The Air Accidents Investigation Branch (AAIB) report into the Clutha tragedy raises a number of questions for victims' families and they "deserve answers", Scotland's prosecution service said.
The Crown Office said it welcomed the publication of the report into the 2013 police helicopter crash in Glasgow in which 10 people died,
The report recommended recommended that aviation regulator the Civil Aviation Authority should require all police helicopters to be fitted with equipment to record data, audio and images.
As no black box was required on the helicopter, the cause cannot be fully established.
Further investigations into the issues raised by the report will now be carried out, the Crown Office said.
The report raises a number of questions for which the families of the victims deserve answers. The Crown will now conduct further investigations into some of the complex issues raised by the AAIB report. We will endeavour to do this as quickly as possible but these matters are challenging and the necessary expertise is restricted to a small number of specialists. We will continue to keep the families advised of progress with the investigation.
The prosecution service said it will also hold a Fatal Accident Inquiry, which is mandatory when deaths occur in the course of employment.
Experienced helicopter pilot David Traill, of Police Scotland's air support unit, and nine others died when the helicopter fell from the sky and crashed through the roof of the busy bar.
An interim report showed that the helicopter had suffered double engine failure due to fuel being unable to reach the engines but the AAIB has not been able to conclude why it happened.
The two fuel supply switches were in the off position, ultimately leading to both engines cutting out, the report said.
It also concluded that the helicopter did not land within the recommended 10-minute period after the activation of low fuel warnings for "unknown reasons".
But the AAIB said it does not blame any individual for the crash.
Speaking after a family briefing on Wednesday, John McGarrigle, whose father John died in the tragedy, said: "Flight data recorders should be installed in every passenger-carrying aircraft - simple as. If we had that, we would know a lot more. It's just question upon question upon question."
I'm furious. I came here very optimistic, very hopeful, knowing that the AAIB are very impartial but I just feel really let down by those guys because these are the people that we came here tonight to get answers off of and we never got any answers.
Anne-Marie Kennedy, who was working behind the bar and was trapped in the wreckage, said: "It's shown me that they should have black boxes for defo, it's shown me the need for other regulation, but other than that nothing."
Our thoughts are with the families of the victims of this tragic accident. The AAIB is independent, tasked with investigating the causes of accidents to prevent recurrence and help make aviation safer.
Police Scotland Deputy Chief Constable Iain Livingstone said: "The crash had a profound effect on our communities and the desire for answers to what happened and why is entirely understandable.
"Since the crash, Police Scotland has been carrying out an extensive major investigation under the direction of the Crown Office and Procurator Fiscal Service."
Our thoughts are with the families and friends of those who lost their lives, and those who were touched by the tragic accident at the Clutha Bar. Today's AAIB report is an important step in the process of understanding the terrible events of that night, although some questions remain unanswered.