Equation Characters, Abbreviations, Expressions

The list is arranged alphabetically; Greek characters are at the bottom.
 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Greek

A
Wing aspect ratio, A = b²/ SW . It is a requirement or taken from statistics.
 AEO
All Engines Operating. Normal flight situation.
 ASD
Accelerate Stop Distance. The maximum distance the aircraft covers while the start-break off situation at takeoff field.
 A t
Total aircraft wetted area, used in the crise condition (not in this module).
 b
Wing span of the main wings.
 cD, 0
Drag coefficient at zero lift.
cD, flap
Flap drag coefficient.
cD, gear
Landing gear drag coefficient.
cD, slat
Slat drag coefficient.
 cL,m
Lift coefficient for (L / D)max.
 cL,max,L
Maximum lift coefficient at landing. Determined through the high lift system of the aircraft.
 cL,max,TO
Maximum lift coefficient at takeoff. Estimated determination: cL,max,TO = 0.8×cL,max,L
 DTO
Drag of aircraft at takeoff.
e
Oswald's airplane efficiency factor, e = 1.0 for a wing with elliptical span loading and less than 1.0 for all other span loadings.
 
  To top of this page
  Back to previous page
 g
Acceleration of fall, g = 9.81 m/s².
 kAPP
A calculated factor describing the ratio between approach speed and safety landing field length. LOFTIN 1980 determined this factor with 1.7.
 kL
A calculated factor to simplify the landing field equation. According to statistic determinations with existing aircraft this factor is 0.107 kg/m³.
 kTO
A calculated factor to simplify the takeoff field equation. According to statistic determinations with existing aircraft this factor is 2.34 m³/kg.
 L'
Scale parameter, L' = (cruise speed in [kn] × root chord in [ft] ) / 1.63×104.
 (L / D)max
Maximum lift-drag ratio, determined in the cruise condition (not in this module).
 l / d
Fuselage length / fuselage diameter.
 LDA
Landing Distance Available. The maximum field length at the airport for landing.
 LTO
Lift of aircraft at takeoff. According to the balance conditions equal to the aircraft maximum weight at takeoff.
 M
Mach number, the ratio between flight speed and speed of sound.
 mML
Aircraft maximum weight at landing.
 mMTO
Aircraft maximum weight at takeoff.
 mPAX
Mass of one passenger including his baggage.
 
The ratio between maximum takeoff weight to wing area, one of the most important values to describe the aircraft.
 nPAX
Number of passengers, the aircraft has to transport.
 OEI
One Engine Inoperative. Critical flight situation that sets performance standards in JAR 25.
 sLFL
Safety landing field length: The required distance to land at the airport. It is determined in JAR 25.
 sTOFL
Safety takeoff field length: The required distance to start at the airport. It is determined in JAR 25.
 sTOG
Takeoff ground roll: The distance at takeoff while the aircraft-gear is on ground.
 SW
Aircraft maximum wing area.
 
  To top of this page
  Back to previous page
 TTO
Thrust of all engines at takeoff.
 V1
Decision speed, aircraft specific speed while takeoff, at which the crew can break off the start for the last time.
According to JAR 25, V1 may not be less than VEF.
 V2
Takeoff speed, according to JAR 25 1.15 or 1.2 times VS, depending on performance of engines and high-lift-systems.
 vAPP
Aircraft speed at landing. According to JAR 25, vAPP has not to be less than 1.3×vS .
 VEF
Engine Failure speed. Speed at which one Engine gets inoperative.
 vLOF
Lift-off speed. Speed at which the aircraft is airborne.
 VS , vS
Stall speed. Minimum speed at which the aircraft is controllable.
 vW
Wind speed at the airport.
Climb gradient, determined in the JAR 25.
Runway slope at the Airport.
Roll friction of the aircraft at runway.
 
The ratio between the density at the airport and the density at sea level (1.225 kg/m³).

 
  To top of this page
  Back to previous page