A damaged tail piston was the cause of a helicopter accident on a North Sea oil rig.
The accident has led to the grounding of all Sikorsky S92 model helicopters following the investigation.
Accident happened during landing
The helicopter was attempting to land on the West Franklin platform on December 28 at the time of the incident.
During the manoeuvre, the vehicle pitched to the side and left significant gouge marks on the deck, the Air Accidents Investigation Branch (AAIB) has said.
At the time, there were nine passengers and two crew on board the helicopter. Fortunately, no-one was injured during the accident.
All Sikorsky S92 helicopters have since been grounded to undergo maintenance and inspection work following the accident.
Not the first time
The accident report found that the helicopter “yawed rapidly to the right, reaching a maximum rate of 30 degrees per second” when it was four feet above the landing platform. This led to the landing gear striking the deck.
It was also revealed that the same helicopter had “yawed unexpectedly to the right through 45 degrees” on an earlier departure. But this incident was put down to turbulence at the time.
The AAIB says “it was immediately apparent that the tail rotor servo piston was damaged” when inspectors removed helicopter panels.
There were also signs of “severe overheating” and “extreme wear” on bearings.
Date Published: January 27, 2017
Author: Jonathan Brown