The pilot of a police helicopter which ran out of fuel, crashing into a busy pub in Glasgow city centre and killing 10 people, did not follow emergency landing procedures despite acknowledging an audible low fuel warning five times. The final conclusions of an air accident investigation into the Clutha tragedy state that pilot David Traill failed to land within the specified 10-minute period after “continuous activation of the low fuel warnings”, but offer no explanation as to why this happened. The report of the Air Accidents Investigation Branch (AAIB) found no evidence of technical malfunction or fire. It also states that the helicopter did have enough fuel on board to complete its journey, but that 73kg of usable fuel in the main tank became unusable as a result of the fuel transfer pumps being switched off, again “for unknown reasons”. The pumps could have been switched back manually by the pilot.