# SYMBOLS, ABBREVIATIONS AND TERMINOLOGY

CONTENT:

UNIVERSAL SYMBOLS AND ABBREVIATIONS
GENERAL AIRSPEED TERMINOLOGY AND SYMBOLS
METEOROLOGICAL TERMINOLOGY
POWER TERMINOLOGY
ENGINE TERMINOLOGY, CONTROLS AND INSTRUMENTS
AIRPLANE PERFORMANCE AND FLIGHT PLANNING TERMINOLOGY
WEIGHT AND BALANCE TERMINOLOGY

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UNIVERSAL SYMBOLS AND ABBREVIATIONS

A B C D E F G H I J K L M N O P Q R S T U V W X
A | ampère
AC | alternating current
ADF | automatic director finding / finder
ADI | attitude director indicator
AGL | above ground level
ALT | altitude
AM | amplitude modulation
AMPS | ampères
ANT | antenna
ANTI-COLL | anti-collision
AP, A/P | autopilot
approx. | approximate
ARINC | Aeronautic Radio Incorporation, USA
ASA | anti-static additive
ASAP | as soon as possible
ASD | accelerate stop distance
ASI | attitude situation indicator
ASTM | American Society for Testing and Materials
ATC | air traffic control
ATT | attitude
auto | automatic
AVGAS | aviation gasoline
A B C D E F G H I J K L M N O P Q R S T U V W X
bar | 1 bar @ 14.5 psi
BATT / BAT | battery
BFO | beat frequency oscillator
BRG | bearing
BRT | bright
B.S. | British Standard
A B C D E F G H I J K L M N O P Q R S T U V W X
°C | degrees centigrade
CAA | Civil Aviation Agency
CAB | cabin
C/B | circuit breaker
CCW | counter-clockwise
CDI | course deviation indicator
CDU | control display unit
C.G. | center of gravity
COMM | communication
COMB | combustion
CONS | consumption
CONTR | control
COPIL | copilot
CRS | course or cursor
cu ft | cubic foot, cubic feet
CW | clockwise or carrier wave
A B C D E F G H I J K L M N O P Q R S T U V W X
daN | deka (x100) Newton
DC | direct current
DCU | data conversion unit
DEFR | defrost (air)
DG | directional gyro
DH | decision height
D.Eng R.D. | Directorate Engineering Research Development (UK)
DIST | distance
DME | distance measuring equipment
DN, DWN | down
DO | Dornier
DR | dead reckoning
A B C D E F G H I J K L M N O P Q R S T U V W X
E | east
EAROM | electrically alterable read only memory
EGME | ethylene glycol monomethyl ether
ELT | emergency locator transmitter
EMERG/ EMG | emergency
END | endurance
ENG | engine
ESAD | equivalent still air distance
EWC | estimated wind component (- head wind) (+ tail wind)
EXT | external or EXTING (extinguisher)
A B C D E F G H I J K L M N O P Q R S T U V W X
°F | degrees Fahrenheit
FAA | Federal Aviation Agency
FAR | Federal Aviation Regulation
FCU | fuel control unit
FDS | flight director system
FF | fuel flow
FLT | flight
FOD | foreign object damage
ft | foot, feet
ft/min | feet per minute
FRQ | frequency
F.S.I.I. | fuel system icing inhibitor
A B C D E F G H I J K L M N O P Q R S T U V W X
g | acceleration due to gravity
GA | go around or general aviation
GAL | gallon(s)
GEN | generator
GND | ground
GOV | governor
GS | glide slope or ground speed
A B C D E F G H I J K L M N O P Q R S T U V W X
h | hour
HDG | heading
HF | high frequency
HSI | horizontal situation indicator
HTR | heater
Hz | Hertz
A B C D E F G H I J K L M N O P Q R S T U V W X
ICAO | International Civil Aviation Organization
ICS | intercommunication system (intercom)
IFR | instrument flight rules
IGN | ignition
ILS | instrument landing system
IMC | instrument meteorological condition
in | inch, inches
in Hg | inches of Mercury
in lbs | inch pounds
INSTR | instrument(s)
ISA | International Standard Atmosphere
ITT | interturbine temperature, interstage turbine temperature
INVTR | inverter
A B C D E F G H I J K L M N O P Q R S T U V W X
JETT | jettison
A B C D E F G H I J K L M N O P Q R S T U V W X
kg | kilogram (1 kg @ 9.81 N @ 2.207 lbs)
kHz | kilo Hertz
kp | kilopond (1 kp @ 0.981 kg)
kt(s) | knot(s)
kW | kilowatt (1 kW @ 1.341 HP)
A B C D E F G H I J K L M N O P Q R S T U V W X
L | liter
LAND | landing
LBA | Luftfahrt – Bundesamt (German Federal Aviation Agency)
lb(s) | pound(s) (1 lb. @ 0.4536 kg)
LB-FT | foot pound, feet pound (torque)
LCM | list of consumable material
LH | left hand (side)
LOC | localizer
LP | low pressure
LSB | lower side band
LT(S) | light(s)
A B C D E F G H I J K L M N O P Q R S T U V W X
m, M | meter
m², M² | square meter
m³, M³ | cubic meter
mA | milli ampère
MAC | mean aerodynamics cord
MAG/ magn. | magnetic
MAN | manual
max/ MAX | maximum
mb | millibar
MCP | maximum continuous power
MHz | Mega Hertz
mm | millimeter
Mil | military
MIN/ min | minimum
mkg | meterkilogram
MKR | marker
MSG | message
MSL | mean sea level
A B C D E F G H I J K L M N O P Q R S T U V W X
N | Newton or north
NATO | North Atlantic Treaty Organization
NAV | navigation
Ng | gas generator speed
NM | nautical miles
Np | power turbine (propeller) speed
A B C D E F G H I J K L M N O P Q R S T U V W X
OAT | outside air temperature
OBI | Omni bearing indicator
OBS | Omni bearing selector
A B C D E F G H I J K L M N O P Q R S T U V W X
PA/ PAX/ PASS | passenger
PCU | propeller control unit
PIL | pilot
PPH | pounds per hour (lbs/h)
PRESS | pressure
PROP | propeller
psi | pound per square inch (pressure) a = absolute d = differential g = gauged
PTR | pointer
PTT | push to talk
PWR | power
A B C D E F G H I J K L M N O P Q R S T U V W X
QTY | quantity
A B C D E F G H I J K L M N O P Q R S T U V W X
recom | recommended
Ref/ REF | reference
REG | regulator
RELSE | release
RF | radio frequency
RH | right hand (side)
RLY | relay
RNAV | area navigation
RWY | runway
A B C D E F G H I J K L M N O P Q R S T U V W X
SAE | Society of Automotive Engineers
SB | seat belt
sec | seconds
SL | sea level
SPKR | speaker
SR | specific range
STBY | stand by
STOL | short takeoff and landing
SURF | surface
SW.OVR | switch over
SX | selected cross track
A B C D E F G H I J K L M N O P Q R S T U V W X
TAS | true airspeed
TBO | time between overhaul
TEMP | temperature
T.O. | takeoff
T/P | temperature-pressure
TQ | torque
TRANS | transfer
TRCVR | transceiver
T/S | turn and slip
A B C D E F G H I J K L M N O P Q R S T U V W X
USB | upper side band (or computer: Universal Serial Bus)
US GAL (gal) | United States gallons
A B C D E F G H I J K L M N O P Q R S T U V W X
V | speed or volts
VFR | visual flight rules
VG | vertical gyro
VHF | very high frequency
VLF | very low frequency
V/L | vapor liquid
VMTR | voltmeter
VOR | very high frequency omni directional range
VTOL | vertical takeoff and landing
A B C D E F G H I J K L M N O P Q R S T U V W X
WPT | way point
WSHLD | windshield
WX | weather
A B C D E F G H I J K L M N O P Q R S T U V W X
XMTR | transmitter
XPDR | transponder
W | VLF-Omega

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## GENERAL AIRSPEED TERMINOLOGY AND SYMBOLS

CAS | Calibrated Airspeed is the indicated speed of an airplane, corrected for position and instrument error. Calibrated airspeed is equal to true airspeed in standard atmosphere at sea level.
KCAS | Calibrated Airspeed expressed in knots.
GS | Ground Speed is the speed of an airplane relative to the ground.
IAS | Indicated Airspeed is the speed of an airplane as shown on the airspeed indicator when corrected for instrument error. IAS values published in this handbook assume zero instrument error.
KIAS | Indicated Airspeed expressed in knots.
TAS | True Airspeed is the airspeed of an airplane relative to undisturbed air which is the CAS corrected for altitude, temperature, and compressibility.
VA | Maneuvering Speed is the maximum speed at which application of full available aerodynamic control will not overstress the airplane.
VFE | Maximum Flap Extended Speed is the highest speed permissible with wing flaps in a prescribed extended position.
VMC | Minimum Control Speed is the minimum flight speed at which the airplane is controllable with a bank of not more than 5° when critical engine suddenly becomes inoperative and the remaining engine is operating at emergency power and the propeller of the failed engine is windmilling.
VR | Rotation Speed is the speed at which rotation should be initiated to ensure liftoff at takeoff speed.
VSSE | Single Engine Speed is a speed above both VMC and stall speed, selected to provide a margin of lateral and directional control when one engine is suddenly rendered inoperative. For training purposes, intentional failing of one engine in flight at or above this speed is recommended.
VS | Stalling Speed or the minimum steady flight speed at which the airplane is controllable.
VSO | Stalling Speed or the minimum steady flight speed at which the airplane is controllable in the landing configuration (FLAPS 2).
VS1 | Stalling Speed or the minimum steady flight speed obtained in a specific configuration.
Vx | Best Angle-of-Climb Speed is the airspeed which delivers the greatest gain in altitude in the shortest possible horizontal distance.
Vy | Best Rate-of-Climb Speed is the airspeed which delivers the greatest gain in altitude in the shortest possible time.
VMO | Maximum Operating Limit Speed is the speed limit that may not be deliberately exceeded in normal flight operations.
V2 | Takeoff Safety Speed is the minimum speed to be obtained at 50 ft height.

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## METEOROLOGICAL TERMINOLOGY

Altimeter Setting | Barometric Pressure corrected to sea level.
ISA | International Standard Atmosphere in which: (1) The air is a dry perfect gas ; (2) The temperature at sea level is 15° Celsius (59° Fahrenheit) ; (3) The pressure at sea level is 29.92 inches of Mercury (1013.2 millibars) ; (4) The temperature gradient from sea level to the altitude at which the temperature is -56.5°C (-69.7° F) is -0.00198° C (-0.003566° F) per foot (i.e. 36100 ft) and zero above that altitude.
OAT | Outside Air Temperature is the free air static temperature, obtained either from in-flight temperature indications adjusted for instrument error and compressibility effects, or from ground meteorological sources.
Indicated Pressure Altitude | The number actually read from an altimeter when the barometric subscale has been set to 29.92 inches of Mercury (1013.2 millibars). Position errors may be obtained from the Altimeter Correction graph.
Pressure Altitude | Altitude measured from standard sea level pressure (29.92 in. Hg) by a pressure (barometric) altimeter. It is the indicated pressure altitude corrected for position and instrument error. In this handbook altimeter instrument errors are assumed to be zero.
Station Pressure | Actual atmospheric pressure at field elevation.
Wind | The wind velocities plotted as variables on the charts of this handbook are to be understood as the headwind or tailwind components of the reported winds.

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## POWER TERMINOLOGY

Emergency | Highest power rating not limited by time in single engine operation.
Takeoff | Highest power rating not limited by time.
Torque | An indication of power output of the engine.
HP | Horse Power.
SHP | Shaft Horse Power - in turboprop engines the amount of power delivered to the prop, disregarding any surplus thrust generated by the exhaust gases.
RPM | Revolutions Per Minute.
Reverse Thrust | The thrust produced when the propeller blades are rotated past flat pitch into the Beta range.

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## ENGINE TERMINOLOGY, CONTROLS AND INSTRUMENTS

Beta Range | Engine operational mode in which propeller blade pitch is hydro mechanically controlled from the cockpit power Lever.
Igniter | A device (spark plug) used to start the burning of the fuel/air mixture in a combustion chamber.
Impeller | The main rotor of a radial compressor which increase the velocity of the air which it pumps.
Stator | A row of stationary airfoils which direct the airflow between the rows of rotor blades.
Turbine | A rotating device actuated either by reaction or impulse (or a combination of both), and used to transform some of the kinetic energy of the exhaust gases into shaft horse power to drive the compressor(s) and accessories.
Turboprop | A type of gas turbine that converts heat energy into propeller shaft work.
Power Lever | Cockpit Lever used to change propeller pitch during Beta operation and select engine fuel flow during propeller governing.
Condition Lever | Cockpit Lever providing inputs to fuel control.
Interstage Turbine Temperature (ITT) | Gas temperature measured between the compressor and power turbines.
Ng Tachometer (Gas Generator RPM) | The tachometer registers the RPM of the gas generator in %.
Np Tachometer (Propeller RPM) | The tachometer registers the propeller RPM up to a maximum of 1900 RPM.
Torque Meter | The instrument that indicates the torque (turning force) and thus power output of the engine.
Propeller Lever | Cockpit lever used to regulate the RPM of the propeller by increasing or decreasing the propeller pitch through a pitch change mechanism in the propeller hub.

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## AIRPLANE PERFORMANCE AND FLIGHT PLANNING TERMINOLOGY

Climb Gradient | The ratio of the change in height during a portion of a climb, to the horizontal distance traveled in the same time interval.
Demonstrated Crosswind | The maximum 90° crosswind component for which adequate control of the airplane during takeoff and landing was actually demonstrated during certification tests.
Accelerate-Stop Distance | The distance required to accelerate an airplane to a specified speed and assuming failure of an engine at the instant that speed is attained, to bring the airplane to a stop.
Accelerate-Go Distance | The distance required to accelerate an airplane to a specified speed and, assuming failure of an engine at the instant that speed is attained, continue takeoff on the remaining engine to a height of 50 feet.
Landing Distance | The horizontal distance required to land from a 50 ft obstacle height and come to a complete stop.

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## WEIGHT AND BALANCE TERMINOLOGY

Reference Datum | An imaginary vertical plane from which all horizontal distances are measured for balance purposes.
Station | A location along the airplane fuselage usually given in terms of distance from the reference datum.
Arm | The horizontal distance from the reference datum to the center of gravity (C.G.) of an item.
Moment | The product of the weight of an item multiplied by its arm. (Moment divided by a constant is used to simplify balance calculations by reducing the number of digits.)
Airplane Center of Gravity (C.G.) | The point at which an airplane would balance if suspended. Its distance from the reference datum is found by dividing the total moment by the total weight of the airplane.
C.G. Arm | The arm obtained by adding the airplane's individual moments and dividing the sum by the total weight.
C.G. Limits | The extreme center of gravity locations within which the airplane must be operated at a given weight.
Usable Fuel | Fuel available for flight planning.
Unusable Fuel | Fuel remaining after a runout test has been completed in accordance with governmental regulations.
Standard Empty Weight | Weight of a standard airplane including unusable fuel, full operating fluids and full oil.
Empty Weight | This is the Standard Empty Weight plus optional equipment, but not including the removable operational equipment (such as passenger seats in the cabin, stretchers etc.).
Basic Weight | Standard Weight plus optional equipment and modifications.
Payload | Weight of occupants, cargo, and baggage.
Useful Load | Difference between takeoff weight and empty weight.
Maximum Ramp Weight | Maximum weight for ground maneuver including fuel weight for start-up engines and taxi.
Maximum Takeoff Weight | Maximum weight approved for the start of the takeoff run.
Maximum Landing Weight | Maximum weight approved for the landing.
Maximum Zero Fuel Weight | Maximum weight exclusive of usable fuel.

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Taken from the Pilot's Operating Handbook (Revision 10 of 1 November 1983) of the Dornier 128-6 registered as "D-IBUF" and currently owned and flown by the Institute of Flight Guidance and Control of the University of Braunschweig, Germany.

Set into html format by Mathias Elsaesser in June 2001.