One described the aircraft as sounding “like an old car trying to start - but a 1000 times louder” seconds before it plunged on to the roof of the Clutha Bar in Bridgegate, close to the River Clyde, on November 29, 2013.
The eyewitnesses, all members of the public, were giving evidence on the opening day of the fatal accident inquiry (FAI) into the disaster.
Seven were killed inside the Clutha Bar as well as the three on board the helicopter, which was operated by Bond Air Services on behalf of Police Scotland.
A minute’s silence was held at the start of the inquiry on Monday morning in memory of those who died.
The FAI before Sheriff Principal Craig Turnbull is taking place in a temporary court at Hampden Park.
Ernest Docherty, 64, told the inquiry he had finished work on the night in question and was walking to collect his car in the Gorbals before driving home.
As he crossed the King Street car park he became aware of the helicopter overhead, which he described as sounding like “an old car trying to start - but 1000 times louder”.
He added: “My initial thought at the time was that it was going to come down behind The Clutha.”
Pub customers Mark O’Prey, Gary Arthur, John McGarrigle, Colin Gibson, Robert Jenkins, Samuel McGhee and Joe Cusker died, while pilot David Traill and crew Tony Collins and Kirsty Nelis were also killed in the crash.
Personal statements about some of those who died were read out in tribute to them.
Kerry McGhee described her father Samuel McGhee as a hard worker who was “very sociable” with “many friends”.
A statement from Colin Gibson’s family said: “If you were lucky enough to meet him, you knew you had as he left a lasting impression on you.
“Ever since he was a young boy he enjoyed helping people.
“He had never visited the Clutha bar before. Colin just happened to be in the wrong place at the wrong time.”
The sisters of Gary Arthur told the inquiry in a statement: “Nothing will ever bring our brother back but hopefully we will finally be given the chance to find closure.
“We want to remember Gary as a much-loved person and not just a victim of the Clutha.”
The first person to give evidence was witness Andrew Bergin.
The 30-year-old solicitor from Airdrie, North Lanarkshire, told how he was walking by the riverside on the night in question.
He said of the helicopter: “It made what I can only describe as a spluttering noise. It wasn’t any lower than I would have seen it before.
“The tail of the helicopter dipped and pointed to the ground. Simultaneously, the light on the helicopter went out.
“It seemed to me that the rotor stopped spinning. It was still turning but not under power.
“It seemed to immediately lose height as soon as the spluttering occurred.
“Everything happened more or less at the same time.”
The purpose of the FAI is to determine the cause of the deaths, establish whether they could have been prevented and enable the sheriff to make recommendations that could prevent fatalities in similar circumstances.
More than 100 people were at the Clutha Vaults pub when the helicopter, returning to its base on the banks of the River Clyde, crashed through the roof.
An Air Accidents Investigations Branch (AAIB) report published in 2015 found two fuel supply switches were off and the pilot did not follow emergency procedures after a fuel warning in the cockpit.
The Crown Office has previously said there is insufficient evidence for criminal proceedings.
A total of 57 Crown witnesses are expected to give evidence at the inquiry, down from a previous estimate of 85.
Police have taken more than 2,000 statements as part of preparations for the FAI, while the Crown has around 1,400 productions.
The inquiry is expected to involve around three months of evidence spread over six calendar months this year.