What happened
On November 16, 2007, a Robinson R44, registration PT-YFR, was performing a flight from Palmas, TO, to a farm in Pedro Afonso, TO. After picking up two additional passengers at an intermediate location, the aircraft approached the destination near the headquarters of Fazenda Santa Fé.
During the landing sequence, the pilot performed a hover at approximately 30 meters from the intended landing spot. While attempting to taxi from the hover to the landing point, the aircraft began to yaw to the right. The pilot attempted to correct the attitude by pulling the collective and increasing power; however, this action caused the aircraft to pitch forward excessively and increased the rightward rotation. The helicopter struck the ground and subsequently overturned, causing the main rotor to impact the terrain.
The investigation
CENIPA investigators examined the flight sequence and the pilot's responses to the developing instability. The investigation focused on the effectiveness of the tail rotor during low-altitude taxiing and the pilot's application of power. The aircraft was found to be within weight and center of gravity limits, and all required certifications and maintenance records were up to date. The investigation also reviewed the manufacturer's manual, which specifies procedures for loss of tail rotor thrust during a hover.
Findings
- The pilot's decision to increase power during a period of reduced tail rotor effectiveness significantly aggravated the loss of control.
- The aircraft experienced a loss of control during ground taxiing due to the pilot's improper application of flight controls, specifically allowing the nose to pitch down.
- At the low altitude of the taxiing maneuver, the available left pedal authority was insufficient to counteract the yaw.
- The aircraft sustained severe damage.
- One passenger sustained minor injuries, while the pilot and the other two passengers were uninjured.