Mid 80's, think it was June 86, BAH sent over one of its 234's to display at the annual RAF Buchan open day.
On this particular day, there was a cricket match in progress in the playing field next door. Nothing untoward happened, until the end of the display. The crew demonstrated the 234's capability of climbing, vertically, like a love sick angel, whilst at the same time demonstrating a max-rate yaw turn.
The downwash from the chinook caused absolute chaos in the cricket field - tables, chairs, people rolling around the field.
Absolute corker of a display, can still hear that distinctive chinook whine, as it shot off into the heavens, before disappearing back to ABZ.
The helicopter displays were somewhat muted at subsequent Open Days.