Flight MH17 which was brought down by a Russian-made missile killing 298 people was one of 160 passenger planes flying over eastern Ukraine that day, Dutch investigators have said.
The warhead exploded to the left of the cockpit, causing it to break off as it was showered with fragments of metal, and the Boeing 777 broke up in mid-air, the Dutch Safety Board found.
Relatives were told at a briefing in The Hague that loved-ones would have died very soon after the Buk missile exploded.
There were 10 Britons on board the Malaysia Airlines flight from Amsterdam to Kuala Lumpur last July.
Outlining the report findings, DSB chairman Tjibbe Joustra said civil aviation needed to learn lessons about flying over areas where armed conflict was taking place.
On that day 160 planes had flown over eastern Ukraine and three other commercial airliners were in the same area when MH17 was hit, he said.
“Every single one of those operators thought that was safe,” he said.
Operators had been told that air space above 32,000ft was open, despite a number of military planes being brought down in recent days.
The report recommended that countries where armed conflict was taking place should do more to ensure air safety and carriers should be more transparent about the routes they use.
The surface-to-air missile exploded less than one metre outside the cockpit, killing the three pilots.
Debris was scattered over a 50km area on the ground where fighting between rebel separatists and government troops was going on.
Experts reconstructed the sections of the front of the plane at the Gilze-Rijen air base in the Netherlands.
An animation showed the route the doomed plane took, how it changed course to avoid a thunderstorm, then demonstrated how the front section sheared away after impact.
The tail probably fell to the ground first, with the central section flipping over and catching fire on impact.
The inquiry team indicated the missile was fired from a 320km square area. Russian experts said it was a smaller area, and Ukrainians indicated a smaller area still.
The DSB did not set out to find who fired the missile. That will be dealt with by prosecutors later.
Russian missile-makers have carried out their own investigation which they say point to Ukrainian fighters being to blame.
After the findings were released, Prime Minister David Cameron, said: “We have always been clear that justice must be done for all of the victims of MH17 and today’s report brings us one step closer to establishing the truth.
“We, alongside our partners, will continue to send a clear message; those responsible for downing this plane will be held to account.”
Barry Sweeney, whose son Liam, 28, was on board, said he had been told that the passengers would have died soon after impact.
He told the BBC: “That is a comfort for 298 sets of relatives.”
They wanted to know their loved ones had not suffered. “We cannot be 100%, but we have to think that was the case,” he said.
He added: “I’m going to have to go away and think ‘Yes, Liam died instantly as (did) 297 other people’. If you think otherwise, it’s just going to hurt forever.”
Liam was travelling with his friend and fellow Newcastle United superfan John Alder to watch their side play pre-season games in New Zealand.
Mr Sweeney believed his son was “probably having a drink” as the plane flew high over Ukraine, and would have been excited.
“It was the trip of a lifetime, unfortunately they didn’t get there,” Mr Sweeney said.
The investigation was led by Holland because 196 of the victims were Dutch.
The MH17 disaster followed on from the disappearance in March last year of Malaysia Airlines flight MH370, which was flying from Kuala Lumpur to Beijing with 237 passengers on board.
Claudio Villaca-Vanetta, whose husband Glenn Thomas, from Blackpool, died on board MH17, told BBC Radio 4’s World at One: “We had some of the answers we were looking for today, but by far not all of them.
“We now know for sure that Malaysia Airlines was allowed to fly there, and we know now that it was a bad decision by Ukraine to leave the airspace open and that by just raising the cruise height it was safe for commercial airliners. We know there was a missile which is manufactured in Russia only.
“Of course, this doesn’t tell us who did it, who is accountable for it. That is where we want to get now.”
Mr Villaca-Vanetta said victims’ families had been told their loved ones would have died instantly or very quickly. But he added: “Even if it was the estimated nine seconds for somebody to lose consciousness, it is still a lot of time. For most families of victims, including myself, we went through counselling and this was maybe the hardest point to accept - the cruelty and the violence on bodies.”