1977 February 4th - Things that went bump in the night first annoyed then baffled Somerset and Bristol in the winter of 1976/77.
Not just bump. . .but Bump-Bump. On some nights the double detonation was heard from Taunton to Totterdown. What on earth was going on? The story of those funny bumps started in Somerset in November, 1976 when folk living in North Petherton became alarmed by a double detonation that seemed to come shortly after 9 p.m. most evenings. By November 14th they had called in the police, as the Post reported the next day. 'Inspector John Thou
less of Sedgemoor police said: 'This is a very puzzling affair.
The accuracy of the reports was completely confirmed by the constable we sent out to North Petherton to check.
' 'We too have made widespread inquiries without result. ' 'An extraordinary feature of the matter is that these regular rumbling noises have been reported from the Royal Ordnance factory at Puriton, Yeovilton, Wellington and even as far away as Crediton.' '
Locals had pointed the finger at both the Royal Naval Air Station and the ordnance factory. Not guilty, they said. They'd heard them too. The Post made its own investigation and discovered that some of those mysterious bumps seemed to coincide with incoming transatlantic flights by British Airways Concordes. It didn't explain all the sounds, and anyway, BA said, their Concordes slowed down to subsonic well be
fore reaching the coastline.
The Post dug a little deeper and found that some bumps came at about the time Air France Concordes bound
for Paris were passing our shores. A Civil Aviation Authority expert was sceptical. 'The usual carpet
for hearing sonic booms is about 20 miles. At 30 miles the sound has disappeared or very nearly so. Yet this noise is being heard at far greater distances'.
At which point Bristol University decided to step in to nail the noise once and
forall. A group sat in Somerset gardens, recorded the sounds and went to work. On February 4th, 1977, they were ready and they called a press conference. The Bump Boffins pinned the blame for disturbing the peace of the West Country evening firmly on Bristol's wonder plane. 'As Concorde approaches Europe— both Air France flights to Paris and British Airways flights to Heathrow—it flies supersonic until within 40 miles of coastlines.
'But before the plane decelerates to subsonic speeds it is making the typical double bang sonic boom heard from all supersonic planes. 'And that bang bounces—either off the sea and strong upper atmosphere winds or off the strong upper atmosphere winds directly—and comes back to earth giving the typical deep rumble of the Somerset bumps.
'Dr Tom Lawson, reader in industrial aerodynamics said: 'Of 584 reports from the public, only about a dozen people were concerned or worried'. 'He said the pressure of the Somerset Bumps was equivalent to the pressure of an object travelling at 2 mph—and the sound is the equivalent of a car door slamming about 50 yards away.' So now we knew . . .