Commission Directive (EU) 2015/996Dangos y teitl llawn

B6 CLIMB AT CONSTANT SPEED U.K.

This type of segment is defined by the aeroplane's calibrated airspeed, flap setting, and the height and bank angle at its end, together with the headwind speed (default 8 kt). As for any segment, the segment start parameters including corrected net thrust are put equal to those at the end of the preceding segment — there are no discontinuities (except of flap angle and bank angle which, in these calculations, are allowed to change in steps). The net thrusts at the segment end are first calculated using the appropriate equation from B-1 to B-5. The average geometric climb angle g (see Figure B-1) is then given by

(B-12)

where the over-bars denote mid-segment values (= average of start-point and end-point values — generally the mid-segment values) and

K

is a speed-dependent constant equal to 1,01 when V_C ≤ 200 kt or 0,95 otherwise. This constant accounts for the effects on climb gradient of climbing into an 8-knot headwind and the acceleration inherent in climbing at constant calibrated airspeed (true speed increases as air density diminishes with height).

R

is the ratio of the aeroplane's drag coefficient to its lift coefficient appropriate to the given flap setting. The landing gear is assumed to be retracted.

ε

Bank angle, radians

The climb angle is corrected for headwind w using:

(B-13)

where γ_w is the average climb angle corrected for headwind.

The distance that the aeroplane traverses along the ground track, Δs, while climbing at angle γ _w , from an initial altitude h ₁ to a final altitude h ₂ is given by

(B-14)

As a rule, two distinct phases of a departure profile involve climb at constant airspeed. The first, sometime referred to as the initial climb segment is immediately after lift-off, where safety requirements dictate that the aeroplane is flown at a minimum airspeed of least the takeoff safety speed. This is a regulated speed and should be achieved by 35 ft above the runway during normal operation. However, it is common practice to maintain an initial climb speed slightly beyond the takeoff safety speed, usually by 10-20 kt, as this tends to improve the initial climb gradient achieved. The second is after flap retraction and initial acceleration, referred to as continuing climb.

During the initial climb, the airspeed is dependent on the takeoff flap setting and the aeroplane gross weight. The calibrated initial climb speed V_CTO is calculated using the first order approximation:

(B-15)

where C is a coefficient appropriate to the flap setting (kt/√lbf), read from the ANP database.

For continuing climb after acceleration, the calibrated airspeed is a user input parameter.