What happened
On 23 February 2007, a Rotorway 162F helicopter, registration ZU-EJY, was engaged in game herding activities on a private farm near Mariental, Namibia. During the operation, the pilot attempted to transition into a hover at roughly 30 feet above ground level, positioned into the wind. As the pilot increased the collective pitch and applied right rudder to manage decreasing airspeed, the aircraft began to yaw toward the left.
Despite the pilot applying full right rudder, the leftward yaw rate accelerated rapidly. In an attempt to regain control and build forward airspeed, the pilot pushed the nose down; however, the light wind conditions meant there was insufficient weathercock effect to stabilize the aircraft. Unable to maintain flight, the pilot leveled the aircraft and allowed it to descend, resulting in the helicopter striking a thorn bush and rolling onto its right side. Following the impact, fuel spilled from the aircraft, leading to a fire that completely destroyed the helicopter. The pilot escaped the cockpit with minor injuries.
The investigation
Investigators examined the sequence of events leading to the loss of control and the subsequent fire. The investigation established that the aircraft was relatively new, having flown approximately 25 hours since its initial proving flight in November 2006. The meteorological conditions at the time of the accident were clear, with a temperature of 28°C and a light wind of 6 knots from the north.
Findings
- The primary cause of the accident was an uncontrollable leftward yaw that occurred as the pilot attempted to enter a hover.
- The light wind component prevented the weathercock effect from assisting in the directional stabilization of the aircraft.
- The aircraft's nose-down attitude failed to generate the necessary forward speed to recover from the yaw.
- Post-impact fire, fueled by leaking fuel, resulted in the total destruction of the Rotorway 162F.