IF UFOs existed, airline pilots would probably be the people most likely to see them, track them and, with the help of their sophisticated equipment, gather the reliable technical data that makes a tall tale less easy to dismiss. It was Graham Sheppard’s contention that pilots had been sighting unidentified craft experiencing regular near-misses for decades.

Sheppard was a telecommunications engineer and civil pilot who alarmed his superiors by speaking out about such experiences and, as he claimed, the danger to civil aviation of near-collisions and panic reactions in the face of unidentified craft.

His discussions with the press about his experiences led to his being censured in 1993, with the threat of dismissal from British Airways if he continued to air his views. After this he remained circumspect until his retirement. Thereafter he became a popular speaker at UFO conferences and seminars.

Sheppard was born in Pembrokeshire in 1942. His interest in UFOs was first aroused when, aged 11, he spotted something odd in the sky. Although he had a dream of becoming a pilot himself, he did not begin flying commercial aircraft until 1966. First he worked as a telecommunications engineer on a prototype modem — a room-sized technologically advanced device. During his time working for the Post Office he was also stationed at the Satellite Earth Station at Goonhilly Downs on the Lizard in Cornwall.

He subsequently trained at the BEA/BOAC College of Air Training at Hamble, Southampton, and graduated to fly as first officer on BOAC’s Vickers Vanguard aircraft. In the next 30 years he flew almost every kind of aircraft, both passenger and cargo, for BOAC and then, on its amalgamation with BEA, for British Airways (BA). In the mid-1970s Sheppard would take a two-year sabbatical in Africa, flying a twin-engined Britten-Norman Islander for Zambia’s flying-doctor service; he later flew domestic routes in Malawi.

In 1967, on a flight from Scotland to London, Sheppard’s crew were warned of “high-speed opposite direction traffic, identity unknown”. Almost immediately Sheppard saw, so he reported, below him and about 300 metres to the west, a shining disc-shaped object which passed at a speed he estimated as being 1,300kmh. That same year, on a night flight to London from Gibraltar, he and his crew recorded what appeared to be an aerobatic display by two unidentified craft. The two objects were confirmed but not identified by radar in Bordeaux.

(Richard Haines, a Nasa research scientist and science director of the National Aviation Reporting Centre on Anomalous Phenomena (Narcap) states that since the early days of civil aviation pilots worldwide have made about 3,400 reports of unidentified craft.)

After speaking to journalists about his concerns over near-misses, Sheppard was summoned to the office of Lloyd Griffiths, British Airways’ chief pilot for the Boeing 757 and 767 fleets. The correspondence that followed stated that “BA is not putting its collective head in the sand on this topic” but gave warning of the “media reaction involving ridiculing of your views and the subsequent damage of your image as a BA captain”. It stated that Sheppard should be in no doubt about the “likely repercussions” of further disclosures.

He had, however, broken the silence and changed the atmosphere immeasurably. On February 2, 1995, The Times reported that a near-miss between a BA 737 with 60 passengers on board and an illuminated wedge-shaped object at 13,000 feet above the Pennines was under formal investigation by the Civil Aviation Authority. The conclusion, a year later, stated that: “Despite exhaustive investigation the reported object remains untraced”, and the Joint Airmiss Working Group (JAWG) stated that it hoped this case “will encourage pilots who experience unusual sightings to report them without fear of ridicule,” added that the pilots, Roger Wills and Mark Stuart, were the “latest in a long line of pilots to have faced the unmentionable”. The pilots in this case had taken no evasive action; responding to gut instinct in other such cases has been known to stall aircraft. Knowing this, Sheppard briefed the JAWG in 1995, a year after his retirement from BA.

In 1989 he met and befriended the UFO researcher Timothy Good. In his book Unearthly Disclosure (2000), Good included an account of an experience in which, while flying a Cessna 172 from San Juan to Mayagüez, Puerto Rico, Sheppard, after passing over the Arecibo radio telescope, suddenly found himself impossibly far off course. His instruments — still, apparently, functioning normally — had recorded that he had passed over hills 3,900 feet high while flying at a constant 2,200ft.

Sheppard was kept busy on the lecture and conference trail until incapacitated by myelofibrosis. He was a musical polyglot, able to play many instruments, but with a particular skill for jazz clarinet and saxophone. His abilities as a raconteur, and his ability to be always credible, as well as immensely likeable, brought great conviction, as well as entertainment, to any discussion of the unexplained in which he participated.

He is survived by his wife, Margaret, and by two sons from a previous marriage.

Graham Sheppard, airline pilot, was born on December 11, 1942. He died on August 24, 2005, aged 62.