The father of a US airman killed in a catastrophic military crash over Iraq earlier this month has revealed the haunting final words his son spoke just hours before his death.

Mylo Simmons said his son, Master Sgt. Tyler Simmons, calmly told him over the phone: 'Dad, I don't think I'm coming back from this.'

The emotional account, shared in a televised interview on Monday night, painted a heartbreaking picture of a final conversation between a doting father and his only son.

'He was very calm, told me how much he loved me,' Mylo Simmons said to CNN. 

'He told me to say he loved his dog, Grayson... and you know, he was very insightful.

'Unfortunately he did tell me he didn't think he was coming back,' Simmons said. 'And I told him, "I'm praying for you."'

Hours later, Simmons, 28, was among six US service members killed when a KC-135 refueling aircraft crashed over western Iraq during a mission supporting operations in the region. 

US Central Command said the crash occurred in 'friendly airspace' following an unspecified incident involving two aircraft, adding that it was 'not due to hostile or friendly fire.' 

The other aircraft landed safely and the cause remains under investigation.

For his father, the loss is almost too much to comprehend yet during the interview he remained calm and composed throughout, clinging to his faith and the knowledge that his son died doing what he loved.

'I am a man of faith. Tyler was a man of faith,' Mylo said of his son. 'And I really was hoping that he was going to be wrong, but the solace that I have is he died doing what he loved doing.'

'And I always shared with him, "Live life with no regrets." And knowing Tyler, if he could do it all over again, he'd probably make the same decision because he loved what he did,' his father added.

'I mean, obviously no one wants to die and no one foresaw that or saw that coming, but Tyler was… oh, he was just an amazing son and it was my privilege to be able to be his father.'

Mylo told how Tyler had built his life around aviation.

His father described a young man driven by purpose, someone who had dreamed for years of becoming a boom operator - the critical role responsible for refueling aircraft mid-air - and who hoped one day to transition into a career as a commercial pilot.

'The countless conversations that we had… he dreamed of being the boom operator, which is what he was doing,' Mylo said. 'And ultimately he wanted to retire as a boom operator and then become a commercial pilot - so he was very driven.'

'You know, I frequently told him, "Don't just talk about it, but be about it." And that's exactly what he did.'

Simmons, an Eastmoor Academy graduate from Columbus, was one of several National Guard airmen aboard the doomed aircraft. 

His mother, Cheryl Simmons, previously described the moment uniformed officers arrived at their home to deliver the devastating news.

'When he opened the door, he said, "Oh no," and I jumped up and ran in there and they were lined up out on the porch,' she said. 'You got to be kidding me.'

She broke down in tears as she recounted the moment her only child was taken from her.

Other family members have also remembered him as loving, driven, and deeply devoted to those around him.

'He loved his dog Grayson, he loved his family, his friends,' one relative said. 'He’s just that guy. He would do anything for you.'

A cousin recalled his unmistakable presence: a 'million dollar smile' that lit up every room he entered.

Public officials in Ohio have also paid tribute. 

Columbus Mayor Andrew Ginther said Simmons 'proudly served' his country, while state leaders described him and the other fallen airmen as heroes who made the ultimate sacrifice.

The 121st Air Refueling Wing, to which Simmons belonged, said in a statement: 'It is with a heavy heart that we share the tragic news of the passing of three Airmen from the 121st Air Refueling Wing.

'Our thoughts and prayers are with the family, friends, and fellow Airmen who mourn their loss.'