Iran is accused of orchestrating a cover-up during its year-long investigation into the shooting down of a Ukrainian Airlines flight that killed all 176 people on board. Flight PS752, bound for Kiev, was hit by two Iranian missiles within minutes of take-off from Tehran’s Iman Khomeini International Airport on January 8, 2020, a disaster the regime described as a tragic accident. As the anniversary looms, Iranian air accident investigators are yet to publish a final report despite concerted pressure from foreign governments to come clean about the circumstances that led to the downing of the civilian airliner carrying passengers from six countries. Iran says the missile was mistakenly fired by a mobile defence unit positioned on the edge of the airport. Its account includes a series of calamitous blunders by the missile unit, including misaligning the unit by 107 degrees – nearly one third of the compass – and failing to recognise the problem. It said the unit then suffered a communications failure that cut it off from its commanders. The regime finally claims that the two surface-to-air missiles were launched at PS752 in direct contravention of orders not to fire until authorised by central command. The litany of failures was dismissed by the families of the victims who said they knew from day one that it was not human error. They believe the final definitive report of the disaster has not been published by Iran because it will expose its failure to properly investigate what happened and attribute blame to those responsible. "We believe that Iran will do anything it can to hide the truth," said Amirali Alavi, a campaigner for the families and whose mother died on the aircraft. "And everybody's looking for answers." Key questions unanswered include: Up to six Iranians face charges over the shooting down of the aircraft but their identities and their positions in the military hierarchy are unknown. The Canadian report said: “Iran bears a heavy burden of responsibility to be completely comprehensive and transparent in substantiating its explanations with credible, compelling evidence, which has not yet been forthcoming.” The missile attack on the plane came amid heightened tensions after the assassination in a US drone strike five days earlier of Qassem Suleimani, the head of the Quds Force of the Islamic Revolutionary Guard Corps. The killing prompted promises of retribution with several volleys of Iranian missiles fired at two air bases in Iraq where US forces were housed just hours before the aircraft was attacked. But Iran did not close its airspace to civilian aircraft despite airlines from countries including the US, Canada and Australia avoiding the area. Lawyers for some of the families said Iran was on the highest state of defensive alert and the IRGC was “totally prepared for a fully-fledged war”. Some relatives of those killed believe the attack was an act of reprisal rather than a blunder calibrated not to spark war with the US. Iran admitted it was responsible only three days after the attack. International aviation rules give responsibility for investigating the crash to Iran – where the plane came down – which investigators said raised concerns about the independence of the investigation and lessons to be learnt for the sector. “The party responsible for the situation is investigating itself, largely in secret,” Ralph Goodale, the adviser, wrote in the report. “That does not inspire confidence or trust.” The families of those killed expressed frustration that Iran has been able to delay publishing the outcome of the inquiry. Hamed Esmaeilion, a spokesman for The Association of Families of Flight PS752 Victims, said justice had been delayed while they tried to find out exactly what happened. Mr Esmaeilion, whose wife and daughter died in the crash, said: “Iran is smart enough to know that it's in the driving seat. “This is so frustrating, because I think the international community has accepted Iran as a normal regime. “But this is not true. This is not a normal regime. They are criminals, they have done crimes for the last 42 years. “And the world has decided to tolerate them for some reason. When they commit another crime, you see that nobody condemns it.”