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(a) A RESA must extend from the end of the runway strip –
(1) to at least 90 metres; or
(2) if practicable –
(i) for a runway that has a code number 3 or 4 to at least 240 metres; or
(ii) for an instrument runway that has a code number 1 or 2 to at least 120 metres.
(ab) Despite paragraph (a), if a RESA is required for a non-instrument runway that has a code number 1 or 2, the RESA must extend if practicable from the end of the runway strip to at least 30 metres.
(ad) Factors which may be relevant to the practicability of a particular RESA length may include but are not limited to –
(1) any physical or other difficulties that may affect or constrain the proposal or site;
(2) whether and if so at what expected cost such difficulties may be overcome;
(3) whether the costs are proportionate to the benefits a holder of an aerodrome operator certificate may expect from any development of which the RESA forms part;
(4) the results of a cost benefit analysis; and
(5) the results of an aeronautical study.
(b) The width of a RESA must—
(1) be at least twice the width of the associated runway and be positioned symmetrically on either side of the extended centre line of the runway; and
(2) where practicable, be equal to the width of the graded portion of the associated runway strip.
(c) A RESA must be constructed to—
(1) provide a cleared and graded area to reduce the risk of damage to an aeroplane that undershoots or overruns the runway; and
(2) where practicable, be clear of any object which might endanger an aeroplane that undershoots or overruns the runway.
(d) A RESA must not penetrate the approach or take-off climb surface for the runway.
(e) If a RESA has a longitudinal slope—
(1) any downward slope must not exceed 5%; and
(2) slope changes must be as gradual as practicable; and
(3) abrupt changes or sudden reversals of slopes must be avoided.
(f) If a RESA has a transverse slope—
(1) any upward or downward slope must not exceed 5%; and
(2) slope changes must be as gradual as practicable.
