The terms; ‘Unmanned Aerial Vehicle’ (UAV); ‘Unmanned Aircraft System’ (UAS); ‘Remotely Piloted Aircraft System’ (RPAS); and ‘Drone’ are, in the broad, all references to one and the same thing, this being:
“An aircraft [or aircraft-system] that is flown from a remote location without a pilot located in the aircraft itself.”
Normally the operator of such an aircraft is located on the ground, but they could also be stationed in a vehicle, a boat or even another (manned) aircraft.
‘UAV’ was the original term adopted by CASA in July 2002 and is still widely in use including much of CASA certification, licencing and guidance material. This term predominated at the time of the formation of the Australian Certified UAV Operators and its legal incorporation.
‘UAS’ is the more up-to-date internationally accepted term in use today, with this now recognised as the overarching ‘class’ terminology by ICAO as well as by CASA.
‘RPAS’ is defined by ICAO as a form of UAS which is non-autonomous in its capacities, the aircraft being subject to direct pilot control at all stages of flight despite operating ‘remotely’ from that pilot. CASA has recently shifted to use of the term RPAS as its primary day to day terminology.
The CASA reference material makes reference throughout to UAVs, UAS and RPAS, with respective application dependent upon the phase of discussion in question. Background discussion of ACUO for example, will refer to UAV, UAS & RPAS, given the historical origins of the association.
‘Drone’ historically refers to a UAS which exists to act as a target for live-fire air defence weapons training by armed forces, with this remaining the correct terminological reference. Popular culture, particularly the media, uses the term as a generic descriptor for all classes of unmanned or remotely piloted aircraft, but particularly in relation to military systems with weapons carriage capabilities.
Recreational ‘remotely piloted’ aircraft are considered by CASA as ‘Model Aircraft’, and are flown only for sport & recreation purposes under the administration of the Model Aeronautical Association of Australia (MAAA) and the Civil Aviation Safety Regulations (CASR) 1998 - Part 101.G.
ACUO notes that the UAS sector as a whole is continuing to undergo significant technological advancement, with this driving much of the ongoing revision of terminologies and definitions. This is not unusual in a new industry and mirrors terminological and definitional flux as seen in the rise of commercial aviation and the motor transport industry in the early 20th century. Notwithstanding, the ongoing work of ICAO with respect to standardising terminology and definitions can be expected to result in a ‘lock in’ within short years, with the terms UAS and RPAS already holding legal status in a number of jurisdictions.