Investigators said Monday they had found no evidence that a police helicopter which crashed into a busy pub in Scotland's biggest city Glasgow last month, killing nine people, suffered a mechanical failure.
The Eurocopter EC 135 chopper crashed into the Clutha pub in Glasgow's city-centre on November 29, killing all three crew members and six people who had been watching a band play inside.
Britain's Air Accidents Investigation Branch (AAIB) said the crash remained a mystery 10 days later, with no evidence of engine or gearbox failure, and that "all significant components were present" when it smashed into the pub.
The helicopter still had 95 litres (25 gallons) of fuel left, the AAIB said. Visibility had been good and there were only light winds.
The twin-engined chopper had no flight recorders and was not required to do so, but investigators are set to examine other systems that recorded fault codes as well as image and audio recordings.
The helicopter departed from Glasgow City Heliport at 8:45 pm. Radar contact was lost at 10:22 pm, just before the crash, the AAIB said.
A witness told the agency that the helicopter had made a loud noise like a "misfiring car" before dropping rapidly out of the sky.
All 1,100 of Eurocopter's EC135 choppers - which the manufacturer has sold to nearly 300 clients - were temporarily grounded last year over safety fears after a crack appeared in the main rotor hub shaft of one of the aircraft. In total, cracks were found in five of the helicopters.
Eurocopter, which is owned by European aerospace giant EADS, has insisted it is unlikely that a crack caused the Glasgow crash.