The skeletal remains of an American fighter plane that crashed during the second world war off the Welsh coast, and occasionally emerge ghost-like from the seabed, have been given protected status.

Welsh government officials say the resting place of the Lockheed P-38 Lightning, nicknamed the Maid of Harlech, is the first military aircraft crash site in the UK to be protected for its historic and archaeological interest.

The fighter aircraft is buried around two metres below the seabed off the coast at Harlech in north Wales. When sea and sand conditions are just right it becomes visible in the sand.

Cadw, the Welsh government’s historic environment service, has given the plane scheduled status. It joins castles, abbeys and prehistoric sites as well as buildings and sites connected to the iron, coal and slate industries in Wales that are protected.

The plane crashed in September 1942. It was flown by Second Lt Robert F Elliott, 24, of Rich Square, North Carolina, from Llanbedr on a gunnery practice mission but got into difficulties and had to crash land. The pilot walked away safely from the incident but was reported missing in action a few months later.

His nephew, Robert Elliott, has visited the site and said he was pleased the wreck had been scheduled. “I am honoured and delighted that Cadw has given official recognition of my uncle’s plane as a scheduled monument,” he said. “My uncle was among those brave and expert fighter pilots who served with distinction during the second world war. My visit to the site in 2016 was very moving and emotional.”

The plane has been uncovered three times since it crashed – in the 1970s, in 2007 and most recently in 2014. There are no plans to salvage it.

Matt Rimmer, a local aviation historian, said: “I have been an advocate for the preservation of historic military aircraft crash sites in Wales for over 20 years. I’m thrilled to see the Harlech P-38 scheduled by Cadw.

“I feel it not only acknowledges the significance of this particular aircraft in a historical context, but also the important role played by Wales in the air war against Nazi Germany and the thousands of aircrew from many countries who trained here, many of whom lost their lives either in accidents during training or subsequently in combat.”

The deputy minister for culture, sport and tourism in Wales, Dafydd Elis-Thomas, said: “This site is of international significance and I’m delighted that this designation underlines its special qualities as well as protecting it for the benefit of future generations.

“As we have seen following remembrance events over the weekend, sites such as this represent events which must not be forgotten. Wales will always remember and respect all those who contributed to securing the peace we are so fortunate to enjoy today.”