Abbreviations and Terminology

Definitions for common terminology

Meteorological Terminology

Term

Definition

ISA

International Standard Atmosphere in which:

The air is a dry, perfect gas;

The temperature at sea level is 15° Celsius (59° Fahrenheit);

The pressure at sea level is 1013.2 mbar (29.92 inches Hg);

The temperature gradient from sea level to the altitude at which the temperature is -56.5°C (-69.7°F) is -0.00198°C (-0.003564°F) per foot and zero above that altitude

MSL

Mean Sea Level is the average height above the surface of the sea for all stages of tide

AGL

Above Ground Level is the height of the aircraft above the ground

OAT

Outside Air Temperature is the free air static temperature surrounding the aircraft

Pressure Altitude

Altitude measured from standard sea level pressure (1013.2 mbar, 29.92 in. Hg) by a pressure or barometric altimeter

It is the indicated pressure altitude corrected for position and instrument error. In this Manual, altimeter instrument errors are assumed to be zero

Power Terminology

Term

Definition

Maximum Continuous Power Output

The maximum typical power output of a motor averaged over the entire flight

Maximum Instantaneous Peak Power Output

The maximum power output of a motor during any phase of flight, such as when maneuvering

Flight and Powerplant Control

Term

Definition

Throttle Stick

The radio controller stick responsible for throttle control. For Mode 2 controllers, this is the vertical movement of the left control stick. For Mode 1 controllers, this is the vertical movement of the right control stick

Yaw Stick

The radio controller stick responsible for yaw (also called pan) control

For Mode 2 and Mode 1 controllers, this is the lateral movement of the left control stick

Pitch Stick

The radio controller stick responsible for pitch control. For Mode 2 controllers, this is the vertical movement of the right stick

For Mode 1 controllers, this is the vertical movement of the left stick

Roll Stick

The radio controller stick responsible for roll control. For Mode 2 and Mode 1 controllers, this is the lateral movement of the right control stick

Pitch/Roll Stick or Cyclic Stick

The radio control stick responsible for both pitch and roll control

For Mode 2 controllers, this is the right stick

Weight and Balance

Term

Definition

Maximum Takeoff Weight (MTOW)

Maximum allowable weight at liftoff

Standard Empty Weight

Weight of a standard aircraft

Basic Empty Weight

Standard empty weight plus optional equipment

Useful Load

Difference between take off weight and basic empty weight

Payload

Useful load less battery weight

General Terminology

Term

Definition

LOS

Loss of Signal

RTH

Return-to-Land

sUAS

Small Unmanned Aircraft System includes all components of the system required for the flight of an unmanned aircraft, including the radio controller, data link and other related support equipment