Eurocopter EC120B N514AL

The pilot reported that prior to bringing the helicopter to a hover, he ran the engine to 100 percent, brought the helicopter to a hover, and proceeded to hover to the center of the helideck for a pre-takeoff check. All systems and controls were found to be operating normally. The pilot took off on a southeast heading and established a climb at a rate of 500 feet per minute. Somewhere between 300 and 400 feet, the pilot initiated a left turn to a northerly heading. At that time the pilot experienced an uncommanded cyclic movement to the right-forward quadrant and the collective started to come up (increase). The pilot added that the nose of the helicopter pitched-up and the helicopter started to roll to the left. The pilot stated that he concluded that he had experienced "a hydraulic failure of some kind," so as per the emergency procedures, he turned the hydraulic control switch on the collective lever to the "off" position. The pilot added that the hydraulic light on the console was activated indicating that the hydraulics were "off." The action taken by the pilot were not effective and the pilot was not able to regain control of the helicopter. The helicopter continued rolling to the left and entered a spin to the left while the helicopter remained in a nose low attitude. The pilot stated that the helicopter spun for about 3 to 5 revolutions and impacted the water between a 70 and a 90 degree nose down attitude. The pilot recalled that about the second spin, he initiated a "mayday" call. The pilot added that the helicopter impacted the water hard. After impacting the water, the helicopter rolled inverted, but continued to float. Prior to exiting, the pilot reported that he discharged the helicopter's float inflation bottle. The 3 main rotor servos, part number SC 5091-1 (serial numbers 877, 1393, and 533) and the Hydraulic Power Pack were examined at the Goodrich-SAMM facilities in France, under the control and supervision of the BEA. All 3 servocontrols were found to be in good conditions and performed within limits. The Hydraulic Power Pack was found to have extensive impact damage and the hydraulic pump had separated from the power back, and was missing. The actuators and the hydraulic system showed no anomalies and performed within the limits for the manufacturers' specification. The investigation concluded that the control system was installed and properly connected prior to the helicopter impact with the water. No defects or anomalies were found during the examinations that could have prevented normal operation. Additionally, all of the rotating components for the drive-train of the helicopter (main rotor blades, the rotor hub, the swatchplate, the scissors drive, the free wheel, the main gear box (transmission),etc.,) underwent a detailed examination at the manufacturer's facility in Marignane, France, under the supervision of the BEA. The examination concluded that all of the observed damage and fractures were due to overload. The investigation was inconclusive and was unable to find any pre-existing defects. The investigation concluded that the control system was properly installed and connected prior to the helicopter impact with the water. No defects or anomalies were found during the examinations that could have prevented normal operation. The reason for the loss of control could not be determined.

Quoted verbatim from the NTSB record.