Lawyers representing some of the victims of the Clutha helicopter crash have called for a public inquiry into the safety of all commercial flights in the UK.
Ten people died and more than 30 were taken to hospital after a police helicopter crashed through the roof of the packed Clutha pub in Glasgow on November 29.
Legal firm Irwin Mitchell has written to transport ministers at Westminster and Holyrood calling for a public inquiry into helicopter safety.
It comes after helicopter operators Bond started making interim payments to the victims of the crash.
It has not yet been established why the helicopter fell from the sky, although investigators said initial evidence rules out engine or gearbox failure.
The House of Commons Transport Select Committee set up an inquiry into the safety of offshore flights in the wake of last year's fatal Super Puma crash off Shetland which claimed the lives of four people.
MPs on the committee questioned representatives from helicopter operators, manufacturers, trade unions and industry bodies in Aberdeen earlier this week.
Irwin Mitchell said the investigation should be extended as there have been 20 helicopter accidents in UK airspace, with at least 40 fatalities, since 2009.
Clive Garner, head of Irwin Mitchell's aviation law team, said: "The tragedy in Glasgow has put a spotlight on the issue of helicopter safety, but the unfortunate truth is that it is just the latest in a string of tragedies and urgent action is now needed to ensure that helicopter safety standards are reviewed and improvements made where necessary.
"Our clients rightly want answers and reassurances that no-one else will have to go through the ordeals that they have been through.
"Because of our concerns, we have written to transport ministers in both the UK and Scottish parliaments demanding that they do what is right in these circumstances and launch a full public inquiry into the safety of helicopters operating within UK airspace with the aim of improving helicopter safety.
"While the review into the safety of offshore helicopter operations is certainly necessary, there are wider and more fundamental issues which need to be investigated."
The firm is asking for an investigation into the UK's helicopter safety record compared to other countries, the effectiveness of current regulation and what legislation could be used to address concerns.
Irwin Mitchell is also calling for all commercial helicopters in the UK to be installed with a black box. Helicopters weighing less than 3,175kg are currently exempt from carrying recording equipment.
Mr Garner said: "In the Clutha Vaults tragedy, we have a sophisticated twin engine helicopter that crashed in a city but there is no black box evidence to assist the investigators and quickly identify the cause of this astonishing accident.
"In our letter to the transport ministers, we have suggested that the exemption weight limits be significantly reduced to ensure more aircraft are fitted with this equipment, which would provide vital information at the early stages of an air accident investigation."
The three crew on the police helicopter who were killed were pilot David Traill, 51, Pc Tony Collins, 43, and Pc Kirsty Nelis, 36.
Those killed in the pub were John McGarrigle, 57, Mark O'Prey, 44, Gary Arthur, 48, Colin Gibson, 33, Robert Jenkins, 61, and Samuel McGhee, 56.
Customer Joe Cusker, 59, was pulled from the wreckage alive but died in hospital from his injuries almost two weeks later.