B11LANDING APPROACHU.K.
The landing approach calibrated airspeed, VCA , is related to the landing gross weight by an equation of the same form as equation B-11, namely
where the coefficient D (kt/√lbf) corresponds to the landing flap setting.
The corrected net thrust per engine during descent along the approach glideslope is calculated by solving equation B-12 for the landing weight W and a drag-to-lift ratio R appropriate for the flap setting with landing gear extended. The flap setting should be that typically used in actual operations. During landing approach, the glideslope descent angle γ may be assumed constant. For jet-powered and multi-engine propeller aeroplanes, γ is typically – 3°. For single-engine, propeller-powered aeroplanes, γ is typically – 5°.
The average corrected net thrust is calculated by inverting equation B-12 using K = 1,03 to account for the deceleration inherent in flying a descending flight path into an 8-knot reference headwind at the constant calibrated airspeed given by equation B-24, i.e.
For headwinds other than 8 kt, average corrected net thrust becomes
The horizontal distance covered is calculated by:
(positive since h1 > h2 and γ is negative).