The operators of a helicopter which crashed into the Clutha were increasingly concerned about problems with fuel indicators before the crash, an inquiry has heard.
Pilot David Traill, two other crew members and seven bar customers died when the police helicopter crashed in Glasgow on November 29, 2013.
The helicopter manufacturer issued an information notice dated January 21, 2013 regarding water contamination of the fuel system, which stated that a “couple of drops of water” concentrated between the metal tubes of the fuel level sensor may be enough to affect the display shown to the pilot.
Martin Forster, avionics manager at Babcock (formerly Bond) which operated the helicopter, said the company repeatedly experienced problems with fuel probes and had to send them back to Airbus for replacements.
The inquiry has heard that the aircraft which crashed, an EC 135, experienced problems with fuel readings in the months before the crash.
David Adams, representing the partner of pilot David Traill, asked: “Prior to the crash in November 2013 were fuel indicator issues in EC135s a regular occurrence in your experience?”
Mr Forster replied: “Semi-regular. The fuel probe replacements and problems with the fuel system were within the areas of the aircraft that we were concerned about.
“It is a big fleet, we do get failures on a regular basis, we’ve got lots of different systems but this had become more prominent and was creeping up our list of areas that needed further investigation.”
Asked whether he was aware of it as a problem when he started at Bond as an avionics engineer in 2008, he said: “No not really, it seemed to be a shift into 2013 from late 2012. It seemed to be a more common occurrence.
“I was thinking about whether Airbus had changed supplier that was putting us in a position where the parts were not as reliable as we would have expected them to be and we were seeing more faults than previously.”
The inquiry was shown technical logs which noted that on July 8, 2013 the fuel content indication in the aircraft which later crashed into the Clutha was found to be inaccurate and work was carried out to fix the problem.
The log showed another problem in October that year when engineers defuelling the tank found that the quantity indicator was stuck at 11kg when the tank was empty and again work was carried out to resolve the issue.
More than 100 people were at the Clutha Vaults pub when the helicopter, returning to its base on the banks of the River Clyde, crashed through the roof.
Pub customers John McGarrigle, Mark O’Prey, Gary Arthur, Colin Gibson, Robert Jenkins, Samuel McGhee and Joe Cusker died, while pilot David Traill and crew Pc Tony Collins and Pc Kirsty Nelis were also killed.
The inquiry before Sheriff Principal Craig Turnbull continues at the temporary court at Hampden Park on Thursday.