Extracted from UK CAA publication CAP 437
Offshore Helicopter Landing Areas - Guidance
on Standards;-
Aiming Circle -
Described in other publications as ‘landing circle’ or ‘touch down
marking’; the aiming point for normal landing, so designed that the
pilot’s seat can be placed directly above it in any direction with
assured main and tail rotor clearances.
Full document available at
www.caa.co.uk/docs/33/CAP437.PDF