ICWales -- HE family of the Welsh serviceman killed when a Hercules plunged into the Iraqi desert last night paid tribute to his dedication to the RAF.

Flight Sergeant Mark Gibson couldn't wait to follow his father into the service. As soon as he left school at 18, he realised his boyhood ambition by joining up.

Air-loadmaster Mark, 34, served with 47 Squadron based at RAF Lyneham in Wiltshire and lived in Swindon with his wife Sheila and young daughter Poppy.

He was awarded Operational Service Medals for Sierra Leone, Afghanistan and Iraq.

Mark went to school in Cardiff before the family moved to West Wales where his father Sam was based at RAF Brawdy, near St Davids, Pembrokeshire. Mark has two younger brothers - one Neil is also a loadmaster in the RAF.

Mark's death stunned many of his family who did not even know he was in Iraq.

He was one of 10 servicemen who died in Sunday's crash and who were named by the Ministry of Defence yesterday.

A senior investigating officer arrived in Iraq yesterday to find out how the crash happened, amid claims by militant groups that they shot the aircraft down.

In a message to the men's families sent via Defence Secretary Geoff Hoon, the Queen said she was saddened by the incident and conveyed her "deepest sympathy".

Mark's cousin, nurse Clare Bateman-Jones, said, "He was very laid back and very funny.

"But he was very dedicated to his job in the RAF and to his family. He was as kind a person as you could hope to meet.

"It has come as a great shock to us as we did not even know he was over there.

"Mark loved being in the RAF. He couldn't wait to join up when he left school.

"He was always such a happy guy, easy to be around and very laid back. It is so terribly sad."

His father Sam, now retired, and brothers Neil and Paul were yesterday comforting each other.

An MoD statement last night said, "Throughout his career, Mark managed to combine his intelligent, hard-working approach to professional matters with an ebullient enthusiasm that made him a pleasure to work with."

Relatives of Acting Lance Corporal Steven Jones, 25, the only soldier on board, said he would "forever be in the hearts of those that knew him best".

A spokesman for the Prime Minister said it was a "very sad and painful time" and Mr Blair's thoughts were with the families.

Eight of the men who died were based at RAF Lyneham in Wiltshire and the Princess Royal yesterday paid a private hour-long visit to the base.

There she met members of 47 Squadron, which lost five of its number in the crash, as well as staff assisting the bereaved families.

Floral tributes and notes of condolence continued to be placed by well-wishers at Lyneham during the day.

Group Captain Paul Oborn, station commander at Lyneham, said everyone there felt the loss "intensely", adding that those who died were "one of our best" crews.

The aircraft was captained by Flight Lieutenant David Stead, 35, a married pilot serving with 47 Squadron who a neighbour said had recently had a second child.

Flight Lieutenant Andrew Smith, Flight Lieutenant Paul Pardoel, Master Engineer Gary Nicholson and Flight Sergeant Mark Gibson also belonged to the squadron.

Flt Lieut Pardoel, 35, a navigator, was originally from Australia and his death had been announced on Monday by officials in his home country.

His father John said he had been living in England with wife Kellie and children Jordan, seven, Jackson, five, and India, two.

Flt Lieut Smith, 25, a pilot, was single, while Master Engineer Nicholson, 42, an air engineer, was divorced.

Chief Technician Richard Brown, 40, Sergeant Robert O'Connor, 38, and Corporal David Williams, 37, served with the Engineering Wing at Lyneham.

Chief Technician Brown was divorced and an avionics specialist while Sgt O'Connor, an engineering technician, was single and Cpl Williams was married and a survival equipment fitter.

Squadron Leader Patrick Marshall, 39, was a divorced staff officer who served with Headquarters Strike Command in High Wycombe.

The family of Acting L/Cpl Jones, who was single, described him as adventurous and fun loving with a "wicked sense of humour".

Earlier yesterday it emerged that investigations into what happened, hampered by marshy terrain and hostile local forces, could take weeks.

An MoD spokesman described as speculation reports that there may have been a bomb on board the Hercules.

One Iraqi militant group claimed on Monday on a website that it had downed the plane with an anti-tank missile while a second produced a video which purported to show it being shot down.

The relatively slow, low-flying Hercules, renowned for its reliability, crashed in clear conditions 25 miles north-west of Baghdad.

It was the biggest single loss of life to hit UK forces since military action in Iraq began.