Remotely piloted aircraft are one type of unmanned aircraft. All unmanned aircraft, whether remotely piloted, fully autonomous, or a combination thereof, are subject to the provisions of Article 8 titled Pilotless Aircraft of the Convention on International Civil Aviation.
Any aircraft intended to be flown without a pilot on board is referred to in the Convention on International Civil Aviation (Doc 7300), signed at Chicago on 7 December 1944 and amended by the ICAO Assembly as a “pilotless aircraft”.
Today we call these aircraft “unmanned” rather than “pilotless”. Unmanned aircraft (UA) includes a broad spectrum from meteorological balloons that fly freely to highly complex aircraft piloted from remote locations by licensed aviation professionals.
The latter are part of the category referred to as “remotely piloted aircraft” or RPA that operate as part of a system, a remotely piloted aircraft system (RPAS).
RPAS are creating a new industry with large economic potential. They offer a vast range of capabilities and sophistication. Their associated technologies, designs, and operating concepts are evolving rapidly. It is within this context that States are being challenged with the safe and efficient integration of RPAS into environments shared by a highly regulated and well-established manned aircraft industry.
As stated above, RPA operates as part of a system called an RPAS. When discussing RPAS or their operations, it is essential to clarify when the entire system (RPA + Remote Pilot Station (RPS) + Command and Control (C2) link + other) is the focus or a portion of the system is the subject, e.g. the RPAS operator conducts RPAS operations, however, RPA are separated from other aircraft in the airspace.
The operation of RPAS has been identified as having the potential for significant economic, societal, and environmental benefits and the rapid growth of RPAS has caused an increasing demand for them to operate beyond visual line-of-sight (BVLOS) and in airspace open to other aircraft. While such operations are currently allowed, each case must be separately assessed from a safety risk management perspective. There is a need to establish the principles for RPAS operations in all classes of non-segregated airspace.
RPAS operations are currently structured around two major concepts: VLOS and beyond visual line-of-sight (BVLOS), which generally are being developed in areas not currently served by manned aircraft, e.g. the lower or higher altitude environments and extreme endurance.
Operations that are conducted outside of VLOS are considered as “beyond VLOS” and where these can be flown in international airspace under IFR.
As experience is gained and technical capability grows, RPAS will undoubtedly transition into all areas of the airspace, as well as provide new solutions that will be adopted by manned aviation. It is clear that there will be continued innovation and with this a reasonable expectation to be able to access the airspace in a manner that will allow safe, seamless, and efficient end-to-end operations for all aircraft operations.
The key assumptions, which can be considered to apply to all RPAS operations, are described as follows:
- Access to the airspace remains available to all, providing each RPA is capable of meeting pertinent conditions, regulations, processes and equipage defined for that airspace;
- New types of operations may need additional or alternative considerations, conditions, regulations, processes and operating procedures; the objective should be to add only the minimum necessary to achieve safe operation;
- The RPA has the functional capability to meet the established normal and contingency operating procedures for the class of airspace, aerodrome, etc., when such procedures are available;
- The flight operation does not impede or impair other airspace users, service providers (such as air traffic management (ATM), aerodromes etc.) or the safety of third parties on the ground and their property, etc.;
- The RPA must operate in accordance with Annex 2 – Rules of the Air;
- The RPAS must meet the applicable certification/registration/approval requirements;
- The operator must meet the applicable certification/approval requirements; and
- The remote pilot must be competent, licensed and capable of discharging the responsibility for safe flight.
RPAS System Overview
RPAS are a subset of UAS. The term UAS encompasses all aircraft flown without a pilot on board that operates as part of a larger system. This includes RPAS, autonomous aircraft, and model aircraft. Autonomous aircraft differ from RPAS in that they do not permit the intervention of a human pilot to fulfill their intended flight; whereas model aircraft are distinguished by their recreational use. In some instances, the three subcategories of UAS overlap.
An RPAS consists of a remotely piloted aircraft (RPA), remote pilot station (RPS), command and control (C2) link, and any other components as specified in the type design. These components must be approved as a system taking into account the interdependencies of the components. The RPAS must also be interoperable with the ATC and airspace user systems. This section provides further descriptions of the potential RPAS component designs that require approval and oversight.
Remotely Piloted Aircraft (RPA)
There is a wide array of types of RPA. Many mimic the designs and flight characteristics of conventional aircraft. This is particularly true where RPA may be used in traditional manned operations, such as large commercial cargo transport. Whereas other RPA designs are dramatically different.
The opportunities in design, because the pilot is no longer situated within the aircraft, meaning that novel architectures are possible. Unique applications of airframes, powerplants, fuels, and materials can result in flight characteristics different from conventional aircraft, most notably extreme flight endurances, very high altitudes, and slow flight.
There are a number of potential elements of RPA that, while essential for safe operation, are no longer considered as permanent features of the aircraft. For example, launch and recovery systems that replace typical landing gear, wheels, and brakes. These systems are considered to be part of the aircraft system (i.e. RPAS) in so far as they are required for safe flight.
Remote Pilot Station (RPS)
The RPS consists of the equipment used to command, control, and monitor the flight of the RPA. Designs can range from simple hand-held devices to complex, networked, multi-console configurations. The RPS may be located inside or outside of a building and maybe stationary or mobile (installed in a vehicle/ship/aircraft). Security, both physical and cyber, must be assured. An RPA will only be controlled from one RPS at a time.
For international operations – especially those involving very long duration flights – multiple, distributed RPS may be employed. These RPS may be located at different aerodromes, or at off-aerodrome locations, even in different States, as determined by the operator’s infrastructure or need for communications coverage.
The command and control (C2) link is the data link between the remotely piloted aircraft and the remote pilot station for the purpose of managing flight. There are a variety of possible architectures and considerations in the design, security, and management of the C2 Link.
Radio line-of-sight and beyond radio line-of-sight (RLOS & BRLOS)
The C2 Link can be maintained within radio line-of-sight (RLOS) or beyond radio line-of-sight (BRLOS).
RLOS: refers to the situation in which the transmitter(s) and receiver(s) are within mutual radio link coverage and thus able to communicate directly or through a terrestrial network, provided that the remote transmitter has RLOS to the RPA and transmissions are completed in a comparable timeframe.
BRLOS: refers to any configuration in which the transmitters and receivers are not in RLOS. BRLOS thus includes all satellite systems and possibly any system where an RPS communicates with one or more ground stations via a terrestrial network that cannot complete transmissions in a timeframe comparable to that of an RLOS system.
In order to facilitate international operations, the technical and performance requirements of both the RLOS and BRLOS C2 Links will need to be defined and agreed upon internationally.
RPAS operating internationally must comply with the framework regulations and requirements defined under the Convention on International Civil Aviation. At the highest level, this means the:
- RPAS operator must have obtained special authorization from all affected States;
- RPA must be so controlled as to obviate danger to civil aircraft;
- RPAS operators must hold an RPAS operator certificate;
- RPA must hold a valid certificate of airworthiness, issued against the approved type design (as recorded in the type certificate);
- RPA must meet the communications, navigations and surveillance (CNS) requirements for the airspace in which it flies;
- Flight crew (remote pilot(s)) must hold valid licenses appropriate to the RPA and RPS;
- The flight plan must comply with the conditions in Annex 2 – Rules of the Air, Chapter 3, 3.3; and
- RPAS must meet the DAA capability requirements for the airspace in which it flies and the operations to be performed.
RPAS operators are defined as any individual, organization, or enterprise engaged in RPAS operations. “RPAS operators” encompasses all commercial and private entities regardless of whether their RPA are flown for air transport, general aviation, or aerial work purposes.
All operators that undertake operations in international airspace must hold an RPAS operator certificate and must comply with the requirements of the operational approval issued by the State of the Operator, including safety management system requirements.
Operators of RPAS will be responsible for ensuring:
- Airworthiness of the RPA;
- C2 Link services used during an operation meet appropriate performance requirements;
- Flight crew members required for safety of flight are qualified and competent in their duties;
- Arrangements with contractual entities (e.g. service providers) involved in the conduct of flight operations are appropriate;
- Required records are established, managed and stored appropriately;
- Compliance with all requirements established by the State of the Operator regarding its operation; and
- Compliance with all international standards and ATM instructions.
The RPAS operator should establish procedures to ensure a seamless operation throughout the duration of the flight, including remote pilots who can carry out the responsibilities for the different phases of the flight, such as take-off, climb, cruise, approach, and landing, all of which should be included in the operations manual and which should be provided for the use and guidance of the RPAS operations personnel concerned. RPA will need to adhere to air traffic flow management (ATFM) initiatives, make all necessary reports to ATC, and comply with ATC instructions, as required.
Understanding the risks of these future operations as well as the foreseeable introduction of new technologies and operations make adherence to sound safety management principles more important than ever. Therefore, the implementation of safety management principles by RPAS operators will contribute to the ability of assessing the safety risks associated with the RPAS operations and their potential impact on other service providers. The safety management system of an RPAS operator should be commensurate with the scope of the RPAS operator and the scale and complexity of its operations. Proper oversight of the implementation of safety management principles by RPAS operators will contribute to the ability of a State to effectively manage aviation safety.