RAF Topcliffe disc (Exercise Mainbrace)
- Date
- 19 Sep 1952
- Place
- RAF Topcliffe and RAF Dishforth, near Thirsk, North Yorkshire, England, United Kingdom
- Record
- Curated case
- Assessment
- Contested
- Evidence strength
What was reported
On 19 September 1952, during NATO's Exercise Mainbrace, RAF personnel including Flight Lieutenant John Kilburn of 269 Squadron watched a silvery circular object follow a Meteor jet as it descended, swing 'like a falling sycamore leaf', stop, rotate and accelerate away. Accounts differ on whether the observers were Shackleton crews at Topcliffe or ground staff at nearby Dishforth, and NATO later said Danish aircrew had seen a silver disc over the North Sea the same day. The sighting made newspaper front pages; the Air Ministry told the press it might have been a weather balloon, and an RAF officer suggested a smoke ring from a jet engine relit after a flame-out. The personnel's occurrence reports are held at The National Archives, and the episode helped push the Air Ministry to set up a standing UFO desk.
What officials concluded
Tentative explanation
Air Ministry to the press: possibly a weather balloon; an RAF officer suggested a jet-engine smoke ring
Strongest ordinary reading
none established; a balloon or an exhaust ring are the conventional candidates
Evidence profile
- Yes: Visual
- No: Infrared
- No: Radar
- No: Video
- No: Photo
- No: Film
- No: Audio
- No: Night vision
- No: Other sensor
- No: Civilian
- Yes: Military aircrew
- Yes: Military ground
- No: Airline crew
- No: Sensor operator
- No: Law enforcement
- No: Scientist
- No: Astronaut
- No: Intelligence official
- No: Other
- No: Light only
- No: Orb or sphere
- Yes: Disc
- No: Triangle
- No: Cylinder
- No: Cube
- No: Other shape
- No: Physiological
- No: Physical trace
- No: Electromagnetic
- No: Sound
- No: Silent
Outside sources
- Wikipedia: Operation Mainbraceen.wikipedia.org
- History.com: the UK UFO sightings during Mainbracehistory.com
On the map
54.21° N, 1.38° W, plotted at the site
Show on the map