Small World

Gary Church outlines the Small Unmanned Aircraft Systems (UAS) Rule the US Federal Aviation Administration (FAA) should write.

The last five years have seen an explosion of issues and concerns associated with the growing production and use of small unmanned aircraft and systems.

New and emerging “drone” technologies have ushered in applications for small unmanned aircraft systems (UAS) that continue to challenge traditional aviation regulatory paradigms.

Until recently the FAA was comfortable with an Advisory Circular issued on June 9, 1981 (AC 91-57) to provide operational guidance to operators of model aircraft.

However, the rapid development and high profile operations of small UAS has disrupted this peaceful state of affairs and thrown the FAA into a full forward press first to provide policy guidance then to propose regulations to address UAS safety concerns for human injury and property damage both in the air and on the ground.

In the last 24 months a number of lawsuits and administrative actions have begun to challenge FAA’s UAS policies. There is no doubt these challenges will continue well after FAA rules are finally issued in an attempt to clarify and perhaps restrict the government’s regulatory authority.

Contentious issues in regard to UAS will extend to many federal agencies beyond the FAA, from the Department of Homeland Security to the Environmental Protection Agency, the Department of the Interior and the Department of Agriculture.

Privacy and property rights issues will continue to develop as public concerns as local, state and Federal agencies begin to use UAS for regulatory survey and enforcement. While there is extensive case law addressing privacy and property rights, there are as yet no UAS precedents.

While there are local, state and federal laws that address many public concerns such as public endangerment and unauthorised surveillance, UAS will challenge the context of many of them.

Ultimately it will be the courts and the US Congress that will have to provide the clarity needed to fully integrate UAS productively into our lives. This will no doubt be a long and arduous process. The near term challenge to the FAA is to promulgate flexible UAS rules that are clear and concise, that can be complied with reason, and that can be effectively enforced.

As FAA UAS rulemaking moves forward there appear to be a number of key provisions identified in UAS related advisory and regulatory actions from countries such as Canada and Australia.

These provisions provide guidance that emphasizes the need to ensure FAA regulations support safety in terms of reasonable and acceptable levels of aviation associated risk and at the same time be flexible and permissive enough to allow a nascent new industry and aviation business model to grow and prosper.


There is no need to reiterate the significant number of social and economic benefits that can accrue from the responsible use of UAS. The applications run a gamut of purpose where costs, speed, mobility and agility are high priorities in placing sensors or stores with precision.

In many cases these missions use a UAS as a delivery platform to do what is dirty, dull or dangerous for humans or to simply accomplish long duration missions without attempting to accommodate increased size, weight and complexity needed to meet the physiological needs of a human.


Ever accelerating technological advancements in UAS airframes, powerplants, sensors, command and control systems, and data processing capabilities have demonstrated the amazing fast-paced innovation that has been applied to create rapidly emerging UAS social and economic benefits.

Operating in Proximity to Airports Many of these innovative technologies can address broader aviation safety concerns. For example, ubiquitous GPS positioning can easily provide geo-fencing to identify and limit small UAS operations from designated distances from airports. This capability coupled with the ability to use altimetry to limit small UAS altitudes can comply with current FAA airspace regulations and no doubt mitigate unnecessary and overly restrictive regulatory requirements.

Importantly, with the knowledge of distance and direction from an airport runway, altitudes may be controlled so the nearer the runway the lower a small UAS can fly. This would allow small UAS to comply with Federal Aviation Regulations Part 77 to stay below the FAA’s obstruction notification height[1] and create a safe operating environment consistent with accepted FAA safety standards.

Operating Beyond Line of Sight The “killer” application for small UAS is the ability to operate beyond line of sight day or night. While the ability of an operator to see a small UAS with the “naked eye” is an important first step to ensure safety, the real social and economic benefits of small UAS reside in the continuing development of surveillance systems that effectively and safely extend the range of the human operator and observer beyond their line of sight.

For example, the US Department of Defense is in the midst of expanding its UAS detect and avoid surveillance network. At least two different surveillance radar architectures and systems are currently in use.

Commercial interests continue to invest, develop and test surveillance systems using a variety of sensors and technologies including small low cost and portable 3D primary radar, multi-lateration, electro-optical sensors, acoustic sensing and dual mode (1090 Extend Squitter and Universal Access Transceiver) Automatic Dependent Surveillance Broadcast (ADS-B). These systems are quickly approaching both performance and cost targets that make them viable for UAS surveillance applications.

There appears to be justifiable concerns that FAA small UAS regulations will prohibit the use of these beyond line of sight surveillance systems and future acceptance will entail either modifying the small UAS rule or going through an extensive, time consuming and expensive rule exemption process. One alternative is to apply administrative letter of relief provisions within the rule. For example, “Unless otherwise administratively approved by the Federal Aviation Administration, no person may….”

Operating with Automation The days of manually operating aircraft manned or unmanned are far behind the current state of the art. For example, the Department of Defense’s large Global Hawk UAS is a totally automated system[2]. These UAS are preprogrammed with a mission to be executed. The entire multiday mission can be flown without pilot commands, although the pilot may provide input, such as altimetry setting or air traffic control transponder codes.

Additionally the pilot has the ability to override the automated systems to command the UAS to fly a different flight profile. In this case the pilot is said to be “on-the-loop” as opposed to “in-the loop”. “In-the-loop” means the vehicle would be commanded to manoeuvre by and through the pilot.

The rapid development of automated systems for UAS opens up capabilities far beyond those that rely upon a pilot to directly command the vehicle. The ability to monitor and quickly react to a variety of conditions and circumstances means an automated UAS can execute programmed contingencies and effectively fly to or hold position and change or hold altitude in changing environmental conditions better and faster than a human operator can recognize and react to them.

This applies to the organisation and operation of multiple vehicles that can considerably expand and extend UAS benefits. Collision avoidance is a prime example of leveraging the precision and responsiveness of an automated system that has a pilot “on-the-loop”.

The viable and successful commercial development and deployment of small UAS will be dependent upon the technologies discussed above. FAA rules that inhibit or restrict these technologies will significantly alter the realisation of promised benefits of the small UAS.


Although the FAA has an extensive aviation education and outreach programme ( little if any institutionalised efforts have been made to reach the hundreds of new and established small UAS manufacturers or suppliers or the tens of thousands of small UAS operators. Many believe that small UAS incidents are due to a lack or knowledge and understanding of established safety rules as opposed to any malicious intent. The FAA’s approach should initially be to educate and not to establish rules and means or methods to meter out punishment.

Working closely with manufacturers could encourage and assist them in developing and implementing technologies that codify rules and best practices within small UAS command and control systems as previously discussed. Also, the FAA could work with manufacturers and operator groups to develop educational materials to be included in small UAS point of sale packaging. Ultimately these efforts may be more productive and cost effective than efforts to enforce unnecessary and overly restrictive and punitive rules.


The UAS developments of the last few years have established trends that need to be recognized by regulations. There has been and remains a strong toy industry for all types of aircraft, including what the FAA now classifies as UAS, which supports and encourages a child’s fascination and love for aviation. Secondly, there is a strong interest by adults in operating small-unmanned aircraft for recreational use such as photography. Lastly there are the small-unmanned aircraft system operators that see tremendous commercial opportunities with small-unmanned aircraft systems that run a gamut of applications.

Toys In recognition of the very small unmanned aircraft systems that can be thought of as toys a number of countries, including Australia[3] and Canada[4], proposed or adopted a weight limit of less than 2 kilograms or 4.4 pounds that do not require operator certification or vehicle registration for the use of these very small unmanned aircraft systems, albeit there are operating rules and guidelines as discussed below that apply to their use.

Recreational Recreational UAS vehicles are those operated by hobbyists for non-commercial purposes, whether they are following the Model Aircraft provisions of the FAA Modernization and Reform Act of 2012 (P.L. 112-95, section 336) or not. This proposed class of vehicle weighs 2 kilogrammes (4.4 pounds) or more, but has a gross takeoff weight of less the 25 kilogrammes (55 pounds).

A simple Internet web based registration could be used to issue identification markings that can be inscribed on the vehicle for positive identification prior to flight. This fast, efficient and effective Internet type of registration is currently used by a number of Federal government agencies, including NOAA for user registration and re-registration of a 406 MHz Emergency Position Indicating Radio Beacon (EPIRB).

Commercial Commercial UAS vehicles are those operated that produce income or other tangible value. These vehicles have the same range of weight as a recreational UAS. The weight could encompass 2 kilograms (4.4 pounds) or more, but have a gross takeoff weight of less than 25 kilograms (55 pounds).

Commercial vehicles might have an Internet web based registration but this registration could and should be more detailed or involved than that required by recreational UAS. This is based on a recommended provision that a UAS used for commercial purposes shall meet ASTM Small UAS industry design and build standards, whereas compliance to these standards would be optional for recreational vehicles.

The rationale for this requirement is that commercial UAS are expected to have greater use in more demanding environments than recreational UAS and greater care is needed to ensure an acceptable level of aviation safety.


There is no question that some level of aeronautical orientation and training as well as some minimal skills are needed to safely operate a small UAS. The level of knowledge and skill should be proportional to an expected graduated risk (i.e., probability and consequence of failure) from children operating toys, to hobbyists to commercial operators. As acknowledged by Canada and Australia a key provision for any operator is that they are mentally and physically capable of safely operating a UAS.

Toys FAA should engage the toy industry with an outreach program of education so that adequate guidance materials for safe operation of a very light small UAS is provided with each small unmanned aircraft system. Public service campaigns should be part of this educational approach using all aspects of social media. Provisions of the rule should allow children under the age of 16[5] to operate this class of UAS under the supervision of an adult.

Recreational An operator 16 years of age or older of a recreational vehicle should receive a recreational small UAS operators certificate from the FAA. This certificate could be obtained by taking Internet web based training and passing an online test to immediately receive and print a certificate authorizing the certificate holder to operate a recreational UAS in compliance with operational restrictions.

Commercial The operator of a commercial small UAS should be 17 years of age or older and should receive an operators certificate from the FAA as well. Internet web based training and testing could be completed online. However, there is a greater depth and breath of knowledge that should be required for a commercial operator. Additionally, a commercial operator should be able to successfully demonstrate his/her skill to operate a small UAS prior to receiving a certificate. If successfully demonstrated the small commercial UAS could be operated in compliance with FAA standards for beyond line of sight (which includes night operations) and/or in compliance with other commercial capabilities, functions or features administratively approved by the FAA on a case-by-case basis.


Regardless of the class of a small UAS vehicle; toy, recreational or commercial the UAS should give right-of-way and remain safely well clear of all other airborne vehicles. Additionally, regardless of class of UAS vehicle, it should remain at least 100 feet, laterally or vertically, from any human not participating in its operation. Lastly, consistent with the Canadian UAS Advisory Circular AC600-004 to limit of the kinetic energy of a small UAS vehicle, its maximum speed should not exceed 87 knots (100 mph).

Toys The operation of very small UAS less than 2 kilograms (4.4 pounds) should be limited to altitudes below 500 feet above the ground and should remain clear (i.e., below) of Class A, B, C and D airspace as depicted on an FAA Aeronautical Sectional or Terminal Area Chart unless it is capable of remaining below the FAR Part 77 obstruction notification surface in proximity to a runway.

Further, it should be flown within the sight of the operator, even if an observer is present. Since the visibility range of a very small UAS is considerably less than one mile there should be no visibility or clearance from cloud requirements since the very small UAS would be required to remain in view of the operator at all times.

Recreational The operation of a small UAS 2 kilograms (4.4 pounds) to less than 25 kilograms (55 pounds) should be limited to altitudes below 500 feet above the ground and should remain clear (i.e., below) of Class A, B, C and D airspace as depicted on an FAA Aeronautical Sectional or Terminal Area Chart unless it is capable of remaining below the FAR Part 77 obstruction notification surface in proximity to a runway.

Further, it should be flown within sight of the operator, even if an observer is present. Since the human eye cannot resolve an object 3 feet in diameter beyond one-half mile under the best of conditions, there should be a visibility requirement of no more than one statute mile and simply a clear of cloud requirement consistent with FAR Part 91.155(b)[6] since the vehicle should be seen at all times by the operator.

Commercial The operation of a small UAS 2 kilograms (4.4 pounds) to less the 25 kilograms (55 pounds) should be limited to altitudes below 1,000 feet above the ground consistent with FAR Part 91.119[7] and should remain clear of Class A, B, C and D airspace as depicted on an FAA Aeronautical Sectional or Terminal Area Chart unless it is capable of remaining below the FAR Part 77 obstruction notification surface in proximity to a runway or unless operations are approved by air traffic control. A commercial UAS should be flown with constant pilot or observer surveillance using surveillance means and methods administratively approved by the FAA.


UAS, just like commercial space, represents a new business model that diverges from the seventy-five year old commercial air transport model upon which the FAA was built. Traditional paradigms, means and methods will not support the future needs of new entrants in achieving their potential for economic and social benefits.



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