Flight plan and air traffic control clearance
31.—(1) In order to comply with the Instrument Flight Rules, before an aircraft either takes off from a point within any controlled airspace or otherwise flies within any controlled airspace the commander of the aircraft shall cause a flight plan to be communicated to the appropriate air traffic control unit and shall obtain an air traffic control clearance based on such flight plan.
(2) The flight plan shall contain such particulars of the intended flight as may be necessary to enable the air traffic control unit to issue an air traffic control clearance, and for search and rescue purposes.
(3) Without prejudice to paragraph (2), any flight plan for a flight within Territory reduced vertical separation minimum airspace shall state whether or not the aircraft is equipped with height keeping systems as required by articles 48 or 49.
(4) (a) Subject to sub-paragraph (b), the commander of the aircraft shall fly in conformity with:
(i)the air traffic control clearance issued for the flight, as amended by any further instructions given by an air traffic control unit; and
(ii)the holding and instrument approach procedures notified in relation to the aerodrome of destination, unless he is otherwise authorised by the air traffic control unit there.
(b)The commander of the aircraft shall not be required to comply with sub-paragraph (a) if:
(i)he is able to fly in uninterrupted Visual Meteorological Conditions for so long as he remains in controlled airspace; and
(ii)he has informed the appropriate air traffic control unit of his intention to continue the flight in compliance with Visual Flight Rules and has requested that unit to cancel his flight plan.
(5) If for the purpose of avoiding immediate danger any departure is made from the provisions of paragraph (4) (as is permitted by article 84(3) of this Order) the commander of the aircraft shall, in addition to causing particulars to be given in accordance with article 84(4) of this Order, as soon as possible inform the appropriate air traffic control unit of the deviation.
(6) The commander of the aircraft after it has flown in controlled airspace shall, unless he has requested the appropriate air traffic control unit to cancel his flight plan, forthwith inform that unit when the aircraft lands within or leaves the controlled airspace.