NTSB: ’Urgent’ Action Needed on Sikorsky S-76
An ongoing investigation into the August 10 fatal crash of an S-76C+ in the Baltic Sea has led the NTSB to ask the FAA to take “urgent” action on several recommendations. Flight-data recordings show that the twin-turbine helicopter “pitched up and rolled to the left, followed by a series of rotations to the right before striking the water,” killing all 14 aboard. The investigation to date revealed that one of three main-rotor blade hydraulic actuators had an “uncommanded” extension, resulting in loss of control. Subsequent investigation found a “number of serious discrepancies within the forward actuator.” The Safety Board wants the FAA to require S-76 operators to conduct immediate and recurring tests and corrections for hydraulic leakage and contamination in all of the main rotor actuators with more than 500 hours since new or overhaul. Additionally, the NTSB wants the FAA to reemphasize to S-76 operators the importance of, and requirement for, a preflight check of control movement smoothness and flight control “stick-jump” at every engine start.