Rule 5
(d) The land clear rule
An aircraft flying over a congested area of a city, town or settlement shall not fly
below such height as would permit the aircraft to land clear of the congested area
in the event of a power unit failure.
(e) Flying over open air assemblies
Except with the written permission of the CAA, an aircraft shall not fly over an
organised open-air assembly of more than 1,000 persons below the higher of the
following heights:
(i) 1,000 feet; or
(ii) such height as would permit the aircraft to land clear of the assembly in the
event of a power unit failure.
Better have your specs on !