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Old 9th Aug 2010, 12:38
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Parkbremse
 
Join Date: Mar 2003
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Thanks for the reference, this what i was looking for and actually undermines my point. (But stated in clearer english i suppose...)

(c)If the take-off distance does not include a clearway, the take-off run is equal to the take-off distance. If the take-off distance includes a clearway –

(1)The take-off run on a dry runway is the greater of –

(i)The horizontal distance along the take-off path from the start of the take- off to a point equidistant between the point at which VLOF is reached and the point at which the aeroplane is 11 m (35 ft) above the take-off surface, as determined under CS 25.111 for a dry runway; or
(ii)115% of the horizontal distance along the take-off path, with all engines operating, from the start of the take-off to a point equidistant between the point at which VLOF is reached and the point at which the aeroplane is 11 m (35 ft) above the take-off surface, determined by a procedure consistent with CS25.111. (See AMC 25.113(a)(2), (b)(2) and (c)(2).)

(2)The take-off run on a wet runway is the greater of –

(i) The horizontal distance along the take-off path from the start of the take- off to the point at which the aeroplane is 4,6 m (15 ft) above the take-off surface, achieved in a manner consistent with the achievement of V2 before reaching 11 m (35 ft) above the take-off surface, determined under CS 25.111 for a wet runway; or
(ii)115% of the horizontal distance along the take-off path, with all engines operating, from the start of the take-off to a point equidistant between the point at which VLOF is reached and the point at which the aeroplane is 11 m (35 ft) above the take-off surface, determined by a procedure consistent with CS 25.111. (See AMC 25.113(a)(2).)
So:
Dry Runway: TOR = Start of T/O Run until point equidistant between v_lof and the point where 35ft is reached. At that point your height will be 15ft. (paragraph c1(i) )

Wet Runway: TOR = Start of T/O Run to the point where 15ft are reached. (paragraph c2(i) )

Exactly the same. Note that it says Take-Off Run and not Take-Off Distance The difference is that in the WET case your Take-Off is completed at 15ft screenheight so TOR = TOD which is practically the same as disregarding the clearway.
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