Study UAS (Unmanned Aircraft System)

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Study UAS (Unmanned Aircraft System)

52ND ANNUAL CONFERENCE, Bali, Indonesia, 24-28 April 2013

WP No. 85

Study UAS (Unmanned Aircraft System)

Presented by TOC

Summary

A view on the situation of the unmanned aircrafts will be given in this working paper. A new era is rising in the aviation world, showing new and unexpected scenarios regarding the implementation of this new technology and its operational deployment. Some updates will be shown on possible ATM issues.

Industries are becoming everyday more interested in this concept and a massive introduction has to be expected by ATM operators.

Introduction

1.1.  Improvements in technology and communication in the past decade has allowed extensive development in the area of unmanned aircraft, capable of operating with a remote pilot based on the ground, or even no pilot at all. These aircraft vary in size, weight, and are used for both military and civilian purposes. The economic benefits of these aircraft are causing significant development and demands for the widespread introduction of them into the aviation environment, including operations amongst civilian aircraft in non-segregated airspace (most of the UASs nowadays operate only in temporarily or permanently closed airspace for their operations (segregated areas)).

1.2.  A variety of terminology exists in the industry and can cause some confusion:

  • UAS defines Unmanned Aircraft System, and is a generic term to describe all aircraft flown without a pilot on board, this was formerly termed Unmanned Aircraft Vehicle (UAV).
  • RPAS is a Remotely Piloted Aircraft System, whereby a pilot located on the ground operates a Remotely Piloted Aircraft (RPA) also known as a Remotely Piloted Vehicle (RPV).
  • There are also aircraft capable of flying entirely without a pilot, either on board or on the ground. There aircraft are mostly known as Autonomous Unmanned Aircraft Systems (AUAS).
  • The mass media refer to all of these simply as “drones”.

1.3.  The ICAO regulatory framework does not yet recognize autonomous aircraft and focuses on RPAs only.

1.4.  For simplicity, throughout this paper the term UAS will be used to refer to all kinds of unmanned aircraft unless specified otherwise.

1.5. This working paper will summarize the latest development in UAS, and highlight the issues that pose significant concern for IFATCA.

Discussion

2.1. UAS types and categories

2.1.1  UASs are actually divided into 5 types: Micro, Mini, Small, Tactical and Strategic. This classification is only for military purposes and is based on the differences in weight and kind of mission” of the UAS (nowadays 99% of the UASs is for military purposes. Only in few cases of civil purposes – some low weight UASs are used (“micro” <2 Kg. or “mini” <30 Kg.) which fly at low altitude). It doesn’t adhere at all with the wake turbulence category which could interest ATM.

2.1.2  NASA and the Federal Aviation Administration (FAA), has developed a different classification that takes into account only of the take-off weight as in the following chart:


2.2. Operational case

2.2.1. One of the most active UAS is the Global Hawk. This “large” or “strategic” UAS has performances and dimensions that are similar to an actual aircraft and so the necessity to eventually integrate it into national airspaces requires compliance of certain rules.

2.2.2  Global Hawk isn’t equipped by some means (e.g. RVSM capacity and 8.33KHz radio) which are usually required for aircraft that are intended to fly within the same portion of airspace where this UAS flies (up to 60.000 ft.). As a result, the coordination between ATS provider and the regulator has led to the establishment of specific segregated airspaces, to allow the UAS to fly to the operational area.

2.2.3  A good example of operational issue is about the Global Hawks operating from Sigonella military airport (Italy – LICZ). These UASs are not permitted to fly where other standard traffic is (non- segregated airspace). At every opportunity a Global Hawk needs to take off or land in Sigonella, the adjacent civil airport of Catania Fontanarossa (LICC) is closed to all airborne operations causing the issue of delays to all other traffic.


2.3. ATM issues

2.3.1.  To allow UASs to fly in non-segregated airspaces, it should be mandatory for these systems to carry the standard equipment required to operate in such airspaces and to comply with the minimum required navigation and communication performances. If should this be the way, there will be the need to close the technological gap between UASs and other aircraft (ACAS 2, Data Link, Mode S, etc.) and to speed up the chase in an ATM world which is fast moving from the “First to come, first to be served” concept to a “Best equipped, best served” or even “Best performing, best served” concept.

2.3.2.  Just to give an example, a comparison between some of the features of the Global Hawk (RQ- 4B) and the last version of the Boeing 737 is given in the following chart:

As it can be figure out from the chart, some of the features of the Global Hawk are homogeneous with other commercial aircraft with which it could interact. This makes large or HALE (High Altitude Long Endurance) UASs a real challenge for ATM.

2.3.3  Another interesting example about performance improvement in all UASs category is that mini systems, despite their limited weight and size (<30Kg.), are capable to fly up to 10,000ft. of altitude and 15 NM of range. Mini systems should be operated in Line Of Sight (LOS) operations but according to their performance, nothing could limit their way to go Beyond Line Of Sight (BLOS). The framework boundary between model aircrafts and UASs is getting thin.

2.3.4  UAS operation in non-segregated airspaces could mitigate any interaction issue by flying in segregated airspace until reaching an altitude which is above the normal ones (like >FL 550). In recent years considerable interest and effort has been expended world-wide into the development of technologies, ATM procedures, UAS operational approvals and UAS certification standards that will allow UAS to become fully integrated into the Air Traffic Management (ATM) environment.


2.4. IFATCA policy

2.4.1.  IFATCA policy related to unmanned aircraft is:

AAS 1.10 OPERATIONAL USE OF UNMANNED AIRCRAFT (UA)

All Unmanned Aircraft Systems (UAS) operations in non-segregated airspace must be in full compliance with ICAO requirements.

Air Traffic Controllers must not be expected to handle an UA in a different way from any other aircraft for which they are providing service.

 

2.4.2.  TOC’s opinion is that this policy is valid and solid to state the need for every aircraft to be fully ICAO compliant, even it is “manned” or not. According to this first statement, the policy stresses the concept that ATCOs shall not provide services to UASs differently from other aircrafts. Otherwise this could lead to mixed mode operations.

2.4.3.  Whenever it is decided to allow the coexistence of non-ICAO compliant UASs in non-segregated airspace there should be the need for “ad-hoc” rules (that need to be less restrictive) or even as it used to do nowadays for military traffic.

2.4.4. This occurrence will be as like as a mixed mode operation, a working method about which IFATCA has a specific policy, as follows:

ATS 3.14 MIXED MODE OPERATIONS

Mixed mode operations are defined as ATM Operations that require different procedures due to variances in airspace users’ characteristics and/or ATM design within the same area of controller responsibility.

Efforts should be undertaken to reduce existing Mixed Mode Operations by creating intrinsically safe solutions.

Introductions of new Mixed Mode Operations should be avoided by creating intrinsically safe solutions.

When safety of a Mixed Mode Operation cannot be completely managed at an intrinsic level, assessment must take place that the change in the ATM system does not increase controller workload to an unacceptable level.

 


2.5 ICAO

2.5.1  Circular 328 on UAS is, as any other ICAO Circular, just a guidance. The ICAO Secretariat is planning to develop a more detailed UAS Manual.

2.5.2  To deal with UAS, ICAO established in November 2007 a UAS Study Group. The European contribution to this Group so far, has been provided by EASA and Eurocontrol.

The 37th General Assembly (October 2010) recommended ICAO to include the development of standards for UAS in its work programme. Amendment 13 to Annex 13 (Accident Investigations) officially recognises that UAS are within the regulatory competence of aviation authorities while ICAO Circular 328 published in March 2010, covers legal matters, OPS, FCL, airworthiness and systems.

EASA will contribute with regard to safety objectives, oversight of communication service providers and flight crew licensing.

2.5.3  On 7 March 2012, the ICAO Council adopted Amendment 43 to ICAO Annex 2. This amendment clarifies that priority should be given to the insertion of RPAS into the “total civil aviation system” (i.e. first airworthiness, then operations and flight crew licensing and finally insertion into ATM).

2.5.4  UAS operating in non-segregated airspace shall comply with all prescribed requirements as any other aircraft including the requirement to see and avoid other traffic. ICAO has defined the new term “detect and avoid” in Amendment 43 of Annex 2 as follows:

New Annex 2 Definitions:

Command and control link (C2). The data link between the remotely piloted aircraft and the remote pilot station for the purposes of managing the flight.

Detect and avoid. The capability to see, sense or detect conflicting traffic or other hazards and take the appropriate action.

Remotely piloted aircraft (RPA). An unmanned aircraft which is piloted from a remote pilot station.

2.5.5  The “Detect and Avoid” procedure must be as safe and reliable as the eyeball view used for the “See and Avoid” procedure. But since the issue of detect/sense is linked to independence and redundancy of the devices it might be that the separation layer and the anti-collision layer will fail both due to the very same reason (e.g. failure of the equipment used for both of them). The FAA has told lately (quite openly) that some of the Annex 2 requirements can possibly never be fully met by UAS. Technically speaking the limitations are big.

2.5.6  ICAO Aviation System Block Upgrades (ASBU). Blocks B1-90, B2-90 and B3-90 are the steps which has been created in the attempt to bring UASs into operational non-segregated airspace.

2.5.7  ICAO recognize that any delay in developing provisions could lead to the implementation of a variety of interim, non-harmonized national provisions, with subsequent compliance issues. In this case the costs for industry could be much higher than necessary.

2.5.8  The ICAO UAS-Study Group (UAS SG) is active on the development of a Manual, to be ready for the 2014 world-wide Symposium. It could be a starting point for new amendments to other Annexes to the Chicago Convention.

2.5.9  During the meeting between Airborne Surveillance Task Force (ASTAF) and the UAS-Study Group of ICAO held in Montreal in April 2012 the different options and issues/problems for the safe integration of UASs were pin-pointed and discussed.

2.5.9.1  It became evident that See and Avoid cannot fully work for non-manned aircraft, even with very sophisticated electronic devices since it can’t actually achieve the same degree of flexibility and the same level of safety of an on-board pilot eye view. Worse even for the very complex priority rules for avoiding traffic visually as stated on Annex 2 §3.2.2 “Right-of-way” rules (avoiding traffic visually with no risk of collision).

2.5.9.2  So the only way forward in certifying UAS to permit their integration into non-segregated airspace is by using “the equivalent level of safety” arguments. Which means to “find” procedures or technologies that would achieve the same level of safety that we have right now.


2.6 Upcoming aspects

2.6.1  Medical/psychological studies on piloting in a remotely manner demonstrated that situational awareness may be less than piloting an aircraft being on-board of it. The challenge can become greater considering that since 2012 USAF is testing operations of 4 UASs at once managed by a single remote pilot.

2.6.2  Other interesting issues are the technological aspects that highlights how many industries are elaborating even more advanced UAS concepts with an upgrading autonomy level (meaning with this the capability to be autonomous in decision making from humans).

2.6.3  There are ten levels or steps that lead this systems to the complete autonomy even if it is still far to be carried out. Nowadays we can only talk about “automation”, the human is still the core of the system (“man in the loop”).

The following chart shows the ten steps which will bring UASs to full autonomy:

2.6.4  Aviation industries are developing the evolution of the “Detect and Avoid” concept, called “Sense and Avoid”, in which several sensors and apparatus sends their readings to a central system that decides the most appropriate avoiding action.

2.6.5  Industry has already developed UASs which are capable of operating autonomously in some phases of the flight (by the time for take-off, landing and obstacle avoidance) and will continue on switching even more and more aspect of the UAS flight to autonomy.

2.6.6  EDA (European Defence Agency) is the contracting authority for MIDCAS (MID air Collision Avoidance System).

This project is developing an avoidance system for both military and civil purposes according to the following policy:

“The MIDCAS mission is to demonstrate the baseline of solutions for the Unmanned Aircraft System (UAS) Midair Collision Avoidance Function (including separation), acceptable by the manned aviation community and being compatible with UAS operations in non-segregated airspace by 2015”.


2.7 Integration issues

2.7.1  Any legal aspect related to UAS brings new issues. In article 8 of the 1944 Chicago Convention on Civil Aviation is mentioned that:

“No aircraft capable of being flown without a pilot shall be flown without a pilot over the territory of a contracting State without special authorization by that State and in accordance with the terms of such authorization…”

2.7.2  While the Global Air Traffic Management Operational Concept (Doc 9854), confirms Article 8 and states:

“An unmanned aerial vehicle is a pilotless aircraft, in the sense of Article 8 of the Convention on International Civil Aviation, which is flown without a pilot-in-command on-board and is either remotely and fully controlled from another place (ground, another aircraft, space) or programmed and fully autonomous.”

2.7.3  Nowadays an aircraft can be considered as a “closed system”: flight controls are directly linked to the pilot who is inside the airplane and therefore anyone who has the intent to hijack the plane should be inside the aircraft itself. An UAS is an “open system” instead. Anyone who has the capability to intercept the communication between the remote pilot and the aircraft could take control of it as demonstrated by Professor Todd Humphreys and his team at Austin’s Radionavigation Laboratory at the University of Texas.

2.7.4  One of industries’ objective will be to make UASs control transmissions as secure as possible. ICAO UASSG is addressing this issue.

2.7.5  Every time the link between the UAS and the remote pilot is lost, most modern systems have a “Lost-Link Procedure”. It includes a determined behaviour taken by the UAS in terms of specific path to get back to the departure airfield or to another specified one. While some States have a published procedure for such an event, serious issue could arise if such procedure is not known by the ATCOs since it could bring the UAS into unexpected flight path and/or into unexpected airspaces.

2.7.6  In 2010 EUROCONTROL commissioned a study to demonstrate that there is a need for UAS to have a collision avoidance capability comparable to that delivered by ACAS on manned aircraft (see further reading). On July the 1st 2010 the first European High Level Conference on Unmanned Aircraft Systems was held in Brussels. Since this meeting it became evident that UAS technology is being promoted for economic reasons.

The very first point of the 15 final steps the participants decided to initiate was:

“a) Unmanned Aircraft Systems must be able to operate without segregation from other airspace users to allow the development of their full potential…”

Despite many other political, economic, industrial and ethical issues, the UAS insertion into ATM airspace is being considered the first and most important topic to allow further industrial and civil development.

2.7.7  Since UAS world is evolving, it becomes necessary to rule its activities. On April 11th 2012 SESAR JU started a study on possible UAS integration in non-segregated airspace. This program is called ICONUS (Initial CON OPS for UAS in SESAR). It will be kept by a 6 Associate Partners team of several European states with the aim of defining the minimum performance requirements and to study the way to implement new separation methods.

2.7.8  EUROCAE within the European UAS expert group, WG-73 is working with EASA in the development of airworthiness criteria and Special Conditions to supplement EASA A-NPA-16 Policy for Unmanned Aerial Vehicle (UAV) Certification. The result of these studies led to the same issues seen before on the necessity to get a high level of security on Command and Control transmission.

2.7.9  European Defense Agency (EDA) has created the SIGAT project – Study on the Insertion of UAS in the General Air Traffic, a consortium of EADS, Sagem, BAE and Dassault. This agency has proven UASs advantages for many applications and considers the ability for UAS to share civil airspace with other aircraft in General Air Traffic (GAT) a major milestone. It is anyway concerned on Command & Control (C2) radio-frequency data-link and the use of a Sense & Avoid (SAA) system for anti-collision purposes which still miss a specific spectrum allocation.

2.7.10  After recognizing the dramatic grow of military UAS operations and the possibility to mirror these activity in civil sector, the European Commission started a panel for the support of the introduction of UAS in the European airspace.

2.7.11  After some preliminary hearings about light UAS activity, the Commission decided in 2012 to launch the “UAS panel initiative” with the aim of supporting the industrial and customer needs to develop a European UAS market. The workshops allowed a wide consultation of all stakeholders on the following topics: RPAS Industry and Market, RPAS insertion into airspace and radiofrequencies, Safety of RPAS, Societal dimension of RPAS and Research and development for RPAS.

2.7.12  The conclusions of these debates produced the document “Towards the Development of Civil Applications of Unmanned Aircraft Systems (UAS), a Strategy for the European Union”, that was presented to the UAS panel on May the 2nd 2012 meeting.

The Staff Working Paper foresees the completion of the Roadmap in the first quarter of 2013 and proposes that the initial insertion of RPAS in non-segregated airspace would be achieved in 2016. These deadlines take account of the recent announcement by the US to mandate the FAA to prepare for the RPAS insertion in the national airspace in 2015.

2.7.13  In 2011 over 600,000 hours of flight has been collected by UASs in USA only. NextGen program, FAA and NASA have included an integration process for UASs in non- segregated airspaces. This committee is working jointly with FAA’s Unmanned Aircraft Program Office (UAPO) and with RTCA Special Committee 203 (SC-203).

2.7.14  The technical challenges and issues which came out from this projects are similar to those studied in Europe and are about a general lack of technology and procedures dedicated to airborne separation, minimum performance standards and testing.

The Separation Assurance/Sense and Avoid Interoperabilty (SSI) subproject will measure the impact of this increase on the air traffic control system’s ability to ensure separation for several future UAS integration scenarios, both under today’s operations and in NextGen.

2.7.15  The US Code of Federal Regulations (CFR) clearly defines the legal framework for pilots on “see and avoid” operations. Future Sense and Avoid (SAA) systems will provide operators with some level of surveillance information about aircraft near the unmanned aircraft and, as for TCAS, NASA expect to see operators manoeuvring the UAS to avoid other aircraft without ATC coordination. Simulation flights will take place in 2015 and 2016.

2.7.16  NASA is also developing the Human Systems Integration (HSI), a research test-bed and database to provide data and proof of concept for Ground Control Station (GCS) operations.

2.7.17  The American Institute of Aeronautics and Astronautics has developed a model of mid-air collisions between UASs and other aircraft which takes into consideration various aspects like air traffic density data from the FAA to determine the expected number of collisions per hour. The analysis provides insight into the variation of collision risk with respect to structure of the NAS and the possibility of low-risk operating strategies and requirements for mitigation.

The reliability is already within the requirements demonstrated by several current UASs. To satisfy mid-air collision safety requirements an active mitigation measures could include using frangible UASs that impart less damage to other aircraft and being equivalent to a bird strike.

2.7.18  Significant mitigation would be required to operate bigger drones like High Altitude and Long Endurance (HALE) UAS. High altitude UASs pose greater risk than other classes so they will need to incorporate more sophisticated mitigation measures to prevent mid-air collisions such as “sense and avoid” systems, or active air traffic control separation, which are all items under construction.

This study recognized how a significant increase of UAS operations are expected to emerge in the future. The type and magnitude of mitigation employed to meet system safety standards will vary significantly between classes of UASs.

New studies that to consider the ICAO separation minima and the related airspace infringement case are required.

2.7.19  The United States Government Accountability Office (GAO) studied the safe integration of UAS into US national airspaces in September 2012. As stated in the report, a lot of work has been done, but additional work is needed to overcome many of the obstacles to the safe integration like the Sense and Avoid issues and the vulnerabilities in the Command and Control of UAS operations. GAO recognized that, even if FAA has taken steps to meet the requirements, it is uncertain when the US airspace system will be ready to accommodate UAS.

2.7.20  GAO is also concerned about national security, privacy, and the interference in Global Positioning-System (GPS) signals that have not been resolved and therefore may influence acceptance of routine access for UAS in non-segregated airspace. Non-military UAS GPS signals are unencrypted, risking potential interruption or hacking of Command and Control signals.


2.8 IFALPA’s Position on UAS

2.8.1  IFALPA believes that UAS technology is not capable of replacing human capabilities, particularly in complex and safety-critical situations. Therefore, IFALPA strongly opposes the use of UAS to supplant the role of pilots in any type of air transport operations.

2.8.2  According to IFALPA’s position, the safe integration of UAS operations into civilian, non- segregated airspace can only be achieved if UAS are regarded in all ways as aircraft. UAS and their operations must comply with all existing rules and regulations applicable to other aircraft in the same class of airspace. It is not acceptable for such rules and regulations to be changed for manned aviation in order to integrate UAS and their operation.

2.8.3  As a subset of UAS, Remotely-Piloted Aircraft Systems (RPAS) should be fully certified and compliant with the provisions described herein before being allowed to operate in non-segregated public airspace. Non-compliant UAS will require segregated airspace or mitigation by special authorizations.

Conclusions

3.1.  UAS integration in ATM airspaces need a step-by-step path.

3.2.  TOC’s opinion is that every aircraft, manned or not, operating in non-segregated airspaces, shall be compliant with ICAO requirements.

3.3.  Industry is pushing to bring UASs into the same airspace used by manned flights but using different capabilities.

3.4.  UAS operations in non-segregated airspace have already started.

3.5.  Any new concept must first of all take into consideration all the safety aspects. The responsibility and liability framework between humans and machines must be clearly defined.

3.6.  In the event of a “Lost Link”, ATCOs may not be aware of the behaviour of the involved UAS. It is essential that “Lost-Link” procedures are developed and implemented.

3.7.  In opinion of TOC, IFATCA policy on UAS is valid and solid.

Recommendations

It is recommended that:

This paper is accepted as information material.

References

IFATCA Professional and Operational Manual 2012 – AAS 1.10 OPERATIONAL USE OF UNMANNED AIRCRAFT (UA) and ATS 3.14 MIXED MODE OPERATIONS.

ICAO Circular 328 AN/190 Unmanned Aircraft System (UAS).

ALIAS – Using Scenarios to discuss liability issues of UAS.

043-44_Contributing-Stakeholder_ICAO-UAS-Study-Group.

EASA Policy Statement Doc # E.Y01301 Airworthiness certification of Unmanned Aircraft Systems (UAS).

46th Single Sky Committee – European Strategy in support of the UAS sector 14/15 June 2012 (Submitted by the European Commission).

Amendment 43 to ICAO Annex 2.

http://www.sesarju.eu/news-press/news/sesar-launches-study-unmanned-aircraft-1070.

Conclusions of the first European High Level Conference on Unmanned Aircraft Systems – Brussels, 1st July 2010.

Flieger Law Office bvba newsletter Sept. 2012: “Unmanned aerial systems: towards an European legislation or global regulatory system?” By Arthur Flieger, Attorney at law Flieger Law Office bvba with the cooperation of Stijn Brusseleers, Attorney at law Flieger Law Office bvba.

http://www.skybrary.aero/index.php/Unmanned_Aircraft_Systems.

Eurocontrol – ATM Guidelines for Global Hawk in European Airspace.

EASA News 11 (July 2012).

ICAO DOC 4444 ATM/501 Procedures for Air Navigation Services.

ICAO AN-Conf/12-WP/14 Aviation System Block Upgrade modules relating to integration of Remotely Piloted Aircraft (RPA) into non-segregated airspace.

American Institute of Aeronautics and Astronautics: “For Spacious Skies: Self-Separation with “Autonomous Flight Rules” in US Domestic Airspace” by David J. Wing (NASA Langley Research Center, Hampton, VA, 23681) and William B. Cotton (National Institute of Aerospace, Hampton, VA, 23666).

Centro Alti Studi della Difesa – Remotely Piloted Systems: Aspetti etici del loro impiego – Rome, May the 2nd 2012.

USAF RPA Update – Looking to the Future by Col J.R. Gear Director, USAF RPA Task Force, 3 Jun 2011.

IFALPA Position – The Global Voice of Pilots 13POS04 (12 October 2012).

www.midcas.org.

Drones vulnerable to terrorist hijacking, researchers say by John Roberts June 25, 2012 – www.foxnews.com.

European Defence Agency – SIGAT – Study On Military Spectrum Requirements for the Insertion of UAS Into General Air Traffic.

2012 RPAS Yearbook – The Global Perspective – 10th Edition, June 2012.

John Croft: “Advisers Caution FAA on Unmanned Vehicle Integration” – Aviation Week, October 16, 2012.

American Institute of Aeronautics and Astronautics : Safety Considerations for Operation of Different Classes of UAVs in the NAS by Roland E. Weibel and R. John Hansman, Jr. – Massachusetts Institute of Technology, Cambridge, MA 02139.

European Commission: SSC/12/46/18 Agenda Item 11.1, 31 May 2012.

United States Government Accountability Office: Highlights of GAO-12-981, a report to congressional requesters: Unmanned Aircraft Systems – Measuring Progress and Addressing Potential Privacy Concerns Would Facilitate Integration into the National Airspace System (September 2012).

Appendix

This appendix is intended to provide readers with all the information collected by TOC for the UAS working paper that didn’t gain sufficient room in the WP itself. The following information are to be considered as an integration to the main working paper which expresses already all the major issues and IFATCA’s opinions on UAS.


6.1 An operational case

6.1.1  Nowadays one of the most active UAS in the Italian airspace is the Northrop “Global Hawk”. This “large” or “strategic” UAS (depending on the definition) starts its activity taking off from Sigonella airport (LICZ) located on Sicily island, south of Italy. The performances and the dimensions of this machine are similar to the ones of an actual aircraft and so the necessity to eventually integrate it into national airspaces requires compliance of certain rules.

The Global Hawks based in Sigonella have already reached more than 1,000 hours of flight and almost the same activity is being carried with Predator B UASs on Foggia Amendola airport (LIBA – Apulia, south Italy) where is located the Remotely Piloted Aircraft Reference Centre (Centro di Eccellenza per Aeromobili a Pilotaggio Remoto – CdE APR). The Italian Air Force has already operated drones for more than 10,000 hours in both national and international environment. Industries in Italy as well as in the rest of the industrialized world are getting more and more involved in this technology.

6.1.2  Global Hawk isn’t equipped by some means (e.g. RVSM capacity and 8.33KHz radio) which are usually required for aircraft that are intended to fly within the same portion of airspace where this UAS flies (up to 60.000 ft.). As a result, the coordination between ATC provider ENAV and the regulator ENAC has led to the establishment of specific segregated corridor airspace, to allow the UAS to fly to the operational area.

6.1.3  Up to date, any request of the remote pilot to be rerouted on a direct track that brings the UAS outside of the segregated area is denied by the ATC unit. In addition to this, since the UAS is not permitted to fly where other standard traffic is, at every opportunity a Global Hawk needs to take off or land in Sigonella airport, the adjacent Catania Fontanarossa airport is closed to all airborne operations causing the issue of delays to all other traffic.

6.1.4  In recent years considerable interest and effort has been expended world-wide into the development of technologies, ATM procedures, UAS operational approvals and UAS certification standards that will allow UAS to become fully integrated into the Air Traffic Management (ATM) environment.

In 2010 EUROCONTROL have commissioned a study to demonstrate that there is a need for UAS to have a collision avoidance capability comparable to that delivered by ACAS on manned aircraft (see further reading).


6.2 The future of European research

6.2.1 On July the 1st 2010 the first European High Level Conference on Unmanned Aircraft Systems was held in Brussels. One of the key elements which came out was:

“…The participants in the Conference agreed that the emergence of Unmanned Aircraft Systems sector is a promising new chapter for the aerospace domain and for the aviation industry. Europe has a robust industrial and technology baseline for UAS to assume a leading competitive position in this new growth sector. Capitalising on this growth potential could create thousands of high technology jobs for Europe. We need to be proactive in order to enhance the competitive position of European industries, SMEs, research and service providers.

Once the existing barriers to growth are removed, the civil market could be potentially much larger than the military market. Exponential growth could be expected once user applications are developed and a legal framework is set up.”

And the very first point of the 15 final steps the participants decided to initiate was:

“a) Unmanned Aircraft Systems must be able to operate without segregation from other airspace users to allow the development of their full potential…”

Despite many other political, economic, industrial and ethical issues, the UAS insertion into ATM airspace is being considered the first and most important topic to allow further industrial and civil development.

6.2.2  Since UAS world is evolving, it becomes necessary to rule its activities. On April 11th 2012 SESAR JU started a study on possible UAS integration in non-segregated airspace. This program is called ICONUS (Initial CON OPS for UAS in SESAR). It will be kept by a 6 Associate Partners team of several European states and will be leaded by the French organization ONERA together with AVTECH (Sweden); CIRA and Deep Blue (Italy); ENAC (France) and INTA (Spain).

The aim of ICONUS is to define the minimum performance requirements and to study the way to implement new separation methods. This study shall show how UASs will be affected by the future ATM changes that is moving from airspace-based operations (in which the users are completely subject to the airspace constrains) to trajectory-based operations (where all the ATM will operate among all of its component to guarantee to the aircraft the best available trajectory according to its preferred route).

6.2.3  To deal with UAS, ICAO established in November 2007 a UAS Study Group. The European contribution to this Group so far, has been provided by EASA and Eurocontrol. The 37th General Assembly (October 2010) recommended ICAO to include the development of standards for UAS in its work programme.

Amendment 13 to Annex 13 (Accident Investigations) officially recognises that UAS are within the regulatory competence of aviation authorities while ICAO Circular 328 published in March 2010, covers legal matters, OPS, FCL, airworthiness and systems. ICAO also plans to develop an UAS Manual that should be finalized in 2013.

EASA will contribute with regard to safety objectives, oversight of communication service providers and flight crew licensing.

6.2.4  Germany undertook a safety case for Euro Hawk flying in ATM airspace above FL 100 and considered it to be safe. Global Hawk and Euro Hawk operations on a low scale in Germany and Italy are expected to be performed as stated on the “ATM Guidelines for Global Hawk in European Airspace” by Eurocontrol:

“The GH operations described are flown by the military, and are therefore classed as Operational Air Traffic (OAT). These Guidelines accordingly follow the same basic ATM principles as the EUROCONTROL Specifications for the Use of Military UAS as OAT, namely that:

  • UA operations should not increase the risk to other airspace users;
  • ATM procedures should mirror as much as possible those applicable to manned aircraft;
  • The provision of air traffic services to UAS should be transparent to ATC controllers.”

6.3 ICAO

6.3.1 ICAO published the Amendment 43 of the Annex 2 “Rules of the Air”. Among the topics addressed by this document, there is the level requirements related to remotely piloted aircraft systems.

In this edition several new definitions (including “detect and avoid”) and operating rules related to the UASs are given as follows:

New Annex 2 Definitions:

Command and control link (C2). The data link between the remotely piloted aircraft and the remote pilot station for the purposes of managing the flight.

Detect and avoid. The capability to see, sense or detect conflicting traffic or other hazards and take the appropriate action.

Operator. A person, organization or enterprise engaged in or offering to engage in an aircraft operation.

Note. In the context of remotely piloted aircraft, an aircraft operation includes the remotely piloted aircraft system.

Remote pilot. A person charged by the operator with duties essential to the operation of a remotely piloted aircraft and who manipulates the flight controls, as appropriate, during flight time.

Remote pilot station. The component of the remotely piloted aircraft system containing the equipment used to pilot the remotely piloted aircraft.

Remotely piloted aircraft (RPA). An unmanned aircraft which is piloted from a remote pilot station.

Remotely piloted aircraft system (RPAS). A remotely piloted aircraft, its associated remote pilot station(s), the required command and control links and any other components as specified in the type design.

RPA observer. A trained and competent person designated by the operator who, by visual observation of the remotely piloted aircraft, assists the remote pilot in the safe conduct of the flight.

Visual line-of-sight (VLOS) operation. An operation in which the remote pilot or RPA observer maintains direct unaided visual contact with the remotely piloted aircraft.

APPENDIX 4. REMOTELY PILOTED AIRCRAFT SYSTEMS

1. General operating rules

1.1 A remotely piloted aircraft system (RPAS) engaged in international air navigation shall not be
operated without appropriate authorization from the State from which the take-off of the remotely piloted aircraft (RPA) is made.

1.2 An RPA shall not be operated across the territory of another State, without special authorization issued by each State in which the flight is to operate. This authorization may be in the form of agreements between the States involved.

1.3 An RPA shall not be operated over the high seas without prior coordination with the appropriate ATS authority.

1.4 The authorization and coordination referred to in 1.2 and 1.3 shall be obtained prior to take-off if there is reasonable expectation, when planning the operation, that the aircraft may enter the airspace concerned.

1.5 An RPAS shall be operated in accordance with conditions specified by the State of Registry, the State of the Operator if different and the State(s) in which the flight is to operate.

1.6 Flight plans shall be submitted in accordance with Chapter 3 of this Annex or as otherwise mandated by the State(s) in which the flight is to operate.

1.7 RPAS shall meet the performance and equipment carriage requirements for the specific airspace in which the flight is to operate.

2. Certificates and licensing

Note 1.-Assembly Resolution A37-15 Appendix G resolves that pending the coming into force of international Standards respecting particular categories, classes or types of aircraft, certificates issued or rendered valid, under national regulations, by the Contracting State in which the aircraft is registered shall be recognized by other Contracting States for the purposes of flight over their territories, including landings and take-offs.

Note 2.-Certification and licensing Standards are not yet developed. Thus, in the meantime, any certification and licensing need not be automatically deemed to comply with the SARPs of the related Annexes, including Annexes 1, 6 and 8, until such time as the related RPAS SARPs are developed.

Note 3.-Notwithstanding the Assembly Resolution A37-15, Article 8 of the Chicago Convention assures each Contracting State of the absolute sovereignty over the authorization for RPA operation over its territory.

2.1 An RPAS shall be approved, taking into account the interdependencies of the components, in accordance with national regulations and in a manner that is consistent with the provisions of related Annexes. In addition:

a) RPA shall have a certificate of airworthiness issued in accordance with national regulations and in a manner that is consistent with the provisions of Annex 8; and

b) the associated RPAS components specified in the type design shall be certificated and maintained in accordance with national regulations and in a manner that is consistent with the provisions of related Annexes.

2.2 An operator shall have an RPAS operator certificate issued in accordance with national regulations and in a manner that is consistent with the provisions of Annex 6.

2.3 Remote pilots shall be licensed or have their licences rendered valid, in accordance with national regulations and in a manner that is consistent with the provisions of Annex 1.

3. Request for authorization

3.1 The request for authorization referred to in 1.2 above shall be made to the appropriate authorities of the State(s) in which the RPA will operate not less than seven days before the date of the intended flight unless otherwise specified by the State.

3.2 Unless otherwise specified by the State(s), the request for authorization shall include the following:

a) name and contact information of the operator;

b) RPA characteristics (type of aircraft, maximum certificated take-off mass, number of engines, wing span);

c) copy of certificate of registration;

d) aircraft identification to be used in radiotelephony, if applicable;

e) copy of the certificate of airworthiness;

f) copy of the RPAS operator certificate;

g) copy of the remote pilot(s) licence;

h) copy of the aircraft radio station licence, if applicable;

i) description of the intended operation (to include type of operation or purpose), flight rules, visual line-of-sight (VLOS) operation if applicable, date of intended flight(s), point of departure, destination, cruising speed(s), cruising level(s), route to be followed, duration/frequency of flight;

j) take-off and landing requirements;

k) RPA performance characteristics, including:

1) operating speeds;

2) typical and maximum climb rates;

3) typical and maximum descent rates;

4) typical and maximum turn rates;

5) other relevant performance data (e.g. limitations regarding wind, icing, precipitation); and

6) maximum aircraft endurance;

l) communications, navigation and surveillance capabilities:

1) aeronautical safety communications frequencies and equipment, including:

i) ATC communications, including any alternate means of communication;

ii) command and control links (C2) including performance parameters and designated operational coverage area;

iii) communications between remote pilot and RPA observer, if applicable;

2) navigation equipment; and

3) surveillance equipment (e.g. SSR transponder, ADS-B out);

m) detect and avoid capabilities;

n) emergency procedures, including:

1) communications failure with ATC;

2) C2 failure; and

3) remote pilot/RPA observer communications failure, if applicable;

o) number and location of remote pilot stations as well as handover procedures between remote pilot stations, if applicable;

p) document attesting noise certification that is consistent with the provisions of Annex 16, Volume 1, if applicable;

q) confirmation of compliance with national security standards in a manner that is consistent with the provisions of Annex 17, to include security measures relevant to the RPAS operation, as appropriate;

r) payload information/description; and

s) proof of adequate insurance/liability coverage.

3.3 When certificates or other documents identified in 3.2 above are issued in a language other than English, an English translation shall be included.

3.4 After authorization has been obtained from the appropriate State(s), air traffic services notification and coordination shall be completed in accordance with the requirements of the State(s).

Note.-A request for authorization does not satisfy the requirement to file a flight plan with the air traffic services units.

3.5 Changes to the authorization shall be submitted for consideration to the appropriate State(s). If the changes are approved, all affected authorities shall be notified by the operator.

3.6 In the event of a flight cancellation the operator or remote pilot shall notify all appropriate authorities as soon as possible.

6.3.2  It is now up to the States to decide whether to transpose this rules or not in their own “ad-hoc” rules (any difference from ICAO Standard or Recomended Practice shall be addressed from the member state as stated on article 38 of Chicago Convention).

6.3.3  ICAO Aviation System Block Upgrade (ASBU) is a framework of block modules which is intended to enhance step by step, several aspects of the ATM world. Blocks B1-90, B2-90 and B3-90 are the steps which has been created to bring UASs into operational non-segregated airspace.

6.3.4  ICAO statement about financial implication on the ASBU-RPAS working paper for the twelfth Air Navigation Conference is:

“although cost to State associated with implementing new RPAS regulations based on ICAO provisions should be comparable to the cost for any other regulation, any delay in developing such provisions could lead to the implementation of a variety of interim, non-harmonized national provisions, with subsequent compliance issues. In this case the costs for industry could be much higher than necessary”.

As it can be seen, ICAO is affected by industry issue. Cost index, cost effectiveness and business based aspects are becoming even more relevant in the ICAO policies.

6.3.5  Among other issues, ASBU considers also the possibility of implementing airports that would support RPA operations only. It makes also some considerations about the expected mixed mode operations.

According to the working paper, ASBU should include:

“…adjustments to operational procedures for manned aircraft, ATC procedures and phraseology and aerodrome markings in order to safely and efficiently accommodate mixed operations.”

As we can figure out, ICAO’s think tanks are about mixed mode operations most probably won’t be dodged.

6.3.6  Amendment 43 to Annex 2 states that a legal person shall file an application each time an UAS wants to fly in non-segregated airspace. This legal person has to be a certified RPAS operator with licensed remote pilots and using certified RPAS.

The Amendment establishes that only the Remotely Piloted Aircraft (RPA: the flying part of the system), according to Article 31 of the Chicago Convention, needs an individual Certificate of Airworthiness and a registration. This leads to an important issue as it could bring to the opinion that ‘station’ will be a new ‘product’ shifting some responsibility from the State of Registry towards the State of Operator.

The amendment to ICAO Annex 2 may require an amendment to said Regulation, which currently considers the RPS a ‘part’ and not a ‘product’.

6.3.7  The UAS Study Group (UAS SG) is supporting ICAO on the development of a Manual, to be ready for the world-wide Symposium that is expected to be held in April 2014 which could be a starting point for new amendments to other Annexes to the Chicago Convention.

6.3.8  The remote pilots will use meteorological information, aeronautical charts and information as them can be found in ICAO Annexes 3, 4 and 15. The Unmanned Systems will use the same technologies as manned aircraft for communications with ATC (from the Air Traffic Services perspective) so that Unmanned Aircraft Systems are to be considered as one more airspace user which applies the same rules as any other. The Unmanned Aircraft Systems are moving from military operations to civil aviation. Some safety regulators have already published initial sets of rules or at least guidance material. As said above in 2013 an updated UAS Manual shall be published by ICAO while and a set of EASA rules should be issued in 2016.

The aviation regulations will slightly change in the future and probably in a rather quick pace.

6.3.9  During ICAO UASSG (UAS Study Group) and ASTAF meetings it resulted evident that See and Avoid cannot fully work for non-manned aircraft – even with very sophisticated cameras, and it will never achieve the same degree of flexibility and the same level of safety. Worse even for the very complex priority rules for avoiding traffic visually, the so-called “Right-of-way” rules (avoiding traffic visually with no risk of collision):

Annex 2 §3.2.2 “Right-of-way”

The aircraft that has the right-of-way shall maintain its heading and speed.

3.2.2.1 An aircraft that is obliged by the following rules to keep out of the way of another shall avoid passing over, under or in front of the other, unless it passes well clear and takes into account the effect of aircraft wake turbulence.

3.2.2.2 Approaching head-on. When two aircraft are approaching head-on or approximately so and there is danger of collision, each shall alter its heading to the right.

3.2.2.3 Converging. When two aircraft are converging at approximately the same level, the aircraft that has the other on its right shall give way, except as follows:

a) power-driven heavier-than-air aircraft shall give way to airships, gliders and balloons;

b) airships shall give way to gliders and balloons;

c) gliders shall give way to balloons;

d) power-driven aircraft shall give way to aircraft which are seen to be towing other aircraft or objects.

3.2.2.4 Overtaking. An overtaking aircraft is an aircraft that approaches another from the rear on a line forming an angle of less than 70 degrees with the plane of symmetry of the latter, i.e. is in such a position with reference to the other aircraft that at night it should be unable to see either of the aircraft’s left (port) or right (starboard) navigation lights. An aircraft that is being overtaken has the right-of-way and the overtaking aircraft, whether climbing, descending or in horizontal flight, shall keep out of the way of the other aircraft by altering its heading to the right, and no subsequent change in the relative positions of the two aircraft shall absolve the overtaking aircraft from this obligation until it is entirely past and clear.


6.4 Upcoming aspects

6.4.1  On May 2nd 2012 the Centro Alti Studi della Difesa (CASD – High level Defence Study Centre) of Rome (Italy) hosted a conference regarding the ethical aspects on the use of Remotely Piloted Systems. The debate touched less on the ethical and more on operational, technical and industrial aspects. Since the very beginning of this conference the CASD Chairman, Gen. Panato and the Chief of Staff of Air Force Gen. Bernardis highlighted that, despite mass media show UASs as a cynical mean of destruction at distance, there is no differences with intercontinental ballistic missiles with nuclear warheads or even as the simplest battle fought with bows and arrows that centuries ago opened an extensive debate on gallant rules in war (as a matter of fact, remote pilot can hit targets while being protected by familiar environment, relaxing after any working shift but getting the risk that the awareness on the events could go down to undesireable level).

6.4.2  More interesting in the debate were medical/psychological aspects of piloting in a remotely manner that take in count the risk that situational awareness may be less than piloting an aircraft being on-board of it. The challenge can become greater if we consider that by 2012 USAF will start operations where one remote pilot will manage 4 UASs at once. It is expected that these clues will affect civil UASs as well.

Other interesting issues are the technological aspects that highlights how many industries, like Agusta-Westland and Alenia, are elaborating even more advanced UAS concepts with an upgrading autonomy level (meaning with this the capability to be autonomous in decision making from humans). There are ten levels or steps that lead this systems to the complete autonomy even if it is still far to be carried out since nowadays we can only talk about “automation”. The human is still the core of the system (“man in the loop”) (A 24 hours operation with a Predator requires 110 operators and this is one of the reasons why industries are pushing the system to go from automation to decisional autonomy).

6.4.3  How will all these researches affect ATM world? Here we find the definition of “detect and avoid” again. Alenia and other aviation makes are developing the evolution of such concept, called “sense and avoid” by the industry, in which several sensors and apparatus (IR, TV, ACAS etc.) sends their readings to a central system that decides the most appropriate avoiding action.

6.4.4 EDA (European Defence Agency) is the contracting authority for MIDCAS (MID air Collision Avoidance System). This project has a budget of €50 million and is carried out by several industries: Alenia, Saab, Thales, Selex and others. It is developing an avoidance system for both military and civil purposes according to the following policy:

“The MIDCAS mission is to demonstrate the baseline of solutions for the Unmanned Aircraft System (UAS) Midair Collision Avoidance Function (including separation), acceptable by the manned aviation community and being compatible with UAS operations in non-segregated airspace by 2015”.

Since industry is worried about the increasing workload felt by remote pilots, it has already developed UASs which are capable of operating completely autonomous in some phases of the flight (by the time only take off, landing and obstacle avoidance). Industries will continue on switching to be autonomous even more and more aspect of the UAS flight (e.g. it is intended to be developed an “ethical code software” for military purposes) (programming code software which includes e.g. Geneva Convention rules, international rules of engagement, etc.).

The following chart shows the ten steps which should bring UASs to full autonomy:

6.4.5  Legal aspects analysis

6.4.6  In article 8 of the 1944 Chicago Convention on Civil Aviation is mentioned that:

“No aircraft capable of being flown without a pilot shall be flown without a pilot over the territory of a contracting State without special authorization by that State and in accordance with the terms of such authorization…”

While the Global Air Traffic Management Operational Concept (Doc 9854), confirms Article 8 and states:

“An unmanned aerial vehicle is a pilotless aircraft, in the sense of Article 8 of the Convention on International Civil Aviation, which is flown without a pilot-in-command on-board and is either remotely and fully controlled from another place (ground, another aircraft, space) or programmed and fully autonomous.”

Even then, a common intent was to state that a remotely piloted mean could not overfly a nation if the remote pilot is located in a nation which is not the one that is being overflown, unless a specific prior agreement has not been set between the affected nations. The event of a serious incident, or even an accident, under which national law will be judged? And any ATM related event? What about unlawful interferences then?

6.4.7  Nowadays an aircraft can be considered as a “closed system”: flight controls are directly linked to the pilot who is inside the airplane and therefore anyone who has the intent to hijack the plane should be inside the aircraft itself.

An UAS is an “open system” instead. Anyone who has the capability to intercept the communication between the remote pilot and the aircraft could take control of it.

Recently, a State declared that it had just hacked a NATO drone, landing it on its territory and then showing it off to the international media as a winning trophy. Press made no other declarations or comments and therefore it cannot be determined if those news were true or false. The assumption is anyway realistic.

6.4.8  Professor Todd Humphreys and his team at the University of Texas at Austin’s Radionavigation Laboratory recently completed a successful experiment: “spoofing” a small drone by jamming the GPS waypoints programmed in the UAS flight path.

Fox News released an article releasing that this experiment is:

“illuminating a gaping hole in the government’s plan to open US airspace to thousands of drones. They could be turned into weapons. In other words, with the right equipment, anyone can take control of a GPS-guided drone and make it do anything they want it to”.

The same article added then Professor Humphreys sentence:

“Spoofing a GPS receiver on a UAS is just another way of hijacking a plane”.

6.4.9  One of industries’ objective will be to make UASs control transmissions the more secure as possible. ATM system shall then consider such an event in which a hijacker will take control of an UAS being quietly seated on his chair in front of a computer. ICAO should so provide for this hypothesis and then rule UASs activities according to these aspects.

ICAO requirements from last stated policy doesn’t include a policy on C2 transmission that should be mandatory to be the most reliable and unassailable as possible. Otherwise a new kind of procedure must take in consideration the event of UASs hacking.


6.5 EUROCAE workshop

6.5.1 EUROCAE within the European UAS expert group, WG-73 is working with EASA in the development of airworthiness criteria and Special Conditions to supplement EASA A-NPA-16 Policy for Unmanned Aerial Vehicle (UAV) Certification.

Within this WG several work packages are being developed to study different features and issues about UASs including one of the most important, the WP 3.5 named “UAS Data Link Security”. According to EUROCAE policy, the requirements for communication, command & control (C2) systems will include autonomous operation to raise the security level. As we’ve seen previously, the possibility of the system hacking is realistic. Among others, these are some issues that could mostly affect ATM system that are being studied by WG-73:

  • There can be a trade-off between the capacity of the flight control data link and the autonomous capability of the UA.
  • Security of the Command and Control link is considered mandatory (equivalent to locked cockpit door).
  • Means of communication and phraseology will need to be compatible with the applicable ATC environment.
  • Issues include:
    • The degree of autonomy of the UA;
    • Compatibility with the evolving ATM;
    • The capacity, integrity, redundancy and security of flight control data links;
    • Control station: human-machine interface, security measures;
    • Data synchronization at control station handover; (normal and abnormal conditions);
    • Support tools for mission planning; and personnel training and qualification.

The operational robustness of dedicated security measures for the link, and the impact on required frequency bandwidth is a fundamental milestone.


6.6 EASA Policy

6.6.1  EASA is working on airworthiness certification of UASs and the Agency’s objectives as on DOC E.Y01301 are:

“The overall objective of this policy is to facilitate acceptance of UAS civil airworthiness applications, while upholding the Agency’s principle objective of establishing and maintaining a high uniform level of civil aviation safety in Europe together with the additional objectives stated in Article 2 of the Basic Regulation.

4.1 Airworthiness objective

With no persons onboard the aircraft, the airworthiness objective is primarily targeted at the protection of people and property on the ground. A civil UAS must not increase the risk to people or property on the ground compared with manned aircraft of equivalent category.
Airworthiness standards should be set to be no less demanding than those currently applied to comparable manned aircraft nor should they penalise UAS by requiring compliance with higher standards simply because technology permits.”

Note: The protection of other airspace users is dependent on ATC/ATM separation procedures and defined “detect and avoid” criteria, commensurate to the airspace class and type of operations (i.e. within or beyond visual line of sight). These aspects are considered outside of airworthiness. However, there will be an airworthiness function to verify that equipment designed to meet such criteria, together with the unmanned aircraft’s performance, are satisfactory.

6.6.2  EASA will consider the “detect and avoid” feature of an UAS as something which is outside the definition of airworthiness. What’s our understanding is that the Agency’s intention is to consider those issues as part of the ATM rulemaking options and to transfer it to ICAO or to each Member State ATM regulator.

6.6.3  The Agency’s rulemaking responsibility is limited to certain UAS types. Unmanned aircraft excluded is identified as follows:

“Article 1(2) … [Those] engaged in military, customs, police or similar services. The Member States shall undertake to ensure that such services have due regard as far as is practical to the objectives of this Regulation.

Annex II (b) aircraft [of any mass] specifically designed or modified for research, experimental or scientific purposes, and likely to be produced in very limited numbers.

Annex II (d) aircraft that have been in the service of military forces, unless the aircraft is of a type for which a design standard has been adopted by the Agency.

Annex II (i) unmanned aircraft with an operating mass of no more than 150 kg.”

EASA intentions is that the safety oversight of any UAS type that has been excluded by the Basic Regulation is the responsibility of the Member States.

6.6.4  Some specific features make an UAS a unique type of aircraft. These has been named as Special Conditions (SC) and are given as follows:

  • Emergency Recovery Capability
  • Command and Control Link
  • Level of Autonomy
  • Human Machine Interface
  • Control station
  • Due to type of operation
  • System Safety Assessment

6.6.5  In its policy document EASA stated the need for security requirements even if it’s outside the Agency regulatory framework. Once again the failure event of the encryption used for C2 systems is considered a primary issue:

“Although security is seen as a key issue for UAS, the Agency is not in a position to mandate security requirements since security is clearly outside the Agency’s competences established by the Basic Regulation. However if security systems are mandated by the appropriate authority or installed voluntarily, they should not impact safety. For example some failure cases of encryption devices could impact control commands.”

6.6.6  A set of EASA rules for UAS is foreseen for 2016.


6.7 SIGAT project

6.7.1  European Defense Agency (EDA) has created the SIGAT project – Study on the Insertion of UAS in the General Air Traffic, a consortium of EADS, Sagem, BAE and Dassault. Once again industry is involved (and maybe leading) in the studies about this matter.

SIGAT statement is as follow:

“Now that UAS have proven their advantages for many applications, the next major milestone will be the ability for UAS to share civil airspace with other aircraft in General Air Traffic (GAT), instead of being restricted to segregated airspaces as today. UAS development promises to take off once this capability is ensured.

To this end, a major challenge is to ensure UAS safety of flight for other airspace users at the level of international civil aviation. Given that UAS are remotely piloted through a Command & Control (C2) radio-frequency data-link and use a Sense & Avoid (SAA) system for anti-collision purposes, there is a need for a specific spectrum allocation consistent with such safety requirements. C2 spectrum is needed for Line of Sight (LOS) communications and for BLOS (Beyond Line of Sight), also called SAT (Satellite) communication.”

6.7.2  The existing satellite communication technology is not as reliable as it is expected for General Air Traffic purposes.

The option 1 for Line Of Sight (LOS) operations using satellite communication is to use existing civil aviation bands and fly GAT. This option is the nominal solution that complies with ICAO safety of flight requirements and the use of specific aeronautic frequency bands. Current satellite constellations do not offer sufficient C2 Beyond Line Of Sight (BLOS) capacity today. Additional satellite capacity is needed.

The use of commercial satellite bands to fly GAT (option 2) would use non-aeronautical bands and doesn’t comply with ICAO safety of flight requirements. This solution benefits from existing satellite constellations, such as TV broadcast services but as significant drawback to this solution is the fact that ICAO strongly opposes to this alternative today.

Another option (3) is to turn a portion of existing commercial satellite band into an aeronautic band and fly GAT. This alternative combines the use of existing satellite constellations with the safety of flight requirements of specific aeronautic bands. The drawback of this option is the predictable opposition of commercial operators that must release part of their spectrum.

Last option (4) would use existing satellite bands and fly OAT. This alternative complies with ICAO requirements and benefits from existing Satellite constellations. The main advantage is that this option is straightforward and can be used at short term. One disadvantage is the lack of OAT harmonisation between countries, raising some complexity for international cross-border flights.

6.7.3 SIGAT recommendations depend on which options are chosen:

  • Support the World Radiocommunication Conference 2012 (WRC-12) in provisioning specific aeronautic bands complying with ICAO Safety of flight requirements.
  • Take urgent decision on option 3 suitability.
  • Support Eurocontrol (or other) efforts to harmonise OAT (option 4).
  • Decide how to convince ICAO to change its safety requirement in case of option 2.

6.8 NASA’s NAS UAS Access Project

6.8.1  In 2011 in USA over 600,000 hours of flight has been collected by UASs. NextGen program, FAA and NASA have included an integration process for UASs in non- segregated airspaces. The UAS Integration in the National Airspace System (NAS) Project has been created by NASA’s Aeronautics Research Mission Directorate (ARMD) to study the way to integrate UASs into non segregated airspaces. It received funding of about $150M over the last 5 years. This committee is working jointly with FAA’s Unmanned Aircraft Program Office (UAPO) and with RTCA Special Committee 203 (SC-203).

6.8.2  The technical challenges and issues which came out from this projects are similar to those studied in Europe:

  • Lack of validated technologies and procedures for UAS to separate itself from other aircraft and to operate within NAS and NextGen Air Traffic Services;
  • Lack of minimum system and operational performance standards and certification requirements;
  • Lack of relevant test environment for validating concepts and Separation Assurance/Sense and Avoid Interoperability (SSI).

The SSI subproject will measure the impact of this increase on the air traffic control system’s ability to ensure separation for several future UAS integration scenarios, both under today’s operations and in NextGen.

6.8.3 The US Code of Federal Regulations (CFR) clearly defines the legal framework for pilots on “see and avoid” operations. Future Sense and Avoid (SAA) systems will provide operators with some level of surveillance information about aircraft near the unmanned aircraft and, as for TCAS, NASA expect to see operators manoeuvring the UAS to avoid other aircraft without ATC coordination. Simulation flights will take place in 2015 and 2016.

6.8.4 NASA is also developing the Human Systems Integration (HSI), a research test-bed and database to provide data and proof of concept for Ground Control Station (GCS) operations. NASA is deeply involved in UAS certification and communication issues. Analysis and recommendations for securing civil C2 systems, and will support the United States’ efforts to obtain additional BLOS UAS spectrum at the 2015 World Radiocommunication Conference.

All this issues and developments will be tested in the Integrated Test and Evaluation (IT&E) which will include all the technologies developed within the SSI, HSI and Communications sub-projects through a series of fast time simulations, high-fidelity human-in the-loop simulations, and integrated flight tests in a relevant environment.


6.9 FAA Mid-air Collision Hazard studies

6.9.1 The American Institute of Aeronautics and Astronautics has developed a model of mid-air collisions between UASs and other aircraft which takes into consideration various aspects like air traffic density data from the FAA to determine the expected number of collisions per hour. The target level of safety for the mid-air collision hazard from FAA safety guidelines for manned aircraft, is 10 ^ -9.

The analysis provides insight into the variation of collision risk with respect to structure of the NAS and the possibility of low-risk operating strategies and requirements for mitigation. The potential for mid-air collision between a UAS and several other aircraft was modelled based on a gas model of aircraft collisions. In this model, the UAS is equally likely to be located anywhere in the volume of airspace under investigation. The expected level of safety in terms of potential collisions per hour of UAS operation is then the ratio of volume extruded by threatened aircraft per hour to the volume of airspace.

For the preliminary analysis the area of exposure was estimated as the frontal area of a Boeing 757, approximately 560 ft. The area of exposure also did not vary significantly with UAS classification, assuming the UAS area is smaller than the threatened aircraft.

UASs need to reach a mean time between failures of 100 hours to meet a target level of safety 1 x 10 ^ -8 fatalities per hour. More mathematical models and equation are not explained in this working paper but the results of them. The reliability is already within the requirements demonstrated by several current UASs. To satisfy mid-air collision safety requirements an active mitigation measures could include using frangible UASs that impart less damage to other aircraft and being equivalent to a bird strike.

6.9.2 Significant mitigation would be required to operate bigger drones like High Altitude and Long Endurance (HALE) UAS. High altitude UASs pose greater risk than other classes so they will need to incorporate more sophisticated mitigation measures to prevent mid-air collisions such as “sense and avoid” systems, or active air traffic control separation, which are all items under construction.

This study recognized how a significant increase of UAS operations are expected to emerge in the future. The type and magnitude of mitigation employed to meet system safety standards will vary significantly between classes of UASs.

It also showed what are the collision hazards on UASs operations but considering collision event only. New studies are required to consider the ICAO separation minima and the related airspace infringement case.


6.10 Single Sky Committee and the European Strategy in support of the UAS sector

6.10.1  After recognizing the dramatic grow of military UAS operations and the possibility to mirror these activity in civil sector, the European Commission started a panel for the support of the introduction of UAS in the European airspace.

“…However, there are still barriers that limit the possibility for UAS to fly in non-segregated airspace. The growth of the UAS market on the global scene should be carefully considered and appropriate actions should be taken at the European level to promote the development of the European UAS sector.”

(European Commission SSC/12/46/18 Agenda Item 11.1 – 31 May 2012)

6.10.2  After some preliminary hearings about light UAS activity, the Commission decided in 2012 to launch the “UAS panel initiative” with the aim of supporting the industrial and customer needs to develop a European UAS market. Many different initiatives showed a fragmented scenario with no common approach under Europan objective to support this sector. The need to clearly identify the barriers that limited a true industrial improvement on civil development was found.

On June 23rd 2011 at the Paris International Air Show, the Commission launched a new initiative, called “UAS Panel”, aimed at providing the strategy for the development of UAS in the EU. This initiative was opened to all relevant stakeholders: Eurocontrol, the European Civil Aviation Council/ECAC, the European Aviation Safety Agency (EASA), the scientific community, ECAC, ICAO, JARUS, Ministries of the Internal Affairs (border surveillance, police forces), the European Defense Agency, Ministries of Defense, the European Space Agency (ESA), international military organizations, non-governmental organizations, international stakeholders, European citizens and a broad industry representation from SMEs to global players which manufacture and/or operate UAS.

6.10.3  The workshops allowed a wide consultation of all stakeholders on the following topics:

  • RPAS Industry and Market
  • RPAS insertion into airspace and radio frequencies
  • Safety of RPAS
  • Societal dimension of RPAS
  • Research and development for RPAS

6.10.4  The conclusions of these debates produced the document, entitled “Towards the Development of Civil Applications of Unmanned Aircraft Systems (UAS), a Strategy for the European Union”, that was presented to the UAS panel on May the 2nd 2012 meeting. This document concludes that in order to promote the RPAS market and its many applications, a European initiative led by the Commission would be necessary.

This initiative would be implemented under the “European RPAS Steering Group (ERSG)” which will develop a comprehensive Roadmap for RPAS. The Staff Working Paper foresees the completion of the Roadmap in the first quarter of 2013 and proposes that the initial insertion of RPAS in non-segregated airspace would be achieved in 2016.

These deadlines take account of the recent announcement by the US to mandate the FAA to prepare for the RPAS’ insertion in the national airspace in 2015.


6.11 Final Thoughts

6.11.1  IFATCA’s aim is to obtain that every aircraft flying in a determined airspace is compliant with ICAO requirements, even it is manned or not. Whenever manned and unmanned planes are considered simply as “aircraft” without differentiation if any of them will be fully compliant or not with any ICAO requirements, it will be meaningless to know if there is a pilot on-board or not.

This won’t make any difference by a controller’s point of view. It should be even better not to know if he cockpit is “inhabited” or not. This would not differentiate the awareness related to the different type of aircraft, would make the operations more reliable and would avoid mixed-mode. Unfortunately this seems to be not the same intent of the other members of the aviation world.

6.11.2  Industry is pushing to bring UASs into the same airspace used by manned flights but using different capabilities. Studies on UASs integration into non-segregated airspace have already started. Are we on the threshold of a revolution as it was for internet? Perhaps yes; Internet as well was developed from a military project (ARPANET) to be converted in civil purposes and providing us the services we all know today. The increasing activity at industry level show us that the interest on UASs is at the maximum level and that many projects are on the way.

6.11.3  The Japanese earthquake of Tohoku (march 11th 2011) has been the operational field of several UASs which monitored Fukushima’s nuclear plant that, after its explosion, presented a level of radioactivity that was too high for human beings.

New concepts of UASs are in the development phase: territory recognition, environment watch, high level risk area intervention (fire, contaminated areas…), for recreational use (advertising using giant monitors on airships) or even for postal services (will we see unmanned B747 Cargo?).

It was not mentioned on the passenger transport since this argument is still facing an unenthusiastic public perception. It’s anyway well known how industries can force mass media to change public opinion and therefore, we have to expect new development in this topic.

6.11.4  Automation is rapidly changing the cockpits. Flight engineers were replaced almost 30 years ago. Then was the time of many instruments that, being assumed as indicators of simple “housekeeping tasks” have been moved to on-board computers. Today’s glass cockpit should be the last step into unmanned cockpit. Future scenarios foresee autonomous machines.

It is anyway expected that at least till 2030 men will remain “in the loop”. We have seen that industries are trying to overdrive the ATM system that, due to all its rules, is seen as a limit to the development of more efficient way of flying.

Air traffic controllers shall show that they are not against new technology nor economy, but that any new concept must first of all take into consideration all the safety aspects and that the responsibility and liability framework between humans and machines must be clearly defined.

Last Update: September 30, 2020  

June 19, 2020   373   Jean-Francois Lepage    2013    

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