GENERIC UAS ATM SAFETY ASSESSMENT BASELINE SCENARIO 1 UAS IFR Operations In Classes A, B or C En-Route Airspace

GENERIC UAS ATM SAFETY ASSESSMENT BASELINE SCENARIO 1 UAS IFR Operations In Classes A, B or C En-Route Airspace [This generic UAS ATM Safety Assessment Baseline Scenario 1 for UAS applies only for flights under Instrument Flight Rules (IFR) within ICAO Classes A, B or C airspace. It must be noted this document does not constitute a concept of operations. The purpose of this document is to provide a framework which can be used to construct a generic safety case to facilitate the introduction of such operations in a consistent, coherent and safe manner into their airspace whilst offering continued safety to all existing users.] 3 rd October 2008 Version 1 1

GENERIC UAS ATM SAFETY ASSESSMENT BASELINE SCENARIO 1 CLASSES A, B OR C EN-ROUTE AIRSPACE 1. Introduction 1.1. The purpose of this document is to support the construction of a generic safety assessment for UAS 1 operations in Classes A, B or C en-route airspace. 1.2. The following assumptions have been made :- a) Airworthiness approval criteria are available and the UAS systems have been approved by the competent authority 2, b) The target is for seamless integration of UAS operations into the current European ATM 3 system, c) The integration of UAS should not make the airspace any less safe for existing users d)only single UAVs are considered 4, and therefore this document will require revision for future safety assessments, after ITU decisions on the frequency spectrum and once more will be known about the technical solutions for multiple command and control links operating simultaneously in the same airspace block; e)tcas 5 will not be available for a UA but will be in operation with other airspace users, f) Only IFR en-route operations in Classes A, B or C airspace are considered, and g)uas operations comply with the applicable ICAO requirements 6 except where explicitly shown below. 2. UAS Mode Of Operation 2.1. The mode of operation considered for this baseline scenario uses a command and control system (C2) known as Radio Line Of Sight (RLOS) or Beyond Radio Line of Sight (Satellite)(BRLOS). The operations shall take place beyond visual line of sight (BVLOS) of a pilot. 2.2 The pilot in command is positioned in the ground control station. His competence, currency and medical requirements are established and implemented by the competent authorities. The use of a chase vehicle is excluded. 2.3. Annex 6 Part 1 applies to UAS operations. 2.4. The primary mode of operation of a UAV should entail oversight by the pilot-incommand, who should at all times be able to intervene in the management of the flight as well as to communicate with ATC. 3. Duration of the UAS operation 1 UAS = Unmanned Aircraft System comprising a ground control station, an unmanned aircraft (UA), the UAS crew and operational processes including flight crew procedures. 2 The national aviation authority per UAS whose UAS is less than 150 Kg; EASA for the heavier aircraft. 3 ATM = Air Traffic Management 4 The World Radio Conference of 2011 is expected to address the issue of spectrum allocation for UAS operations. Until then it is impossible to consider a situation where more than a UAV operates is close proximity to other UAVs controlled by their own dedicated ground control stations. 5 TCAS is the manufacturers trademark for ICAO Airborne Collision Avoidance Systems (ACAS) and software version 7 is the current version in use. 6 It should be noted that in 2008 ICAO has activated a Study Group on the matter, which will assist the Air Navigation Commission in order to propose appropriate modifications to the ICAO Annexes, accommodating the case of UAS. 3 rd October 2008 Version 1 2

3.1. The duration of any operation is dictated by the demands of the task and can range from a few hours to a number of days. 4. Physical UAS Characteristics 4.1. The physical characteristics of the UAS will vary considerably but will be of any size and speed. Communications, navigation and surveillance requirements are appropriate for the airspace. 4.2. Some Classes A, B or C airspace requires aircraft to have minimum rates of climb/descent of 500 feet per minute which are usually designated within the AIP. 4.3. Some UA will not be able to comply with the requirements and will be unable to operate in such Classes A, B or C airspace, until these rules will be modified. 4.4. Rate one turns are expected from manned aircraft and the same criteria can be expected for a UA. 5. UAS Flight Performance 5.1. There is a likelihood that a wide range of UA will be capable of flying in Class A, B or C airspace each of which will vary in its flight performance. As an illustration only the table below indicates the range of capability exhibited by one type. OUTCAST Generic MALE UAV datasheet Climb rate Speed [ktas] Wingspan 20 m [ft/min] min max Length 10 m MSL - FL100 1200 90 170 Max TO mass 8000 lbs FL100-200 1000 120 230 Ceiling 45000 ft FL200-300 600 130 220 Max bank angle 30 deg FL300-400 400 150 190 5.2. Similar performance tables exist for a wide range of UA types. 6. C3 Characteristics (e.g.: RLOS) 6.1. For the purposes of this document, the UAS is considered to comprise 1 ground control station (GCS) and 1 Pilot in Command. 6.2. Only two forms of command and control should be considered and these are radio line of sight (RLOS) or beyond radio line of sight (BLOS) which employs a satellite relay system. 6.3. Radio propagation latency figures for round trip communications are in the order of minimum 0 seconds (i.e. instantaneous) and a maximum of 2 seconds. 6.4. The maximum permissible range of any link will determine the range from the GCS that can be reached and this may have an impact on the level that can be flown. 7. Airspace Classifications 7.1. ICAO Airspace Classifications are contained in ICAO Annex 11 Air Traffic Services Chapter 2 para 2.6. Classes A, B or C airspace is designated controlled airspace within which aircraft are given a mandatory ATC service. Therefore a UA operated as IFR will be separated from all other aircraft by ATC. 3 rd October 2008 Version 1 3

7.2. The airspace classifications with their respective visibility and distance from cloud criteria are shown in Appendix B although with this document considering only IFR operations this will not necessary be needed. 8. Flight Rules 8.1. For the purposes of the document ICAO Annex 2 standards and recommended practices applies 7. The requirements for IFR flight are contained in ICAO Annex 2 Rules of the Air Chapter 5. 8.2. For UAS operations the pilot is remote from the aircraft and UAS operations are new and they may not be able to comply with the existing criteria. While ICAO, as said above, might modify its SARPs, legal rules applicable in the EU or in other European States may be established. If necessary, according to the Chicago Convention, differences from the standards may be notified to ICAO. 8.3. Also contained within ICAO Annex 2 are the Rules of the Air (Chapter 3 refers). These are for the observance of all airspace users. The implications for UAS are that other airspace users will reasonably expect that another aircraft will manoeuvre against them in a way that conforms to these rules. This particularly applies to the rules contained in para 3.2 Avoidance of Collisions where failure so to do may result in a significant reduction in flight safety. 9. ATM UAS Operational Flight Planning 9.1. ICAO flight planning is an essential component for a safe flight in airspace Classes A, B or C, and is the responsibility of the air operator. The pilot-in-command must satisfy himself that the intended flight is viable and can be carried out safely. ICAO Annex 6 Part 2 Chapter 4 says The pilot-in-command shall not commence a flight unless it has been ascertained by every reasonable means available that the ground and/or water areas and facilities available and directly required for such flight and for the safe operation of the aeroplane are adequate, including communication facilities and navigation aids. Note. Reasonable means in this Standard is intended to denote the use, at the point of departure, of information available to the pilot-in-command either through official information published by the aeronautical information services or readily obtainable from other sources. 9.2. For the purposes of this document the term flight planning only applies to the functions and responsibilities contained within ICAO Annex 6 and ICAO Doc 4444 PANS- ATM which deal with the relationship between the operator/pilot with ATM. It does not include any additional mission planning activity that is necessary for the operator such as payload preparation, installation and recovery. 9.3. It is required that a flight plan be filed to ATM for Classes A, B or C IFR operations. 7 Assuming they have been legally transposed into appropriate instruments. 3 rd October 2008 Version 1 4

9.4. Indication to ATC that the flight is unmanned will be through the use of specific UAS aircraft type designators. 10. Segregated or not Segregated 10.1. The area of operations for this baseline scenario is non-segregated airspace. 11. Populated areas 11.1. Aircraft, including UA, will fly over populated 8 areas and the pilot is responsible for compliance with Annex 2 Chapter 5 para 5.1.2 requirements. 11.2. The density of populated areas over which the UA may fly could cause the flight to be constrained in some way by airworthiness considerations. 12. Communications 12.1. The requirements for UAS have to attain the same safety level than those for manned aircraft. For the latter ICAO Annex 2 says the following:- An aircraft operated as a controlled flight shall maintain continuous air-ground voice communication watch on the appropriate communication channel of, and establish two-way communication as necessary with, the appropriate air traffic control unit, except as may be prescribed by the appropriate ATS authority in respect of aircraft forming part of aerodrome traffic at a controlled aerodrome. (para 3.6.5.1. refers). 12.2. This equates to the following for UAS operations:- a) Voice communications are required between pilot in command and ATC as it is required for manned aircraft 13. Navigation 13.1. For UAS operating in Class A,B or C airspace the requirement for performance based navigation is the same as for manned aircraft. 13.2. The UA must be able to navigate to a safe and effective standard, under the control of the pilot in command. 13.3. RNP value exists for all controlled airspace. The navigation performance of a UAV shall be sufficient to achieve the published value. 13.4. Operational approval will state the navigational performance that an aircraft can achieve 14. Surveillance 8 The term populated has not been defined 3 rd October 2008 Version 1 5

14.1. A UA shall be equipped with a Mode S transponder and, possibly ADS-B. 14.2. Throughout Europe Mode S transponders are presently required in this class of airspace. ADS-B, within the EGNOS coverage area, if complemented by an adequate number of receiving stations on the ground, can be an equivalent means to achieve the same purpose. 15. See And Avoid 15.1. In any flight the pilot is responsible (Annex 2 para 3.2. refers) for following the principle of see and avoid (refer to para 21). In Classes A, B or C airspace, when flying IFR, this need is not reduced and vigilance by the pilot remains necessary even though ATC are providing separation against all other known aircraft. 15.2. The principles for navigation lights, whose requirements for manned aircraft are contained in ICAO Annex 2, in general apply to unmanned aircraft equally. Detailed requirements for UAS lighting may have to be developed. 16. Pilot competence 16.1. Requirements for licensing and medical fitness of flight crew for manned aircraft are contained within ICAO Annex 1 9. In the EU EASA has competence to establish such requirements for all categories of pilots, including those of UAS with MTOM above 150 kgs. 16.2. At the time of writing the ICAO UAS Study Group is working also on appropriate class rating(s) for UAS applicable world-wide. This document is based on Classes A and C indicated in Annex 1. 16.3. Annex 1 Chapter 2 para. 2.3. lays down requirements for private pilots and para 2.4 those required by commercial pilots. 16.4. Appendix 1 of the Annex gives the requirements for proficiency in languages used for radiotelephony communications 16.5. Annex 1 gives precise details of the flight instruction required to gain the qualifications set out therein. 16.6. ICAO Annex 6 Chapter 9 para 9.4.5. states requirements for single pilot operations in IFR or at night. 16.7. The UA pilot is assumed to be able to communicate with ATC to the same level as a manned aviation IFR pilot. 17. Weather 17.1. The UA pilot is responsible for briefing himself prior to the flight with respect to the flight itself and the ground control station(s). 17.2. The UA pilot must have the ability, through the use of communications, to receive meteorological information and warnings pertinent to the flight. 17.3. Available meteorological information is set out in ICAO Annex 3 10. 9 ICAO Annex 1 Personnel Licensing Version 10 July 2005 10 ICAO Annex 3 Meteorological Services For International Air Navigation Chapter 9. 3 rd October 2008 Version 1 6

17.4. The UA pilot must be able to assess the atmospheric conditions affecting both the UA and the ground station(s). 17.5. ATC may be able to provide limited weather avoidance information. 18. UAS Lighting Requirements and Signal Recognition 18.1. UAS operations by night and day are considered. 18.2. Aircraft lighting systems are mandated to ensure that pilots of both aircraft involved can accomplish collision avoidance when necessary. UA will need to conform to this principle. ICAO Annex 2 refers. It may be necessary to apply a specific requirement to UAVs lighting. 18.3. Annex 2 Appendix 2 deals with interception of civil aircraft. These procedures can be complex and require immediate action by the intercepted pilot. The ability to see and respond to such procedures by a UA pilot may be questionable, since in the case of UA by definition there are no human lives on board. 19. Contingency & Emergency UAS Recovery Procedures 19.1. Flight Manual and operational approval contains within them the procedures for operating the UAS. 19.2. When considering procedures for contingencies such as loss of command and control link it is essential to carefully consider the effect of such arrangements upon third parties whether airborne or on the ground. This aspect can be addressed during the pre-flight planning stage. 19.3. A set of common contingency procedures to be used by all UAS operators and ATS providers, should be established by airspace authorities. For example, in Classes A, B or C airspace, a loss of control link and any associated recovery procedures will have significant impacts on ATC and will directly affect other airspace users. 20. Other Airspace Users 20.1. Other airspace users will include manned IFR and VFR aircraft as well as other IFR UA. 21. Sense and Avoid 21.1. For the purposes of this baseline scenario the term avoid applies equally to other airspace users, weather and terrain. 21.2. In ICAO Doc 9854 Conflict Management is broken down into 3 activities namely:- i) Strategic Conflict Management, ii) Separation 11 Provision, and iii) Collision Avoidance (see para. 22 below) 11 Separation, where prescribed, is either vertical (1000ft normally) or horizontally (various distances expressed in nautical miles and dependent upon technical characteristics but typically 3, 5 or 10nm). 3 rd October 2008 Version 1 7

21.3. In ICAO Classes A, B and C separation is provided by ATC to all IFR flights. Separation minima is defined for Classes A, B, C and D ( between IFR traffic) 12. 21.4. The UAS sense and avoid system shall therefore be used in Classes A, B or C airspace for weather avoidance collision avoidance terrain avoidance atmospheric pollution avoidance (volcanic ash, smoke etc) 22. Collision Avoidance Function 22.1. Collision avoidance becomes necessary when separation provision fails and is a requirement for all aircraft, all classes of airspace, in all weather conditions and for all flight rules. 22.2. It is always the pilot s responsibility regardless of the airspace within which he is operating (see table below). Airspace Class 13 UAS Flight Rules Threat aircraft flight rules Separation provision A IFR IFR ATC UAS B IFR/VFR IFR/VFR ATC UAS C IFR IFR/VFR ATC UAS C VFR IFR ATC UAS C VFR VFR UAS UAS D-E IFR IFR ATC UAS D-E IFR VFR UAS UAS D-E VFR IFR/VFR UAS UAS F-G IFR/VFR IFR/VFR UAS UAS Collision Avoidance 22.3. The Collision Avoidance Function is applied when provision of standard separation minima between the UA and other aircraft has failed. 22.4. Collision avoidance takes place using a conflict horizon potentially smaller than that used for separation provision. Therefore when it becomes necessary the manoeuvres are typically more urgent than for separation assurance. The size of the conflict horizon for UAS is related to the flight performance of the UA. 22.5. During collision avoidance ATC will, when possible, only pass traffic information until the aircraft as reported returning to the previously acknowledged clearance. 22.6. Terrain avoidance is the UA pilot s responsibility except when ATC are using radar vectors to provide navigation to the aircraft. 22.7. Pre-flight planning is used to identify any terrain issues that a pilot needs to alert to before becoming airborne so that safe avoidance strategies can be formulated in a timely manner. 12 ICAO Annex 11 Chapter 5 refers. 13 ICAO Classifications 3 rd October 2008 Version 1 8

22.8. It is necessary for the pilot to be aware when terrain is present in real time and to be able to control the UA sufficiently well to ensure collision avoidance. Additionally the situational awareness of the pilot must be kept at an appropriately high level. 22.9. A UAS may achieve collision avoidance in a way that is different from manned aircraft. 23. Air Traffic Management 23.1. The UAS operator is responsible for compliance with all ATM requirements applicable to the flight. The UA pilot is responsible for compliance with ATC requirements. 23.2. Where applicable the UAS operator is responsible for interactions with the Central Flow Management Unit and for the acquisition of the relevant slots times. 24. Transfer of Control 24.1. Transfer of control between ATC sectors is identical for UA as for manned aircraft 24.2. ATC units transfer control between themselves using the data block shown on the radar screens. The data contained here is supplied by Mode S transponders or ADS-B equipment onboard aircraft. 24.3. Whilst telephone communications are available to ATC and this is acceptable for transfer of control, airspace in core Europe is heavily used and for safety and efficiency reasons para 24.2 above is the preferred solution. 25. Cross-Border Operations 25.1. Operations across multiple ATC control sectors (possibly cross-border) are included in the baseline scenario. 26. Interoperability 26.1. The requirements for Interoperability are contained within the relevant EASA Implementing Rule and apply to manned and unmanned aircraft equally. 26.2. This is an issue that is addressed in the airworthiness certification process. 27. Security(Datalink) 27.1. Security of the UAS command, control and communications link will be ensured. 28. Payload 28.1. Payload is considered external to the UAS system from an ATM perspective and is therefore not considered. 3 rd October 2008 Version 1 9

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Appendix A ICAO Guiding Principles 14 For ATM 1. Introduction. 1.1. The ATM system is based on the provision of services. This service-based framework considers all resources, inter alia, airspace, aerodromes, aircraft and humans, to be part of the ATM system. The primary functions of the ATM system will enable flight from/to an aerodrome into airspace, safely separated from hazards, within capacity limits, making optimum use of all system resources. The description of the concept components is based on realistic expectations of human capabilities and the ATM infrastructure at any particular time in the evolution to the ATM system described by this operational concept and is independent of reference to any specific technology. Based on these considerations the elements are predicated on the guiding principles that follow. 2. Drivers For Change 2.1. T he ATM environment, like so many other environments today, is driven by safety and, increasingly, by commercial or personal outcome expectations. There are standards in place for global interoperability, and many States systems have evolved within a standards framework to levels that are able to sustain their individual requirements. However, they now struggle or fail to meet the ever-growing user expectations of global harmonization and interoperability. 2.2. In 2000, a range of factors, including cost, efficiency, safety and national interest, drove change in the ATM system. Now, however, the driver for change must be ATM user expectations, within a framework of safety and business cases, and cost/benefit analysis. The operational concept identifies a range of user expectations; however, it is recognized that within the planning horizon, the set of solutions to provide expected benefits may change, and this will be identified and implemented through the safety and business case process. 3. Guiding Principles 3.1. Safety. The attainment of a safe system is the highest priority in air traffic management, and a comprehensive process for safety management is implemented that enables the ATM community to achieve efficient and effective outcomes. 3.2. Humans. Humans will play an essential and, where necessary, central role in the global ATM system. Humans are responsible for managing the system, monitoring its performance and intervening, when necessary, to ensure the desired system outcome. Due consideration to human factors must be given in all aspects of the system. 3.3.Technology. The ATM operational concept addresses the functions needed for ATM without reference to any specific technology and is open to new technology. Surveillance, navigation and communications systems, and advanced information management technology are used to functionally combine the ground-based and airborne system elements into a fully integrated, interoperable and robust ATM system. This allows flexibility across regions, homogeneous areas or major traffic flows to meet the requirements of the concept. 3.4. Information. The ATM community will depend extensively on the provision of timely, relevant, accurate, accredited and quality-assured information to collaborate and make informed decisions. Sharing information on a system-wide basis will allow the ATM community to conduct its business and operations in a safe and efficient manner. 3.5. Collaboration. The ATM system is characterized by strategic and tactical collaboration in which the appropriate members of the ATM community participate in the definition of the types and levels of service. Equally important, the ATM community collaborates to maximize system efficiency by sharing information, leading to dynamic and flexible decision making. 14 Source : ICAO Doc 9854 Global Air Traffic Management Operational Concept Version1 2005 3 rd October 2008 Version 1 11

3.6. Continuity. The realization of the concept requires contingency measures to provide maximum continuity of service in the face of major outages, natural disasters, civil unrest, security threats or other unusual circumstances. 4. Future ATM System 4.1.The ATM community s expectations should guide the development of the future ATM system. The ATM operational concept will guide the implementation of specific ATM technology solutions. It is crucial that the evolution to the global ATM system be driven by the need to meet the expectations of the ATM community and enabled by the appropriate technologies 3 rd October 2008 Version 1 12

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APPENDIX B ICAO AIRSPACE CLASSIFICATIONS The airspace classifications with their respective visibility and distance from cloud criteria are shown in the table below: Altitude band Airspace class Flight visibility Distance from cloud At and above 3 050 m (10 000 ft) AMSL Below 3 050 m (10 000 ft)amsl and above 900 m (3 000 ft) AMSL, or above 300 m (1 000 ft) above terrain, whichever is the higher A*** B C D E F G 8 km 1 500 m horizontally 300 m (1 000 ft) vertically A***B C D E F G 5 km 1 500 m horizontally 300 m (1 000 ft) vertically At and below 900 m (3 000 ft) AMSL, or 300 m (1 000 ft) above terrain, whichever is the higher A***B C D E --------------------------------- F G 5 km --------------------------- 5 km** 1 500 m horizontally 300 m (1 000 ft) vertically ------------------------- Clear of cloud and with the surface in sight Notes * When the height of the transition altitude is lower than 3 050 m (10 000 ft) AMSL, FL 100 should be used in lieu of 10 000 ft. ** When so prescribed by the appropriate ATS authority: a) flight visibilities reduced to not less than 1 500 m may be permitted for flights operating: 1) at speeds that, in the prevailing visibility, will give adequate opportunity to observe other traffic or low volume traffic and for aerial work at low levels. 2) in circumstances in which the probability of encounters with other traffic would normally be low, e.g. in areas of low volume traffic and for aerial work at low levels b) HELICOPTERS may be permitted to operate in less than 1 500 m flight visibility, if manoeuvred at a speed that will give adequate opportunity to observe other traffic or any obstacles in time to avoid collision. ***The VMC minima in Class A airspace are included for guidance to pilots and do not imply acceptance of VFR flights in Class A airspace. Fig 1 ICAO Airspace Classifications Flight Visibility and Distance From Cloud Criteria. 3 rd October 2008 Version 1 14

APPENDIX C SEE AND AVOID 1.1. ICAO Circular 213 (dated 1989) says 15 The practice of "see-and-avoid" is recognized as the primary method that a pilot uses to minimize the risk of collision when flying as an uncontrolled flight in visual meteorological conditions. "See-and-avoid" is directly linked with a pilot's skill at looking about outside the cockpit or flight deck and becoming aware of the surrounding visual environment. Its effectiveness can be greatly improved if the pilot can acquire skills to compensate for the limitations of the human eye. These skills include the application of effective visual scanning, the ability to listen selectively to radio transmissions from ground stations and other aircraft to create a mental picture of the traffic situation, and the development of habit patterns that can be described as "good airmanship" 1.2. The circular also considers those factors that contribute to collisions and concludes that traffic congestion and aircraft speeds are part of the problem 16. Therefore careful consideration of closure rates between UA and other airspace users will assist industry greatly in fixing performance figures for airworthiness certification. 1.3 These factors are all contributory causes, but the reason most often noted in the mid-air collision statistics reads "failure of pilot to see other aircraft" - in other words, failure of the see-and-avoid system. In most cases at least one of the pilots involved could have seen the other in time to avoid the collision if that pilot had been watching properly. Therefore, it could be said that it is really the eye which is the leading contributor to mid-air collisions. 1.4. All the above applies to UAS operations that are subject to this document. There are two issues that require addressing. Firstly the UAV must be seen by other airspace users and visual acquisition must be early enough for threat identification, deciding the most appropriate manoeuvre and then carrying it out. Manned aircraft are fitted with navigation and anti-collision lights and are generally painted in colours that enable early recognition by other users. This requirement is one for UAVs also. ---------------- 15 The underlined text is taken directly from the ICAO circular 16 In the head-on situation, for instance, a jet and a light twin-engine aircraft may have a closing speed of about 1 200 kmlh (650 kt). It takes a minimum of 10 seconds for a pilot to spot traffic, identify it, realize it is a collision threat, react, and have the aircraft respond. But two aircraft converging at 1 200 kmlh (650 kt) will be less than 10 seconds apart when the pilots are first able to see each other! The actual values quoted here may not apply to UAS covered by this baseline scenario but are included to be indicative. 3 rd October 2008 Version 1 15