RPAS Basic key terms

The requirement that the remote pilot keep the aircraft in direct unaided sight at all times, without binoculars or screens, so its position and attitude can be judged and conflicts avoided.

Operations in which the aircraft flies outside the pilot's direct unaided view, requiring alternative means such as observers, sensors, or approved procedures to maintain separation from other traffic.

The equipment and location from which the remote pilot controls the aircraft, including the control unit, displays, and any telemetry links needed to monitor and command the flight.

The radio data connection carrying control inputs from the pilot station to the aircraft and returning status information, whose reliability and range govern how far the aircraft can safely operate.

A pre-programmed set of actions the aircraft performs automatically when the command and control link fails, such as holding, returning to a set point, or landing, designed to keep people and property safe.

A design feature or programmed behaviour that brings the aircraft to a safe state when a system fails, for example automatic return to home on loss of signal or low battery.

A software-defined boundary, set by coordinates or database, that limits where the aircraft may fly and can trigger warnings, flight restriction, or automatic stopping at the boundary.

An area where aircraft operations are prohibited or restricted by the competent authority, such as around airports, prisons, or sensitive installations, which the remote pilot must identify before flight.

The system of lettered classes (A to G) that sets the rules for who may fly where, what clearances are needed, and what separation is provided, determining whether a drone may enter a given volume.

Airspace of defined dimensions in which air traffic control service is provided and entry generally requires an authorisation, so a remote pilot needs clearance or an exemption before flying there.

An authorisation from air traffic control for an aircraft to proceed under specified conditions, which must be requested and complied with when operating in controlled airspace.

The standard phraseology and procedures used for voice communication with air traffic services, including callsigns, read-backs, and distress language, required where a radio is mandated.

An airborne device that replies to radar interrogations with an identity code and, in mode S or C, altitude, helping air traffic control and other aircraft detect and identify the drone.

The capability to see, sense, or otherwise become aware of conflicting traffic or obstacles and to take timely action to avoid them, whether by the pilot's senses or by onboard systems.

The rule determining which aircraft must give way in a potential conflict, for example that the less manoeuvrable or lower aircraft normally has priority and others must pass well clear.

Any aircraft flown by a pilot on board, which remote pilots must avoid and normally give way to, since the crew usually cannot see small drones until very close.

The principle that pilots must actively scan for other traffic and take action to avoid collisions, applied to remote pilots through direct visual observation or approved替代 means.

The greatest mass at which the aircraft is certified to begin a flight, including payload, battery, and any fitted equipment, and a key figure for regulatory category and performance limits.

Everything the aircraft carries that is not required for flight, such as cameras, sensors, or dispensable loads, whose mass and position affect performance and balance.

The point at which the aircraft's weight is considered to act; it must stay within a permitted range or control and stability degrade, especially after adding or shifting payload.

The tendency of an aircraft to return to its trimmed flight condition after a disturbance, affected by design, loading, and centre of gravity position.

The ability of the aircraft's control surfaces or motor outputs to produce the forces needed to change attitude, which depends on airspeed, thrust margin, and remaining battery power.

A rotorcraft with several powered rotors, typically three to eight, that controls attitude by varying individual rotor speeds, offering vertical take-off but limited endurance compared with fixed-wing types.

A drone that derives lift mainly from wings moving through the air rather than from rotors, giving longer range and endurance but requiring forward speed and usually a launch and recovery method.

The loss of lift that occurs when the wing exceeds its critical angle of attack, causing a sudden sink or drop that a fixed-wing drone recovers from by reducing angle of attack and adding speed.

The angle between the wing chord and the oncoming airflow; increasing it raises lift up to a critical value, beyond which the wing stalls.

The aerodynamic force acting perpendicular to the flight path that supports the aircraft in the air, produced by airflow over wings or rotors and increasing with airspeed and angle of attack.

The device that regulates power from the battery to an electric motor in response to commands, converting throttle or attitude demands into the precise motor speeds needed for control.

A rechargeable battery type common in drones, offering high energy for its weight but requiring care because over-discharge, damage, or heat can cause swelling, fire, or sudden loss of power.

The usable flight time available from the installed energy source, which shrinks in cold, wind, or high-payload conditions and must be planned with a reserve for diversion and landing.

The margin of energy or fuel that must remain at planned landing to cover unexpected delays or diversion, a planning requirement that applies equally to battery and liquid-fuel drones.

The pre-flight process of checking weather, airspace, NOTAMs, site hazards, performance, and energy needs, and deciding the route and contingencies before take-off.

A notice distributed to airspace users about temporary changes or hazards such as closed areas, works, or special events, which a remote pilot should check before flying.

A structured review of what could go wrong on a flight, how likely and severe each hazard is, and what controls will reduce the risk to an acceptable level before launch.

The pilot's up-to-date understanding of the aircraft, the surrounding traffic, the environment, and the state of the operation, which allows early recognition of developing problems.

The mental and physical effort demanded by the task at a given moment; when it exceeds the pilot's capacity, errors increase, so tasks should be planned and shared where possible.

A relaxed state of overconfidence after many routine flights, in which checks are skipped and warnings ignored, making it a common contributor to avoidable accidents.

A written list of actions performed in a fixed order before, during, and after flight to ensure critical items are not missed, reducing reliance on memory under pressure.

A sudden change in wind speed or direction over a short distance, often near buildings, trees, or fronts, which can cause abrupt altitude loss or loss of control at low level.

Irregular, gusty air motion caused by terrain, buildings, convection, or other aircraft, which disturbs small drones strongly and can exceed their control authority near the ground.

The altitude the air would have under standard conditions for its actual density; hot, high, or humid conditions raise it and reduce lift and motor performance.

Vertical air motion driven by surface heating, producing thermals, cumulus cloud, gusty surface wind, and sometimes thunderstorms that are hazardous to light drones.

The greatest distance at which prominent objects can be seen and identified, a limiting factor for keeping the drone in sight and for judging its attitude and surroundings.

The height of the lowest cloud layer reported as broken or overcast, or the vertical visibility into obscuration, used to judge whether cloud will interfere with the flight.