Relatives of the 29 people killed in the 1994 RAF Chinook helicopter disaster gathered at the Memorial Garden at Thiepval Barracks in Lisburn on Saturday to lay wreaths, days before the 32nd anniversary of the tragedy.
Des Conroy, whose father Desmond was among those who perished, insisted that authorities are concealing what really happened.
"The truth is being withheld," he said, adding that "a judge-led public inquiry is all that can come of this now".
The families are demanding a full judicial investigation into the incident and the release of all related documents, some of which remain classified for a century.
Alliance MP for Lagan Valley Sorcha Eastwood described it as a "tragedy" that the Government is "still trying to cover this up."
The Chinook helicopter went down on the Mull of Kintyre on June 2, 1994, while travelling from RAF Aldergrove in Northern Ireland to Fort George near Inverness.
All 29 people aboard died, including 25 intelligence specialists and four special forces aircrew.
For years, the two pilots were held responsible for the crash, but this finding was reversed in 2011.
The families of those involved RAF Chinook helicopter disaster have called for an enquiry
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The Chinook Justice Campaign has pointed to recently disclosed Ministry of Defence papers which it says demonstrate that officials knew about significant safety issues with the aircraft.
The campaign group alleges these same officials worked to maintain the official account that blamed the pilots, despite being aware of the helicopter's problems.
Des Conroy spoke of his determination to secure justice for his father, a detective chief superintendent in the Royal Ulster Constabulary.
"It's quite obvious that there were issues with the aircraft all the way back to 1994 and the aircraft should never have taken off," he said.
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The group joined together to mark the 32th anniversary of the tragedy
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He expressed his belief that had his father known about the helicopter's condition, he would never have stepped aboard, nor would any of his colleagues.
"We want justice, we want an apology from the Government that our loved ones were placed on an aircraft that wasn't released for service," Mr Conroy added.
His sister Patricia, who was 22 when their father died, remembered him as "a loving husband, family man" who was hardworking and honest.
"When that happened, the centre of our universe was just like it was just ripped apart," she said, describing the wreath-laying ceremony as "extremely emotional."
Jennifer Balmer-Hornby, who lost her father Major Anthony Robert Hornby just a week before her 10th birthday, explained why a comprehensive public inquiry matters so much to the bereaved families.
"We've had inquiries already, all the inquiries have been about the cause of the crash," she said. "This is not about the cause of the crash. It's about the mountain of evidence to say that that aircraft should never have taken off."
She questioned why authorities would have risked the lives of 29 individuals who were vital to national security.
The families believe crucial information remains hidden from them, with Ms Balmer-Hornby stating they feel "there's more information out there, but they are locking it away".
Ms Eastwood recalled that those who remember the crash also "remember the silence that accompanied afterwards, the useful conspiracy theories that fell into that vacuum due to a lack of information and facts".
She argued the Government has "failed" the victims and their relatives, accusing officials of covering up the truth and dismissing families as liars.
"None of these people are liars, their families were heroes, and the state needs to, at the very least, give them the truth," she said.
The Alliance MP urged swift implementation of the Hillsborough Law, which would compel public officials to be truthful during inquiries.
An MoD spokesman said: "Our thoughts and sympathies remain with the families, friends, and colleagues of all those who died in the Mull of Kintyre crash.
"The MoD continues to engage with the Chinook Justice Campaign (CJC) throughout this process.
"Defence ministers have met with campaign representatives to listen to their concerns, and the CJC also met with the Ministry of Justice victims minister in March.
"The CJC submitted a formal claim for Judicial Review in September 2025, and the MoD is focused on responding fully to that claim and to the allegations it contains.
"We will not be offering comment on issues that are being considered as part of that independent process."