Rotorcraft Report: Report Sticks With Jammed Actuator Theory in S-76 Crash

By Staff Writer | September 1, 2007
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Estonian investigators believe a Sikorsky Aircraft S-76 crashed in 2005 because one of its main-rotor blade actuators became clogged with contamination.

The Aug. 10, 2005 crash in the Gulf of Finland, near Estonia’s capital of Tallinn, killed all 12 passengers and two crewmembers on the Copterline helicopter. Investigators last month reiterated previous findings that loosened plasma coating jammed the S-76’s forward main-rotor blade actuator, rendering the aircraft uncontrollable. On the S-76C, three hydraulic actuators (forward, aft, and lateral) control the main rotor blades. Each features a side-by-side dual design in which two independent hydraulic systems power each side of an actuator.


In a related development, newspapers in the region reported that Sikorsky had paid damages to the next of kin of passengers killed in the crash. The Finnish newspaper Helsingin Sanomat said neither the company nor the relatives would discuss the payments, citing terms of their agreement.

Copterline and the families of the crew are seeking tens of millions of euros in damages in U.S. federal court in New York, alleging the helicopter crashed because of a faulty steering servo.

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