RePL key terms

A licence issued by CASA that allows a person to act as remote pilot of an RPA for commercial or other non-recreational purposes. It is obtained by passing theory, practical and flight assessments.

An aircraft flown by a remote pilot from a control station with no pilot on board. Australian rules use this term for drones flown commercially or for work, as distinct from model aircraft flown only for sport.

A certificate issued by CASA to a business or organisation permitting it to conduct commercial drone operations. The organisation must hold the certificate and engage at least one person who holds a Remote Pilot Licence.

A drone that falls outside the registration and operator accreditation requirements of CASR Part 101, such as very small aircraft and those flown purely for sport or recreation.

The part of the Civil Aviation Safety Regulations that sets out the rules for operating unmanned aircraft in Australia, including licensing, registration, operating limits and approval requirements.

The default conditions in CASR Part 101 that let operators fly commercially without a ReOC, including daylight only, within visual line of sight, below 120 metres and away from people and aerodromes.

The requirement that the remote pilot can see the aircraft directly, without relying only on a camera view or binoculars, and can watch its flight path and the surrounding airspace at all times.

The requirement not to fly an RPA closer than 30 metres horizontally to any person who is not part of the operation, so that bystanders are not put at risk of injury.

The maximum height of 120 metres (about 400 feet) above ground level at which an RPA may be flown under standard operating conditions without a specific approval.

An area where people are gathered or living closely enough that a drone failing in flight could injure someone, such as a beach, park, crowd or built-up suburb. Flying over such areas is restricted.

A rule that prevents RPA operations within 5.5 km of a controlled aerodrome unless an approval has been obtained, keeping drones clear of manned aircraft arriving and departing.

The angle between the wing's chord line and the relative airflow. Increasing it increases lift up to a point, beyond which the wing stalls and lift drops sharply.

The sudden loss of lift when a wing exceeds its critical angle of attack. It results from too much angle or too little airspeed and can occur at any height or attitude.

Pressure altitude corrected for temperature. High temperature or high elevation reduces air density, which lowers lift and propeller thrust and reduces climb performance and endurance.

The point through which the aircraft's total weight is considered to act. Loading payload so the CG falls outside the approved range makes the aircraft unstable or difficult to control.

Adding cameras, sensors or extra batteries increases weight and drag, raising power demand and shortening flight time. Pilots must plan the flight around the reduced endurance this causes.

A routine aviation weather report issued for an aerodrome, stating wind, visibility, cloud, temperature, dew point and pressure at a nominated time.

Aerodrome forecast: a statement of the weather expected at an aerodrome over a set period, covering wind, visibility, cloud and any significant expected changes.

The altimeter setting that makes the instrument read elevation above mean sea level at the aerodrome. It links reported heights to terrain and to airspace limits.

A rapid change in wind speed or direction over a short distance or time. It can suddenly alter a drone's ground speed, height and controllability, particularly near buildings and in gusty conditions.

A notice to airmen: a short-notice warning of temporary changes or hazards in the airspace or at an aerodrome, such as closures, works or temporary restricted areas, checked before flight.

The Aeronautical Information Package, the official Australian publication containing regulations, airspace descriptions, charts and aerodrome data used for flight planning.

En Route Supplement Australia: a directory of aerodrome and facility information including frequencies, runways, lighting and local procedures, published as part of the AIP.

Uncontrolled airspace in which no air traffic control clearance is required. Most drone flying happens here, and the pilot must still see and avoid other aircraft.

Airspace marked on charts where flight is limited or prohibited without permission, for example around prisons, military bases, fire zones or major events.

The angular difference between true north and magnetic north at a particular location. It must be applied when converting a bearing taken from a chart to a heading.

The pilot's accurate understanding of the aircraft, its surroundings and what is likely to happen next. Losing it is a common precursor to an accident.

A state of physical and mental tiredness that slows reactions and weakens judgement. It builds with long days, early starts and repeated flights, and must be managed before it affects safety.

A structured approach to spotting threats, avoiding errors and trapping them before they cause harm, then reviewing what happened and why.

An organisation's formal system for managing risk, covering hazard identification, risk assessment, reporting, training and continuous improvement of safety performance.

The radiotelephony distress signal, spoken three times, used when an aircraft or person is in grave and imminent danger and immediate assistance is required.

The radiotelephony urgency signal, spoken three times, used for a serious situation that is not yet an immediate danger to life, such as low battery or lost navigation.

The standard words such as Alpha, Bravo and Charlie used to spell out letters clearly over the radio so that similar-sounding letters are not confused.

Common Traffic Advisory Frequency: a frequency used at non-controlled aerodromes where pilots broadcast their position and intentions so others know where they are and what they plan.

An automated function that flies the aircraft back to its launch point, either when commanded or after a link or battery failure. Its height and path must be set to clear obstacles.

The pre-planned action taken when control or video link is lost, usually automatic return to home or hovering, together with what the pilot will do if the link does not recover.

A documented check of the operating site before flight that identifies hazards such as people, powerlines, trees and other aircraft, and lists the controls that reduce each risk.

The battery type commonly used in drones. It must be stored and charged correctly, checked for swelling or damage and never flown below safe voltage, because it can catch fire.

The final judgement before flight that planning, weather, aircraft, crew and site conditions are all acceptable. If any limit is exceeded, the flight does not proceed.