The Rules of the Air Regulations 1996

SECTION VI INSTRUMENT FLIGHT RULES

Instrument Flight Rules

28.—(1) In relation to flights within controlled airspace rules 29, 31 and 32 shall be the Instrument Flight Rules.

(2) In relation to flights outside controlled airspace rules 29 and 30 shall be the Instrument Flight Rules.

Minimum height

29.  Without prejudice to the provisions of rule 5, 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.

Quadrantal rule and semi-circular rule

30.—(1) Subject to paragraph (2), in order to comply with the Instrument Flight Rules, an aircraft when in level flight above 3000 feet above mean sea level or above the appropriate transition altitude, whichever is the higher, shall be flown at a level appropriate to its magnetic track, in accordance with the appropriate Table set forth in this rule. The level of flight shall be measured by an altimeter set:

(a) in the case of a flight over the United Kingdom, to a pressure setting of 1013.2 hectopascals; or

(b) in the case of any other flight, according to the system published by the competent authority in relation to the area over which the aircraft is flying.

(2) An aircraft may be flown at a level other than the level required by paragraph (1) if it is flying in conformity with instructions given by an air traffic control unit or in accordance with notified en-route holding patterns or in accordance with holding procedures notified in relation to an aerodrome.

(3) For the purposes of this rule “transition altitude” means the altitude so notified in relation to flight over such area or areas as may be notified.

TABLE I—

Flights at levels below 24 500 feet

Magnetic Track	Cruising Level
Less than 90°	Odd thousands of feet.
90° but less than 180°	Odd thousands of feet + 500 feet.
180° but less than 270°	Even thousands of feet.
270° but less than 360°	Even thousands of feet + 500 feet.

TABLE II—

Flights at levels above 24 500 feet

Magnetic Track	Cruising Level
Less than 180°	25,000 feet;
	27,000 feet;
	29,000 feet or higher levels at intervals of 4000 feet.
180° but less than 360°	26,000 feet;
	28,000 feet;
	31,000 feet or higher levels at intervals of 4000 feet.

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) (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.

(4) If for the purpose of avoiding immediate danger any departure is made from the provisions of paragraph (3) (as is permitted by article 74(3) of the Order) the commander of the aircraft shall, in addition to causing particulars to be given in accordance with article 74(4) of the Order, as soon as possible inform the appropriate air traffic control unit of the deviation.

(5) 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.

Position reports

32.  In order to comply with the Instrument Flight Rules the commander of an aircraft in IFR flight who flies in or is intending to enter controlled airspace shall report to the appropriate air traffic control unit the time, position and level of the aircraft at such reporting points or at such intervals of time as may be notified for this purpose or as may be directed by the air traffic control unit.