The Royal Navy has named the serviceman killed in a night-flying training exercise in the English Channel on 4 September as Lt Rhodri Leyshon.

Lt Leyshon’s family released a statement on Friday saying he was “immeasurably loved by his parents, siblings, partner, friends and family and he was devoted to them”.

A Merlin Mk4 helicopter Lt Leyshon was in ditched – a deliberate emergency landing on water – with three servicemen on board on Wednesday near Dorset, the Navy said.

Defence Secretary John Healey said an investigation into the accident had already started.

“We are all so very proud of the talented, passionate, strong and loyal man he was. We will always have him in our hearts. Our wonderful boy,” the family said.

“Our lives will never be the same without him.”

The two other crew members on board the helicopter at the time of the incident were not seriously injured.

Lt Leyshon joined the Wales University Royal Naval Unit, which trains students, in 2010 and was commissioned into the Royal Navy in 2014. He undertook flying training, specialising as a Commando Aviator, and completed a number of overseas deployments, including to the Caribbean, USA and Norway.

For the past 18 months, Lt Leyshon had served in 846 Naval Air Squadron. The Navy said he was one of the Commando Helicopter Force’s “most trusted and highly capable aircraft captains and instructors, having honed his skills undertaking some of Defence’s most specialist aviation tasks”.

Colonel Mark Johnson, Commanding Officer of Commando Helicopter Force at Yeovilton, said in a statement: “It’s immensely sad that we lost one of our family.”

“Lt Leyshon was a consummate professional and a shining light with a bright future. He epitomised our team spirit and his loss leaves a huge hole in all our hearts.”

Air Vice-Marshal Alastair Smith, Commander of Joint Aviation Command, said he had flown with Lt Leyshon a few days ago and attested to his professionalism as a pilot and his warmth as a character.

“He will be sorely missed,” he said.