What happened
On August 1, 2024, a private flight departed from Warsaw-Modlin (EPMO) bound for Niedźwiedzi Róg in a Robinson R44 Cadet, registration SP-NHM. During the climb to 1,500 ft AMSL, the pilot observed a decrease in vertical climb speed and fluctuations in the charge pressure gauge. As the aircraft reached approximately 1,200 ft AMSL, the pressure fluctuations increased to +/- 2.5 inHg, accompanied by a noticeable drop in engine power.
In response to the perceived power loss, the pilot decided to perform an emergency landing via autorotation at an altitude of approximately 900 ft AMSL. During the descent, the pilot reduced forward speed, which increased the rate of descent. Shortly before impact, the pilot performed a flare maneuver at approximately 13 ft above the ground. The helicopter touched down at a high forward speed of approximately 35 kts. The impact caused the aircraft to bounce and strike the ground, resulting in the destruction of the aircraft. The pilot sustained minor injuries and was able to exit the wreckage unassisted.
The investigation
The PKBWL investigation examined the technical condition of the Robinson R44 Cadet, the meteorological conditions, and the pilot's decision-making process. Investigators analyzed flight data from SkyDemon to reconstruct the final phase of the flight. The investigation focused on the cause of the engine performance degradation and the execution of the emergency procedures. While the investigation could not determine the specific cause of the charge pressure fluctuations or the degraded engine performance, it established that the engine was still producing power and the aircraft was not in a state of total power loss.
Findings
- The pilot was properly licensed and not under the influence of alcohol.
- The aircraft was certified, and the weight and center of gravity were within regulatory limits.
- The fuel was of the correct class and uncontaminated.
- The pilot made an unjustified decision to perform an emergency landing (autorotation) instead of a precautionary landing while the engine was still running.
- The emergency landing was improperly executed because the pilot failed to reduce engine power by turning the throttle to the stop, which allowed the engine to increase power during the flare and touchdown, leading to a loss of control.