# The Rules of the Air Regulations 1990, Paragraph 25: Minimum height


Without prejudice to the provisions of rule 5 of these Rules, in order to comply with the Instrument Flight Rules an aircraft shall not fly at a height of less than 1000 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 is flying on a route notified for the purposes of this rule;
(c) the aircraft has been otherwise authorised by the competent authority; or
(d) the aircraft is flying at an altitude not exceeding 3000 feet above mean sea level and remains clear of cloud and in sight of the surface.

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Source: https://www.legislation.gov.uk/uksi/1990/2241/schedule/paragraph/25 (the official version)
Page: https://openlegislation.uk/rules-of-the-air-regulations-1990/schedule/paragraph-25
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.