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The following procedure must be carried out by a holder of an air operator certificate under rule 121.221(b)(2) for calculating the landing distance where a runway is dry:
(a) A holder of an air operator certificate must ensure that, for each aeroplane it operates, the landing weight for the estimated time of landing allows a full stop landing on a dry runway from a point 50 feet above the threshold within—
(1) 60% of the landing distance available for a turbojet or turbofan powered aeroplane; and
(2) 70% of the landing distance available for a propeller-powered aeroplane.
(b) When calculating the landing weight under paragraph (a), the certificate holder must take account of—
(1) aerodrome elevation; and
(2) ambient temperature at the aerodrome; and
(3) the type of runway surface and the runway surface condition; and
(4) the runway slope in the direction of landing; and
(5) not more than 50% of the reported headwind component or not less than 150% of the reported tailwind component.
(c) The certificate holder must, for an aeroplane to land as specified in paragraphs (a) and (b), assume that the aeroplane will land on the most favourable runway taking into account—
(1) the forecast meteorological conditions; and
(2) surrounding terrain; and
(3) approach and landing aids; and
(4) obstacles within the missed approach flight path.
(d) If the certificate holder is unable to comply with paragraph (c) for the destination aerodrome, the certificate holder may dispatch an aeroplane if an alternate aerodrome is designated that permits compliance with paragraphs (a), (b), and (c).
A holder of an air operator certificate must carry out the following procedure under rule 121.221(b)(2) for calculating the landing distance where a runway is wet or contaminated:
(a) A holder of an air operator certificate must ensure that, for each aeroplane it operates—
(1) when the appropriate weather reports or forecasts or a combination of them, indicate that the runway at the estimated time of arrival may be wet, the landing distance available is at least 115% of the landing distance required by paragraph D.1; and
(2) when the appropriate weather reports or forecasts or a combination of them, indicate that the runway at the estimated time of arrival may be contaminated, the landing distance available is at least—
(i) 115% of the landing distance required by paragraph D.1; or
(ii) the landing distance determined in accordance with contaminated-landing-distance data.
(b) A landing distance on a wet runway shorter than that required by paragraph (a), but not less than that required by paragraph D.1, may be used if performance data allows a shorter landing distance on wet runways.
