Mystery remained after the inquest into the tragedy of a world-renowned navigation expert who died when a light aircraft crashed into the sea.

Professor David Last, aged 79, of Llanfairfechan, a consultant engineer and a highly experienced pilot, died in November 2019 when a Cessna plummeted nose down into the Irish Sea near Puffin Island, off Anglesey.

The aircraft came down while flying back to Caernarfon airport after a short pleasure flight to the Great Orme headland at Llandudno.

Air accident investigators found no definitive answer for what happened.

Acting senior coroner for North West Wales, Katie Sutherland, recorded an open conclusion at a Caernarfon inquest.

She said: "I simply don’t have the evidence to tell me what occurred and why it occurred.

"There will be unanswered questions here. No inquest can answer every single question.”

Professor Last’s body was recovered from the wreckage, 80ft underwater, 17 days later. He had head and chest injuries.

But there was no medical reason found to explain the crash.

The coroner said there was some evidence of a “positive act” being undertaken.

He was flying alone.

However, a conclusion of suicide couldn’t be presumed.

Professor Last may have been concerned about his wife’s deteriorating health. But the coroner added: “The evidence, on balance, doesn’t lead me to consider he intended (his) death to be the consequence.”

Keith Roberts, an air traffic controller at Caernarfon airport, told the inquest that day Professor Last had been “perfectly fine, his usual self.”

A major search began after the aircraft disappeared from radar and the pilot failed to respond to radio calls.

An Air Accidents Investigation Branch report found: "No definitive cause for the accident could be found.

"There was no evidence of a structural failure leading to the accident and a trial to replicate the final flight profile discounted a full or partial engine failure.

“The trial concluded that it was likely the aircraft required an input on the controls in order to enter and maintain the recorded final descent path.

"The pilot had recently been unwell but there was no evidence of medical incapacitation, although this could not be dismissed as a possible cause.”

Professor Last’s family said previously in a statement: “Professor David Last was a consultant engineer and expert witness specialising in radio navigation and communications systems.

“He was a Professor Emeritus at the University of Bangor, past-President of the Royal Institute of Navigation and a respected figure in the world-wide navigation community.

“He was an experienced, instrument-rated pilot.

"Most importantly to us, he was head of the family, a much-loved father, husband, brother, grandfather, uncle and friend, and we are all heartbroken.”

Following the inquest Prof Last's family released a statement thanking everyone involved in the search plus friends and those from the scientific, academic, navigation and electronic engineering community who have expressed sympathy for the loss of a man they knew as a friend, an outstanding colleague and a "leading light in his field".

"Their thoughts and reflections have been a great comfort.

"We welcome the conclusion of the inquest into our Dad’s death.

"On a personal level this remains a difficult time for the family as we are still coming to terms with the loss of a dearly loved father, grandfather, husband, brother and uncle.

"We thank everyone in advance for respecting our privacy to continue to grieve as a family."