Incident · 13 September 1952 – 25 September 1952 · RAF Topcliffe, North Yorkshire (and the North Sea exercise area)
Exercise Mainbrace sightings (incl. RAF Topcliffe)
Also known as Operation Mainbrace, Mainbrace, Topcliffe
Exercise Mainbrace, NATO's first large naval exercise in the North Atlantic in September 1952, involving some 80,000 personnel and 200 ships, produced several UFO reports from military observers.
On 19 September 1952, Flight Lt. John Kilburn and other RAF personnel at RAF Topcliffe in North Yorkshire saw a silvery disc apparently following a Meteor jet on its approach, swaying like a pendulum, then hovering and speeding away; personnel at nearby RAF Dishforth reported something similar. The sightings were front-page news in British papers, and NATO later confirmed that Danish aircrew had seen a comparable silvery disc over the North Sea the same day.
According to Edward Ruppelt of Project Blue Book, the Mainbrace sightings led the RAF to take UFOs seriously, and the UK Air Ministry began investigating reports on a permanent basis in 1953. No explanation was published.
Sources: Wikipedia · Project 1947 · Ruppelt, The Report on Unidentified Flying Objects (1956)
Facts and claims
- claimed During NATO's first big naval exercise in the North Atlantic (some 80,000 personnel, 200 ships), several military observers reported unidentified objects. Source: en.wikipedia.org (archived)
- claimed On September 19, 1952, Flight Lt. John Kilburn and other RAF personnel at RAF Topcliffe saw a silvery disc following a Meteor jet on approach, swaying like a pendulum, then hovering and speeding away. On September 20, journalist Wallace Litwin photographed a silver sphere from the deck of USS Franklin D. Roosevelt. — John Kilburn Source: project1947.com (archived)
- claimed According to Edward Ruppelt (Project Blue Book), these sightings led the RAF to take UFOs seriously. The UK Air Ministry began investigating reports on a permanent basis in 1953. Source: gutenberg.org (archived)
Connected files
Programs
- Project Blue Book (discussed by) — Blue Book's Edward Ruppelt said the sightings led the RAF to take UFOs seriously
People
- John Kilburn (witnesses)
Mentioned in this file
- Ministry of Defence (UK) (Organization)
- Edward J. Ruppelt (Person)
- The Report on Unidentified Flying Objects (Book)
Mentioned in documents and records
More incidents
- Haneda AFB radar-visual sighting
- Chorwon F-94 engagement
- Wonsan–Sunchon B-29 sightings
- Republic of Korea Air Force Phantoms encounter
- Cagliari-Elmas orange sphere seen by Army and Air Force pilots (Italy, 1977)
- Canary Islands luminous halo seen by Navy, Air Force and airline crews (Spain, 1976)