33. (1) Subject to paragraphs (2) and (3), an aircraft shall not fly at a height of less than 1,000 feet above the highest obstacle within a distance of 5 nautical miles of the aircraft unless—
(a)it is necessary for the aircraft to do so in order to take off or land;
(b)the aircraft flies on a route notified for the purposes of this rule;
(c)the aircraft has been otherwise authorised by the competent authority in relation to the area over which the aircraft is flying; or
(d)the aircraft flies at an altitude not exceeding 3,000 feet above mean sea level and remains clear of cloud and with the surface in sight and in a flight visibility of at least 800 metres.
(2) The aircraft shall comply with rule 5.
(3) Paragraph (1) shall not apply to a helicopter that is air-taxiing or conducting manoeuvres in accordance with rule 6(i).