1 - The Black Vault

As I explained in my last letter, an RAF Police investigation was carried out into the
alleged sonic event over Sheffield on 24 March 1997. Although their report is an
internal document, its conclusions are made available to the public in the same way as
I am doing here.
The RAF Police found that neither a military or a civilian aircraft could have caused
the alleged incident on that night. The radar tapes for the area showed a single
civilian aircraft landing at Manchester airport.
As far as possible explanations for.this i~Cident are concerned, I can only suggest that
a sonic boom may have been caused by a satellite or meteor re-entering the earth's
atmosphere. We sometimes receive reports ofloud explosions, initially thought to
have been caused by military aircraft, being generated by industrial operations at steel
factories.
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