An RAF Tornado GR4 passed 365m (1,200ft) below a civilian helicopter off Cape Wrath in the north west Highlands, according to a new report.
The incident happened on 7 August when the jet crew were on a training sortie.
The UK Airprox Board, which investigates reports of near misses between aircraft, rated it at the lowest degree of risk.
The RAF pilot reported the incident. The pilot of the AS350 helicopter was unaware of the jet at the time.
