Neil Davidson was only 21 when his life ended.

It ended, but his final moments and actions in life effectively saved the lives of many others.

Young Flight Sergeant Neil Douglas Davidson, who was born in Porangahau and later went to Hastings Boys' High School, died at the controls of his Lancaster bomber - one of seven of 75 NZ bomber squadron's 28 aircraft which had set out on raids into Germany on that night of July 21, 1944, which did not return.

He was the youngest of the crew, and the only Kiwi aboard, and his death left more than an emotional vacuum for his family back in New Zealand - it left a mystery as to what had happened in the final moments of his life.

Devastated by news of Neil's death, the family had been left in limbo with the news only that he had gone missing in action - somewhere in Holland.

There was a clear military line through the family.

As Neil's brother Don Davidson explained, their dad was with the Wellington East Coast Mounted Rifles in WWI. He was wounded and bore the injury for the rest of his life. He also lost a brother in France and another was also wounded.

Don said his other brother, Keith, was with the New Zealand Army in the Solomon Islands fighting the Japanese. He took a serious chest wound but survived, and the family was delighted to recently help him celebrate his 90th birthday.

But there were to be no more birthdays for Neil after his Lancaster was taken out of the sky by a German night-fighter near the town of Kessel, beside the River Maas, back in 1944.

There was no body uncovered - and no grave.

But in recent years the first steps in unravelling what happened to Neil Davidson emerged.

In May 2011, Don came across an appeal for information, from a corporal in the RAF, seeking the relatives of the lost aircrew.

Don, and his sister Shirley, were also contacted by the Ohakea-based secretary of 75 Squadron, Glen Turner, and told of a planned memorial service for the lost crew.

The instigator of the service was a Welsh serviceman and historian called Barrie Davies who lived in Holland.

He had researched the history of the crash and was able to fill in the missing details for the family.

It was originally thought the Lancaster had crashed into the Maas river, going by what some Kessel residents had thought, but it transpired there was no wreckage.

"It had been blown to smithereens," Don said.

"By the explosion of seven tonnes of bombs and gallons of aviation fuel."

The explosion blew out pretty well every window in the town, although most residents were in underground shelters when it happened.

Don was told that his brother had clearly had enough control over the bullet-riddled bomber to steer it away from the town and toward the river. His heroic last moments saved many, many lives.

Don and Shirley travelled to Holland last July, along with other family members, to attend a memorial unveiling to their brother, and the rest of the aircrew who died.

Mr Davies took Don and Shirley to the site where the bomber, with young Neil Davidson fighting at the controls, succumbed to the attack and exploded - and explained how the tail section was separated and fell to the ground as the rest of the aircraft disintegrated in flames.

"He showed us the field where the tail had separated from the rest of the plane and the exact spot where the explosion had occurred," Don said.

"It was too much for me. I wept unashamedly for quarter of an hour ... after 67 years we had learned the true story."

The service was attended by Dutch, German and British dignitaries, and Don said the emotional and thoughtful ceremony bore what he called "amazing Anzac messages for young and old".

The Lord Mayor of Kessel, Wilma Delissen-van Tongerlo, said the story of the young men who died that night was a story strongly enmeshed in the eventual freedom of Holland.

"Liberators who came from far - men in the prime of their lives who ventured their life and future to secure the freedom of others."

Don described the four days spent in Kessel as "very special" and he and Shirley were proud when some locals approached and asked where they had come from - and then expressed amazement, and respect, that young men from the other side of the world had stepped forward and entered a battle for their freedom.