What Does the Civilian RPA Industry Need from the Regulatory Authorities ?

The over-arching objective is to allow the UAS operators to carry out useful commercial, public, or research flights of remotely piloted aircraft (RPA), without undue risk to other airspace users and people on the ground. I think that this objective will have broad public support.

There is also an additional constraint that RPA shall not deny airspace to manned aircraft. This constraint is more questionable, and can be argued against, as will be explained in the following.

Essentially, all flying aircraft deny airspace to other aircraft, due to the need for adequate separation to prevent mid-air collisions. In controlled airspace, the typical minimum separation is 5 nautical miles horizontally and 1000 feet vertically. Thus, aircraft in controlled airspace carry along a rather big bubble of airspace which is denied to other airspace users. For flights in uncontrolled airspace, separation requirements are less, however Rules of the Air demand pilots to keep well clear of other aircraft.

The constraint should be modified to “no aircraft shall allocate more airspace than necessary to maintain adequate safety and to carry out its mission”. And the allocated (dedicated) airspace shall be kept to a minimum in time and space, utilizing all available means for a reliable separation of aircraft.

RPA should be recognized by authorities as having equal rights to airspace as manned aircraft. Airspace access should not be dependent on the Pilot-in-Command (PIC) being onboard or on the ground. In case of conflicts of interest (congestion of airspace), airspace access must be negotiated, and priority will typically be given to defence, police, and customs authorities, over commercial, scientific, and (eventually) recreational users, regardless of the location of the PIC.

For flights in controlled airspace (class A, B and C), where all aircraft are “visible” to ATC, the situation is relatively simple. RPA flying as controlled flights must have sufficient reliability to ensure that they will be capable of complying with ATC instructions, with a very small failure rate.

For flights in uncontrolled airspace (G class), the challenges are bigger. This airspace will typically encompass air from ground up to FL95 (ca 3000m above sea level), and away from controlled airports. In this airspace, pilots are legally allowed to fly their aircraft without radio, based on the see-and-be-seen and right-of-way principles of Rules of the Air.  However, what is legal is not safe. We know by experience (and accident statistics) the deficiencies of the see-and-be-seen principle. In particular, mixing of different types of aircraft (fighter aircraft, helicopters, G.A. aircraft, ultra-lights, gliders, hang-gliders, para-gliders, and parachute jumpers) in the same G-class airspace is dangerous. Adding various sizes and types of RPA into the mix will increase risk further. The larger and faster RPA will eventually have sense and avoid capability with predictable performance, which will probably enable them to operate in G-class airspace with less risk than manned aircraft (!). However, for the smaller and lighter RPA, a sense and avoid capability alone may not be very useful, because of their inability to escape from an intruder, and their low visual conspicuousness; thus radio communication systems (e.g. FLARM, ADS-B, and similar) currently seem to offer feasible means of providing separation.

At this point in time, the development of navigation and communication systems has provided us with the necessary technologies for self-separation of co-operative aircraft. This development is however not appreciated by governments, regulators, and Rules of the Air for uncontrolled airspace are still based on technologies and air traffic density of the years following World War 1. (*) It is now time to consider updating the rules and organization of uncontrolled airspace, to increase safety of manned aviation as far as achievable with available means, and allow RPA operations, safely. It is necessary that regulators accept, recommend, or even prescribe the use of aircraft-to-aircraft communication systems, which can enable pilots to efficiently detect and avoid other aircraft reliably. Furthermore, it is necessary to implement a system to efficiently reserve boxes of uncontrolled airspace to users who need to use it alone, or with regulated access by other aircraft, e.g. for military training flights, RPA flying survey grids, etc.   Such reservations shall need to be limited to the airspace and time required for safe execution of a mission. Furthermore, if it is safe, other aircraft may be allowed to fly through the airspace, if they fulfill given conditions, e.g. they are equipped with necessary aircraft-to-aircraft communication systems, and coordinate their flight with the aircraft operators who have reserved the airspace.

In legal terms, this means establishing an efficient system for allocating danger areas, and making these known to all airspace users in an efficient way (daily updating on moving map navigation systems with airspace access restrictions from ATCC database). This concept would expand the flexible use of airspace (FUA) concept from controlled airspace into uncontrolled airspace, to the benefit of all airspace users (manned and unmanned), maximizing availability of airspace as far as possible as safety is maintained.

(*) History: The first attempts to provide a function of air traffic control were based on simple “rules of the road” (European sponsored International Convention for Air Navigation, 1919). The first air traffic rules were established in the United States by the passage of the Air Commerce Act in 1926.

[ Per Osen is an independent consultant based in Norway – posen@online.no – Ed.]