The first half of the Clutha inquiry closed last week, with more evidence from various engineering staff at Bond Helicopters, confirming that the company had struggled with numerous fuel tank sensor problems over a period of years. Mr Jim Remfry, head of maintenance at Babcock – now the owners of Bond – confirmed that he was aware of several instances of Airbus EC135 pilots reporting apparently faulty fuel readings.
One complaint came on 30 September 2013, just two months before the fatal crash that killed all three occupants of the Police Scotland helicopter and seven Clutha customers below. Pilot Craig Trott raised the issue by email with maintenance staff in Glasgow. The helicopter had been fuelled at 400kg before take-off but after a couple of hours the display was showing 310kg. On starting the engine, it showed 295kg then on take off it was 320kg before going to a 'normal burn rate'. There was no sign of fuel leakage.
The pilot was told that two new fuel sensors would be sent to the city heliport from Bond headquarters at Staverton, Gloucestershire. There is no record that the sensors were fitted, although Mr Remfry told the inquiry that the incident was a 'discrepancy' rather than a hard fault. He could only surmise that the sensors were kept on standby. He said the team was constantly looking at parts that were used more than others and doing anything that can be done to make those parts more reliable.
'I was aware there was reliability issues with a number of components. We became aware to some degree that there are reliability issues with various systems. This was one of many systems that could have been more reliable,' added Mr Remfry. 'We had a number of reports from the log where pilots would, on fuelling up the aircraft, report that the amount of fuel gone in the aircraft against the amount of fuel on the display would show a discrepancy.'
His evidence was among that of several witnesses to indicate regular problems with 'over-readings', where sensors reported that either the main tank or supply tanks in the company's EC135 fleet contained more fuel than they actually had. Although allowances are always made – because fuel levels can change according to the attitude of the helicopter, which may be climbing or banking – the discrepancies were greater than normal.
The sensors were also sensitive to water contamination, either if the aircraft were refuelled during heavy rain, or if water seeped in to the system during the regular washing regime for the EC135. Bond changed regimes to try and minimise contamination. The inquiry also heard earlier that an ad-hoc alteration was made to part of the system by Bond when problems were first recorded by its engineers in 2003, but that these took 11 years to be approved formally by manufacturers Airbus.
Earlier, the inquiry was shown an information notice, dated 21 January 2013, from Eurocopter (Airbus) about the risks of water contamination to the fuel system. It stated that a 'couple of drops of water' concentrated between the metal tubes of the fuel level sensor could be enough to affect the signal to the display shown to the pilot.
The Fatal Accident Inquiry (FAI) may finish earlier than expected, if the Crown and other legal parties can reach agreements about certain evidence. The FAI has taken a planned six-week break from Monday, because the facilities at Hampden stadium are required for several events including this weekend's Scottish Cup final, two men's and women's football international matches, and a concert by the American performer Pink. Hampden was chosen as the inquiry venue because its facilities could cope with the numbers of people attending – in some days approaching 50, plus the public and press.
The inquiry is due to hear evidence from pilots and engineers during the first two weeks of July. However, Sheriff Principal Craig Turnbull indicated that he may be ready to receive summations from the various parties by mid-July. Fourteen legal teams are attending the FAI, representing the families of some victims, as well as interested parties including Babcock, Airbus, Police Scotland, the engine manufacturers Safran and the Civil Aviation Authority. Crown evidence has been led by Sean Smith QC.
The Crown is expected to update the sheriff principal when the inquiry resumes on 1 July. Captain David Traill, 51, and police observers Tony Collins, 43, and Kirsty Nelis, 36, died in the cockpit, when G-SPAO lost control and crashed into the roof of the Clutha, killing customers Gary Arthur, 48; Joe Cusker, 59; Colin Gibson, 33; Robert Jenkins, 61; John McGarrigle, 57; Samuel McGhee, 56; and Mark O'Prey, 44. Thirty-one others were injured.
Maurice Smith will report again on the Clutha FAI in SR on Wednesday 7 August