NO MAYDAY call was made from the police helicopter before it crashed on to the roof of The Clutha, killing at least nine people and injuring many more.
Detailed examinations will now be carried out in Farnborough and aviation experts believe there should be some answers within days.
A formal inquiry into the crash by the Air Accidents Investigation Branch (AAIB) is likely to take several months.
Yesterday, the emergency services managed to remove the wreckage of the helicopter from the pub, allowing investigators access to what lay underneath for the first time. Removing the helicopter aided Police Scotland’s “painstaking” search as they sought to ensure all the victims were recovered.
Deputy Chief Inspector Dave Miller of the AAIB said nothing had fallen from the aircraft and there was nothing to link the incident with helicopter crashes in the North Sea.
Eurocopter has not grounded its fleet of more than 1,000 EC135s worldwide. But it is unclear whether this means they do not believe there is a technical fault, which could affect other models. Human error or a catastrophic event beyond the pilot’s control have also been raised by aviation experts as possible explanations.
Last night, the AAIB would not be drawn on possible causes of the crash.
Speaking at the crash site in Glasgow yesterday, Mr Miller said: “The AAIB were notified of this accident late on Friday night. We dispatched a team of investigators.
“The team arrived here at approximately 9:15am on Saturday. The recovery operation has been hazardous and challenging.”
He confirmed that the helicopter did not have a black box, but did have instruments that could record data.
“I can confirm that nothing detached from the helicopter in flight before the accident and four rotor blades were attached after the impact,” he said.
“There is no cause to connect this accident to previous accidents involving helicopters operating in the North Sea.
“The wreckage is now being recovered and will be taken under police escort to the AAIB facilities in Farnborough where a detailed examination will commence.
“If anything of immediate concern comes to light we will make that known without delay. We will be publishing a report very soon.”
Shortly after he spoke, the Eurocoptor was fastened onto the back of a lorry, covered with tarpaulin and driven away, at about 3:20pm.
Deputy Chief Constable Rose Fitzpatrick, of Police Scotland, said: “This now enables us, working with Scottish Fire and Rescue Service, to continue the search and recovery operation, to satisfy ourselves that all the victims of Friday night’s tragic incident have been recovered.
“This continues to be a difficult and complex operation. A painstaking process is under way to search and also to preserve the scene which is, of course, subject to investigation.
“The uncertainty for the families of those who have died is at the front of our minds. It remains our absolute priority to give clarity to those affected as soon as we are able.”
Police Scotland, manufacturer Eurocopter and Bond Aviation Group, which operates the helicopter, including supplying the pilot, all said it was too early to reach any conclusions about the cause of the crash.
However, Eurocopter has said EC135s should continue to fly. It issued a safety information notice saying: “At this stage, Eurocopter is not in a position to recommend any special measures to our EC135 operators.
“As soon as we obtain more substantial information we will immediately inform all of our EC135 customers.”
Asked what that indicated, Charles Newport, consultant for Aviation Network Associates, said: “Quite possibly it could be pilot error, that’s the only other factor I can think of.
“The aircraft could have been flying too low and the pilot could have become disorientated. He could have been blinded by a laser. To me, it seems to be a catastrophe of some sort, unless the pilot had a heart attack.
“Until they look at the body and carry out pathology tests, and look at the aircraft, there’s little you can do apart from speculate.”
Mr Newport backed Eurocopter’s decision not to ground the rest of the fleet. “Unless they can identify what the problem is, there’s no reason to ground the helicopters,” he said.
Mr Miller described the recovery operation as “hazardous and very, very challenging”.
He said: “The AAIB need to record and preserve the evidence, but we are very mindful of the sensitivities that have surrounded the recovery of the bodies of those who have been fatally injured.
“While waiting for the wreckage to be recovered we have been looking at other aspects.
“We have the recorded radar data, so we know the track of the helicopter [and] the height and speed of the helicopter in the latter stages of its flight.”
He said it may be possible to download engine data from microchips on the helicopter.
Police Scotland has said the helicopter was tested on the advice of its operator Bond Air Services last July after Scotland’s two air ambulance helicopters were suspended following a warning about their safety.