20220219001009A

On 02/19/2022, approximately 18:30 pacific standard time, huntington Beach police helicopter, MD500N, N521HB, operating as a public aircraft, responded to a call near the lido peninsula in Newport Beach, CA. While performing right hand orbits over the scene at 400 to 500 feet, the pilot reported he suddenly experienced an un-commanded right yaw resulting in loss of control of the aircraft. Pilot said the engine was running good, just lost all anti torque authority, adding power slowed the right spin. Surveillance footage recovered from the helicopters camera showed the helicopter making several right hand orbits prior to an immediate right hand spin. This footage included the aircraft speed, altitude and direction, at approximately 13 knots and at 400 foot altitude the spin started, radar data shows similar data. Witnesses reported seeing the helicopter spinning out of control before impacting the water. Video surveillance from a home showed the helicopter spinning to the right in a nose down attitude before impacting the water right side first, in a nose down attitude. The observer in the right seat sustained fatal injuries. The flight was in night/vfr conditions, weather data indicated wind was variable at 3KTS to calm. Three rotor blades remained attached to the rotor head, two blades had separated and recovered in the vicinity of the impact site. The horizontal and the two vertical tail assemblies were displaced to the left, supporting bracket and control arm were broken. The rotating cone was displaced off the track. The tail boom remained attached to the fuselage. Cockpit windscreens / windows were shattered. The horizontal /vertical tail assembly was removed for transportation. The helicopter was trucked to a storage yard 4 miles away. The FAA iic, continued the field investigation at the storage yard. In addition the NTSB iic, NTSB helicopter specialist, MD helicopter representative, rolls-royce engine representative assisted. Two huntington Beach flight department mechanics were also present. The following systems were checked for movement and continuity was confirmed (although there was damaged and broken linkages on the swash plate) , collective, cyclic, throttle, anti-torque control system from the pedals all the way to the variable pitch fan, right vertical stabilizer and finally to the rotating control cone. The main rotor drive system rotated freely be hand and there was continuity between the engine, transmission, drive shafts and the notar anti-torque fan. The fan gearbox and main transmission chip detector checked clean with minor fuzz, and no metallic chips found. Fuel was found in the fuel lines, going to the spray nozzle at the burner can. All ?b? Nuts in the engine compartment were at least finger tight according to the rolls-royce representative. What appeared to be jet fuel was in the gas tank, the fuel smelled like jet fuel. The right side anti-torque pedals were not installed. The yaw stability augmentation system (ysas) actuator that controls the right vertical tail to aid in yaw stability was in the full right yaw position. The ysas actuator, gyro and computer was removed by the NTSB for further testing. The pilot completed recurrent MD520N training on September 2, 2020 and MD530F differences training on February 2, 2022. A review of the weight & balanced data obtained indicated the helicopter was within its center of gravity and maximum/minimum weight limit.