THERE was no evidence of fuel contamination or of a fuel leak in the helicopter that crashed into the Clutha Vaults Bar, an inquiry was told.

A Fatal Accident Inquiry heard evidence from senior inspector of air accidents Robert Vickery, who travelled through the night to be at the scene at 9am the day following the crash.

Mr Vickery, of the Air Accident Investigation Branch (AAIB), was questioned on day five of the inquiry about issues regarding fuel sensors in the aircraft.

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He travelled from England with a team of investigators and, following a briefing at Govan Police Station, arrived on site on November 30, 2013.

Mr Vickery told the court that fuel was extracted from the helicopter for analysis while it was still suspended above the Clutha.

He went on to explain fuel readings onboard could be affected by water or compressor washing fluid in the fuel tank, which could enter the tank during pressure washing.

The aircraft, G-SPAO, had been pressure washed on two dates close to the crash, November 2 and November 17/18.

Under cross-examination by Donald Findlay QC, for the family of victim Robert Jenkins, Mr Vickery said there was "no evidence" of fuel contamination.

Read more: Lack of Clutha crash data 'frustrating'

Donald Findlay QC, representing the family of victim Robert Jenkins, questioned Mr Vickery about the fuel tank sensors.

If contaminated, the court heard, they could give an over-reading, suggesting there was more fuel on board than contained in the tanks.

Mr Findlay asked whether an over-reading on the supply tank could be "significant or insignificant" and Mr Vickery agreed it could be either.

He added: "Could you say it was a teaspoon, a cup, a half pint or are you going to simply say you don't know?"

Mr Vickery said it would not be possible to tell.

Mr Findlay said: "Did you see any evidence that fuel contamination of any kind had any part to play in the demise of this aircraft?"

Mr Vickery replied: "No."

Mr Findlay added: "Would you have expected to find any evidence to back that up or is this just another element we don't know about?"

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Mr Vickery explained the rate of fuel throughput is fast for a small helicopter and added in a: “dynamic machine and rate of consumption you would expect to see a little but barely detectable”.

Mr Findlay suggested to Mr Vickery that "absence of evidence is not evidence of absence" and asked if he used "inference" or "speculation" in his work.

He said: "You don't infer and you certainly don't speculate?"

Mr Vickery replied: "We use facts."

The court was shown photographs of the inside of the helicopter's fuel tanks, taken after it was removed from the Clutha and transported to the AAIB's base in Farnborough.

Mr Vickery confirmed the helicopter was kept at the same angle it had come to rest while it was being moved.

The helicopter, being flown by pilot David Traill and with PCs Tony Collins and Kirsty Nelis on board, was called out on an operation in Oatlands on the night of the crash.

It then flew to Midlothian, Bothwell, Uddingston and Bargeddie before crashing into the roof of the Clutha Vaults as it returned to Glasgow City Heliport.

The inquiry heard Captain Traill would have heard five low fuel warnings towards the end of the final flight.

However, there was no flight recorder and so there is no evidence when they came on or for how long.

Clutha customers Gary Arthur, 48; Joe Cusker, 59; Colin Gibson, 33; Robert Jenkins, 61; John McGarrigle, 58; Samuel McGhee, 56; and Mark O'Prey, 44 were all killed while a further 31 people were injured.

The inquiry, before Sheriff Principal Craig Turnbull, continues at Hampden Park.