Investigators from the National Transportation Safety Board have found two possible problems with the hydraulic system of the AS 350 Heli USA helicopter that crashed March 8 at Princeville, Kauai, killing four people.
In the preliminary report released today on the NTSB Web site, investigators said they found that the hydraulic sight glass was broken and seeping. The sight glass allows the pilot or mechanics to look into the hydraulic fluid tank. The report did not say whether it was broken before or after impact. But it did say that the hydraulic reservoir was full at the time of examination.

They also found that one of the servos was still attached to the transmission, but not to the rest of the hydraulic system. Servos are the portions of the hydraulic system that boosts the pilot’s controls, using the power generated by the hydraulic pump, to the controls of the rotor mechanisms, making a helicopter easier to turn and stay in the air.

The left lateral servo was not connected to the hydraulic system but not damaged by the crash, the report indicated. The threads of the servo and on the transmission were not stripped, and the parts were able to rotate properly, the report continued.

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(Source: Honolulu Star-Bulletin)