CAT.POL.A.400 Take-off

LOSS OF RUNWAY LENGTH DUE TO ALIGNMENT

(a)The length of the runway that is declared for the calculation of TODA, ASDA and TORA does not account for line-up of the aeroplane in the direction of take-off on the runway in use. This alignment distance depends on the aeroplane geometry and access possibility to the runway in use. Accountability is usually required for a 90°-taxiway entry to the runway and 180°-turnaround on the runway. There are two distances to be considered:

(1)the minimum distance of the main wheels from the start of the runway for determining TODA and TORA, ‘L’; and

(2)the minimum distance of the most forward wheel(s) from the start of the runway for determining ASDA, ‘N’. Figure 1 Line-up of the aeroplane in the direction of take-off — L and N [Figure or form omitted from this preview — available in the Avioverse workspace library.] Where the aeroplane manufacturer does not provide the appropriate data, the calculation method given in (b) may be used to determine the alignment distance.

(b)Alignment distance calculation [Figure or form omitted from this preview — available in the Avioverse workspace library.] The distances mentioned in (a)(1) and (a)(2) above are:

where: RN = A + WN = WB/cos(90°-α) + WN RM = B + WM = WB/tan(90°-α) + WM X = safety distance of outer main wheel during turn to the edge of the runway Y = safety distance of outer nose wheel during turn to the edge of the runway Note: Minimum edge safety distances for X and Y are specified in FAA AC 150/5300-13 and ICAO Annex 14, 3.8.3 RN = radius of turn of outer nose wheel RM = radius of turn of outer main wheel WN = distance from aeroplane centre-line to outer nose wheel WM = distance from aeroplane centre-line to outer main wheel WM = wheel base α = steering angle.

RUNWAY SLOPE Unless otherwise specified in the AFM, or other performance or operating manuals from the manufacturers, the take-off distance should be increased by 5 % for each 1 % of upslope. However, correction factors for runways with slopes in excess of 2 % should only be applied when:

(a)the operator has demonstrated to the competent authority that the necessary data in the AFM or the operations manual contain the appropriated procedures; and

(b)the crew is trained to take-off on runways with slopes in excess of 2 %.

RUNWAY SURFACE CONDITION The determination of take-off performance data for wet and contaminated runways, when such data is available, should be based on the reported runway surface condition in terms of contaminant and depth.

RUNWAY SURFACE CONDITION Operation on runways contaminated with water, slush, snow or ice implies uncertainties with regard to runway friction and contaminant drag and, therefore, to the achievable performance and control of the aeroplane during take-off, since the actual conditions may not completely match the assumptions on which the performance information is based. An adequate overall level of safety can, therefore, only be maintained if such operations are limited to rare occasions. In case of a contaminated runway, the first option for the commander is to wait until the runway is cleared. If this is impracticable, he/she may consider a take-off, provided that he/she has applied the applicable performance adjustments, and any further safety measures he/she considers justified under the prevailing conditions.