SYMBOLS, ABBREVIATIONS AND TERMINOLOGY
 

GENERAL AIRSPEED TERMINOLOGY AND SYMBOLS

KCAS Knots Calibrated Airspeed is indicated airspeed corrected for position and instrument error and expressed in knots. Knots calibrated airspeed is equal to KTAS in standard atmosphere at sea level.

KIAS Knots Indicated Airspeed is the speed shown on the airspeed indicator and expressed in knots.
 

KTAS Knots True Airspeed is the airspeed expressed in knots relative to undisturbed air which is KOAS corrected for altitude and temperature.

V_A Manuevering Speed is the maximum speed at which you may use abrupt control travel.

V_FE Maximum Flap Extended Speed is the highest speed permissible with wing flaps in a prescribed extended position.

V_LE Maximum Landing Gear Extended Speed is the maximum speed at which an airplane can be safely flown with the landing gear extended.

V_LO Maximum Landing Gear Operating Speed is the maximum speed at which the landing gear can be safely extended or retracted.

V_NO Maximum Structural Cruising Speed is the speed that should not be exceeded except in smooth air, then only with caution.

V_NE Never Exceed Speed is the speed limit that may not be exceeded at any time.

V_S Stalling Speed or the minimum steady flight speed at which the airplane is controllable.

V_So Stalling Speed or the minimum steady flight speed at So which the airplane is controllable in the landing configu ration at the most forward center of gravity.

V_X  Best Angle-at-Climb Speed is the speed which results in the greatest gain of altitude in a given horizontal distance.

V_Y  Best Rate-of-Climb Speed is the speed which results in the Y gr6atest gain in altitude in a given time.
 

METEOROLOGICAL TERMINOLOGY

OAT Outside Air Temperature is the free air static temperature. It is expressed in either degrees Celsius or degrees Fahrenheit.

Standard Temperature is 15 C at sea level pressure altitude and decreases by 2⁰C for each 1000 feet of altitude. ture

Pressure Altitude is the altitude read from an altimeter when the altimeter's barometric scale has been set to 29.92 inches of mercury (1013 mb).
 

ENGINE POWER TERMINOLOGY

BHP Brake Horsepower is the power developed by the engine. RPM Revolutions Per Minute is engine speed.

MP Manifold Pressure is a pressure measured in the engine's induction system and is expressed in inches of mercury (Hg).
 

AIRPLANE PERFORMANCE AND FLIGHT PLANNING TERMINOLOGY

Demonstrated Crosswind Velocity is the velocity of the crosswind component for which adequate control of the airplane during takeoff and landing was actually demonstrated during certification tests. The value shown is not considered to be limiting.

Usable Fuel is the fuel available for flight planning.

Unusable Fuel is the quantity of fuel that can not be safely Fuel used in flight.

GPH Gallons Per Hour is the amount of fuel (in gallons) consumed per hour.

NMPG Nautical Miles Per Gallon is the distance (in nautical miles) which can be expected per gallon of fuel consumed at a specific engine power setting and/or flight configuration.

g is acceleration due to gravity.
 

WEIGHT AND BALANCE TERMINOLOGY

Reference Datum is an imaginary vertical plane from Datum which all horizontal distances are measured for balance purposes.

Station is a location along the airplane fuselage given in terms of the distance from the reference datum.

Arm is the horizontal distance from the reference datum to the center of gravity (0.0) of an item.

Moment is the product of the weight of an item multiplied by its arm. (Moment divided by the constant 1000 is used in this handbook to simplify balance calculations by reduc ing the number of digits.)

Center of Gravity (CG) is the point at which an airplane, or equipment, would balance if suspended. Its distance from the reference datum is found by dividing the total moment by the total weight of the airplane.

Center of Gravity Arm is the arm obtained by adding the Arm airplane's individual moments and dividing the sum by the total weight.

Center of Gravity Limits are the extreme center of gravity Limits locations within which the airplane must be operated at a given weight.

Standard Empty Weight is the weight of a standard airplane, including unusable fuel, full operating fluids and full engine oil.

Basic Empty Weight is the standard empty weight plus the Weight weight of optional equipment.

Useful Load is the difference between ramp weight and the basic empty weight.

 Maximum Ramp Weight is the maximum weight approved for ground maneuver. (It includes the weight of start, taxi and runup fuel.)

Maximum Takeoff Weight is the maximum weight approved for the start of the takeoff run.

Maximum Landing Weight is the maximum weight approved for the landing touchdown.

Tare is the weight of chocks, blocks, stands, etc. used when weighing an airplane,  and is included in the scale readings. Tare is deducted from the scale reading to obtain the actual (net) airplane weight.