorotation. The inquiry also noted that the aircraft may have been flying below 500ft AGL to facilitate better viewing, which reduced the available altitude for recovery.
Findings
- The primary cause of the accident was an unsuccessful forced landing on an unsuitable surface (water).
- The loss of main rotor RPM was attributed to improper coordination during the flight.
- The investigation identified the use of incorrect flight techniques and possible pilot distraction during the turn as contributing factors.