Flights of a helicopter that crashed into the North Sea killing 16 men were temporarily halted just a week before the accident after a problem was discovered with its gearbox, an inquiry has heard.
Verner Hill, an engineer and deputy shift supervisor with Bond at the time, told a fatal accident inquiry at the Town House in Aberdeen that he was “unhappy” and “uneasy” after a problem was detected in the aircraft.
He was on duty on March 25 2009 when a colleague flagged up a problem with the helicopter’s health and usage monitoring systems during a turnaround inspection after the aircraft’s first flight rotation that day.
Mr Hill said data downloaded from the Hums showed a purple flashing warning light on the main gearbox indicator that appeared to indicate its chip detector had picked up a particle of metal.
The issue was only discovered after the helicopter had taken off on another flight at 9.25am, the inquiry heard.
He was shown a report prepared after the fatal crash which, he told the inquiry, appeared to indicate that the particle had been detected 94 times.
When the helicopter returned, Mr Hill and another colleague carried out an inspection on the main gearbox and no particles were found, the inquiry heard.
But an examination of the Hums after the helicopter’s second flight still showed the warning.
Mr Hill said he was “uneasy” with the situation.
“I wasn’t happy with what I was seeing,” he said. “I spoke to the oncoming supervisor about it. I can’t remember who decided but we took it offline.
“It was due to go on a training flight but we took it off the training flight and put it into the hangar for an after-flight inspection to be carried out.”
Meanwhile Bond’s maintenance manager Ronald Wright told the fatal accident inquiry that he had been involved in work to replace three of the four components of the gearbox between April 9-11, 2008.
Nearly a year later, on April 1, 2009, the AS332 L2 crashed off the north-east coast, with inspectors from the Air Accident Investigation Branch (AAIB) later ruling it had suffered a “catastrophic failure” of its main rotor gearbox.
Mr Wright, 48, who is a licensed engineer, said the work involved sending the parts – the main component, right accessory and epicyclic gearbox- back to helicopter manufacturer Eurocopter, who would either overhaul them or replace them with new equipment.
Mr Wright was unable to tell the inquiry at the Town House in Aberdeen if Bond had been provided with new or overhauled parts.
He added that the fourth component, the left accessory, was replaced on October 1, 2008.
See full coverage of day five of the inquiry in tomorrow’s Press and Journal