http://www.legislation.gov.uk/id/eudr/2015/996/annex/appendix/B

ANNEX

Appendix BFlight performance calculations

B5TAKEOFF GROUND ROLL

Take-off thrust accelerates the aeroplane along the runway until lift-off. Calibrated airspeed is then assumed to be constant throughout the initial part of the climbout. Landing gear, if retractable, is assumed to be retracted shortly after lift-off.

For the purpose of this document, the actual takeoff ground-roll is approximated by an equivalent take-off distance (into a default headwind of 8 kt), s_TO8, defined as shown in Figure B-1, as the distance along the runway from brake release to the point where a straight line extension of the initial landing-gear-retracted climb flight path intersects the runway.

Image_r00064 — Equivalent takeoff distance

On a level runway, the equivalent takeoff ground-roll distance s_TO8 in feet is determined from

S_{TO8} = \frac{B_{8} \times θ \times {(W ∕ δ)}^{2}}{N \times (F_{n} ∕ δ)}

(B-9)

where

B₈: is a coefficient appropriate to a specific aeroplane/flap-deflection combination for the ISA reference conditions, including the 8-knot headwind, ft/lbf
W: is the aeroplane gross weight at brake release, lbf
N: is the number of engines supplying thrust.

Note:

Since equation B-9 accounts for variation of thrust with airspeed and runway elevation, for a given aeroplane the coefficient B₈ depends only on flap deflection.

For headwind other than the default 8 kt, the takeoff ground-roll distance is corrected by using:

S_{TOw} = S_{TO8} \times \frac{{(V_{C} - w)}^{2}}{{(V_{C} - 8)}^{2}}

(B-10)

where

S_TOw: is the ground-roll distance corrected for headwind w, ft
V_C: (in this equation) is the calibrated speed at takeoff rotation, kt
w: is the headwind, kt

The takeoff ground-roll distance is also corrected for runway gradient as follows:

S_{TOG} = S_{TOw} \times \frac{α}{(α - g \times G_{R})}

(B-11)

where

S_TOG: is the ground-roll distance (ft) corrected for headwind and runway gradient,
a: is the average acceleration along the runway, equal to ${(V_{C} \times \sqrt{σ})}^{2} ∕ (2 \times s_{TOw})$ , ft/s²
G_R: is the runway gradient; positive when taking-off uphill