On 2nd October 1953 a major NATO training exercise called "Operation Mariner" was being carried out. Part of the exercise involved four aircraft carrier based Douglas Skyraiders taking off from their carrier, flying as low as possible to avoid detection by ground radar and to make a simulated attack of Scampton airfield in Lincolnshire and return to their carriers. The USS Wasp was one of the aircraft carriers taking part in the exercise, this ship was on patrol many miles out in the North Atlantic. The four Skyraiders took off in two pairs from the deck of the USS Wasp with extra fuel tanks fitted for the long flight, the first pair had to return to the carrier soon after taking off because of radio failure but the second pair continued the flight. The two Skyraiders reached the west coast of Cumbria at low level but found that low cloud was over the mountains. Their orders were to return to the carrier if the weather did not permit low level flying, the aircraft appear to have initially started to fly down Ennerdale Water before realising that taking this low level route was not possible. The lead aircraft made a climbing 180' turn to the left to fly out of the area, clear of the surrounding hills and to return to the carrier. The second aircraft followed but lost sight of the lead aircraft. This second aircraft did not clear the ground while making the turn, it struck Banna Fell and ran along the side of hill and broke up. The pilot was very lucky and escaped with only minor injuries, he was able to walk down to Croasdale but was later treated in Whitehaven Hospital.

Pilot - Lt Thomas Ely McDonald USN, aged 27. Minor injuries.