Commission Directive (EU) 2015/996Show full title

Symbols

Quantities are dimensionless unless otherwise stated. Symbols and abbreviations not listed below are used only locally and defined in the text. Subscripts 1 and 2 denote conditions at the start and end of a segment respectively. Overbars denote segment mean values, i.e. average of start and end values.

a

Average acceleration, ft/s²

a_max

Maximum acceleration available, ft/s²

A, B, C, D

Flap coefficients

E, F, G_A,B, H

Engine thrust coefficients

F_n

Net thrust per engine, lbf

F_n/δ

Corrected net thrust per engine, lbf

G

Climb gradient

G′

Engine-out climb gradient

G_R

Mean runway gradient, positive uphill

g

Gravitational acceleration, ft/s²

ISA

International Standard Atmosphere

N *

No of engines supplying thrust

R

Drag-to-lift ratio C_D/C_L

ROC

Segment rate of climb (ft/min)

s

Ground distance covered along ground track, ft

s_TO8

Take-off distance into an 8 kt headwind, ft

s_TOG

Take-off distance corrected for w and G_R , ft

s_TOw

Take-off distance into headwind w, ft

T

Air temperature, °C

T_B

Breakpoint temperature, °C

V

Groundspeed, kt

V_C

Calibrated airpeed, kt

V_T

True airspeed, kt

W

Aeroplane weight, lb

w

Headwind speed, kt

Δs

Still air segment length projected onto ground track, ft

Δs_w

Segment length ground projection corrected for headwind, ft

δ

p/p_o , the ratio of the ambient air pressure at the aeroplane to the standard air pressure at mean sea level: p_o = 101,325 kPa (or 1 013,25 mb)

ε

Bank angle, radians

γ

Climb/descent angle, radians

θ

(T + 273,15)/(T₀ + 273,15) the ratio of the air temperature at altitude to the standard air temperature at mean sea level: T₀ = 15,0 °C

σ *

ρ/ρ₀ = Ratio of air density at altitude to mean sea level value (also, σ = δ/θ)