Rotor failure to blame for helicopter crash

  • 2006-08-16
  • From wire reports
TALLINN - Investigators are now certain that a rotor servo malfunction was the cause of last year's tragic helicopter crash in the Bay of Tallinn. Twelve passengers and two crew were killed when the Copterline flight to Helsinki crashed into the bay shortly after take-off on Aug. 10, 2005.

The crash has since been the subject of a commission inquiry. The vice chairman of the commission, Tonu Ader, met with representatives of the helicopter's manufacturer, Sikorsky, in the United States last week to learn of the investigation's conclusions.

He said the company agreed that a servo malfunction was the problem, although it did not accept responsibility for the accident.
"Although representatives of the helicopter's manufacturer do not directly agree with this, the in-depth investigation into the causes of the crash leaves no room for doubt as regards to why the helicopter came down," Ader said. "The helicopter was brought down by a malfunction in the main rotor servo, which resulted from the fact that parts of the plasma-sprayed coating, which is made from a mix of copper and aluminium, had broken off from the piston crown."
Sikorsky had admitted that earlier claims about a waterspout on the Bay of Tallinn were wrong, he mentioned.

Ader added that the Sikorsky plant had still not answered the commission's request for adequate tests.
"The Sikorsky company had conducted tests on the main rotor servo, but just like we thought, they haven't taken into account our requirements, and the results of the tests didn't meet our expectations," Ader said.
Following the vice chariman's visit to the United States, the Sikorsky plant agreed to conduct additional tests in line with the investigating commission's demands.

The outcome of those tests is due to be received in October, after which the final report can be completed.