Newsletter Autumn 2017 – Some Issues regarding Drones (Remotely Piloted Aircraft Systems)


Some Issues regarding Drones (Remotely Piloted Aircraft Systems)


Drones are today tools, which are becoming more and more common.

The threat faced by military drones to civil aircraft is ominous. One will also consider that those responsible for operating RPAS such as the remotely-piloted Predator MQ-1 or Reaper MQ-9 aircraft do not usually seek or receive the permission as prescribed by Article 3(c) of the ICAO manual. One will be aware that an RPAS like this carries sophisticated weapons, and is programmed to launch lethally accurate strikes against terrorists in conflict areas of the world. One should also consider that an RPAS, such as for instance the Reaper, does not have a pilot in the cockpit, but more than 180 people are require to keep the drone flying. A pilot is however always at the controls, and another officer operates its sensors and camera.

The ICAO RPAS Manual recognizes a State in which hazards and risks to safety are reduced and alludes to safety management systems as systematic approaches to managing safety, including the necessary organizational structures infrastructure, formalities and procedures.

It is clear that there are many safety aspects in aviation.

The Manual on Remotely Piloted Piloted Aircraft Systems of ICAO refers to article 8 of the Chicago Convention, requires special authorization by the State flown over by an aircraft capable of being flown without a pilot, which is in fact flown without a pilot. One can say that an aircraft which is flown without a pilot in command on board the aircraft but which is either remotely or fully controlled from another place in the aircraft.

Pilotless aircraft

The released manual by ICAO is the Unmanned Aircraft System manual 328-AN/190.

An aircraft operating without a pilot on board present a wide array of hazards to the civil aviation system. One can identify those hazards and safety risks management, just as with the introduction of an airspace redesign, new equipment or procedures.

The states will have to and are require to establish a State Security Programme (SSP) to include safety rulemaking, policy development and oversight. Needless to say that operation of RPAS in desegregated airspace would not only affect operation carried by commercial air carriers but would also affect general aviation. Some organisation such as IAOPA commented in this respect operating rules for RPAS must take into account their potential impact on general aviation aircraft operating in un-segregated airspace. It was also added that while segregated airspace contains operations subject to air traffic control, un-segregated airspace depends almost entirely on certain Annex 2 to the Chicago Convention cruising altitude conventions and mutual self-separation methods.

The second point raised by IAOPA is that state or military RPAS must abide by whatever RPAS operating rules are devised to ensure safe, hazard-free operations. Because non-civil RPAS operations may wish to use lower altitude un-segregated airspace, there could be a tendency for States and the military to pre-empt conventional flight rules in these areas, either on a temporary or permanent basis.

Compliance with ICAO standards

One refers to the point that on the two questions raised by IAOPA seemingly rests with the fact that RPAS will operate in accordance with ICAO standards that exist for manned aircraft as well as any special and specific standards that address the operational, legal and safety differences between manned and unmanned aircraft operations. Such will include applicable environmental rules and guideless as well. The pilot will be responsible for RPAS to integrate into non-segregated airspace and at non-segregated aerodromes.

Collision Avoidance

An aircraft is an craft piloted by a licensed ‘remote pilot’ situated at a ‘remote pilot station’ located external to the aircraft (ground, ship, another aircraft space, who monitors the aircraft at all times and can respond to instructions issued by ATC, communicates via voice or data link as appropriate to the airspace or operation, and has direct responsibility for the safe conduct of the aircraft throughout its flight.

The fundamental principle is that the pilot in command of an RPAS is as responsible as a pilot of a manned aircraft for detecting and avoiding potential collisions and other hazards. Needless to say that there will be technology provided by which the remote pilot will have sufficient knowledge of the aircraft’s environment to fulfil the responsibility.

Remote pilots will also be subject to the same requirements as aircraft pilots who are required to observe, interpret and heed a diverse range of visual signals intended to attract their attention and/or convey information.

Air Traffic Management

Needless to say that air traffic services should be applicable the greatest practicable extent and the introduction of RPAS must nog increase the risk to other aircraft or third parties and should not prevent or restrict access to airspace. ATM procedures for handling RPAS should mirror those for manned aircraft whenever possible. There will be some situations and/or instances where the remote pilot cannot respond in the same manner as could an on-board pilot and the manual calls for ATM procedures to be able to take account of these difference. For this purpose , ATS remote pilot communication requirements must be assessed in the context of an ATM function, taking into account human interactions, procedures and environmental characteristics. There will also be a safety management system.

The Chicago Convention and more especially annex 11, which deals with the subject of ATS, lays down requirements for coordination of activities that are potentially hazardous to civil aircraft. The international SARPs in the Annexe, Chapter 1, (2.17 and 2.18 in particular) provisions for coordination between military authorities and ATS and coordination of activities potentially hazardous to civil aircraft.

Without going into detail it is good to know that Standard 2.17.1 stipulates that arrangements for activities potentially hazardous to civil aircraft, whether over the territory of a state or over high seas, shall be coordinated with the appropriate ATS authorities. These kind of coordination should be effected early enough to permit timely promulgation of information regarding the activities in accordance with the provisions of Annexe 15 to the Chicago Convention. Standard 2.17.2 of Annex 11 explains that the objective of the coordination referred to in the earlier provision shall be to achieve the best arrangements that are calculated to avoid hazards to civil aircraft and minimize interference with the normal operations of aircraft.

One will also consider Article 89 of the Chicago Convention which stipulates that in case of war, the provisions of the Conventions and its annexes shall not affect the freedom of action of any ICAO’s Member States affected, whether as belligerents or as neutrals.

Flights over the high seas

Whether a military RPAS or a civilian RPAS operates air services across borders, the three fundamental provisions that will guide them are Articles 3(c), 8 and 9 as for flights over the high seas, Article 12 of the Chicago Convention governs fundamental principles.

Article 12 obligates each contracting state to adopt measures to insure that every aircraft flying over or manoeuvring within its territory and that every aircraft carrying its nationality mark, wherever such aircraft may be, will comply with the rules and regulations relating to the flight and manoeuvre of aircraft there in force. Art. 12 also obligates each contracting state to keep its own regulations in these respects uniform, to the greatest possible extent, with those established from time to time under the Chicago Convention. Over the high seas, the rules in force are those established under the Convention. Furthermore, each contracting State undertakes to insure the prosecution of all persons violating the regulations applicable.

Annex 2 to the Chicago Convention states the rules of the air shall apply to aircraft bearing the nationality and registration marks of a contracting state. These rules are applicable to RPAS as well. As one will notice two main categories of rules of the air exist: visual flights rules and instrument flight rules. One shall also consider the note to Article 2.2 of annex 2, which states inter alia that a pilot may elect to fly in accordance with instrument flight rules in visual meteorological conditions. The rules of the air adhered to are thus distinct and separate from the metrological conditions prevailing in the area of operation, except for instrument metrological conditions, requiring instrument flight rules to be applied.

Article 3.3 of Appendix 4 to the Annex 2 to the Chicago convention contains a remarkable requirement to unmanned balloons. Such vehicles are required to be equipped with at least two payload flight termination devices or systems. It may well be argued that such devises or systems are required for RPAS as well. An analogy to the operation of RPAS exists in Annex 2, which obliges pilots-in-command to take action as will best avert collision. The Annex also requires that vigilance for the purpose of detecting potential collisions be exercised on board an aircraft, regardless of the type of flight or the class of airspace in which the aircraft is operating.

It can therefore be concluded that pilots flying according to instrument flight rules are required to scan the environment visually in order to detect potentially conflicting traffic. If there is inability this might result in infringement of Article 3.2.1 of Annex 2, which provides that an aircraft shall not be operated in such proximity to the aircraft to create a collision hazard. A potential solution to this problem could be that movement sensors, based on radar or ultrasound devices, similar to parking assistants for cars, are built into RPAS. The drawback of such a measure would be the cost involved and the additional weight that has to be carried by the RPAS.

For further information and comment, please contact Arthur Flieger (, +32 3 238 77 66).

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