Aircraft Accidents and UAS Data, Part Five

Beginning in November 2016, with Aircraft Accidents and UAS Data, Parts One and Two; then in October 2018 with Aircraft Accidents and UAS Data, Parts Three and Four; I tried to make use of valuable research into the safety aspects of the Unmanned Aircraft System (UAS) vehicles as reported by the Authors: Ryan Wallace, Kristine Kiernan and John Robbins, all of Embry Riddle Aeronautical University and their colleague, Tom Haritos of Kansas State University. Their third Article, titled: Small Unmanned Aircraft System Operator Compliance with Visual Line of Sight Requirements, was printed in the International Journal of Aviation, Aeronautics and Aerospace, Volume 6, Issue 2 in 2019.

To summarize, the first Article dealt with a series of controlled tests that determined if pilots could see, with the naked eye, an unmanned aerial vehicle (UAV) in their flight domain (X, Y and Z axes), even when the test pilots knew the UAV was there. The second article dealt with overseeing different UAVs operating around a commercial airport’s airspace using the latest technology.

The Authors are professionally supportive of UAS success, both in a commercial venue and as recreational devices for, e.g. hobbyists. The Authors are, as demonstrated by their research, dedicated to safety, not only to the UAV operator, but to all the aviation community that UAVs interact with. And that’s the rub: those invested in UAS as commercial entrepreneurs are committed to safety, to expanding their businesses as a benefit, not a hazard. Can the same be said for all UAV operators?

The third Article begins by examining an accident – not incident – involving a small UAS (sUAS) operator and a military helicopter. The September 21, 2017 event involved a DJI Phantom 4 UAV being flown in the evening from as far away as 2.5 miles from the operator, “well beyond visual line of sight (BVLOS)”. The operator flew the UAV solely with a user interface map – no visual contact – into one of a UH-60M military helicopter’s rotor blades. The speed with which a flying helicopter’s rotor blades turn spells disaster when they hit a comparatively stationary object; the damaged blade(s) causes an imbalance in the rotor system, control issues and a loss of lift. The danger exists to the flight crew, anyone flying nearby (‘wing’ man) and anyone on the ground within the crash circle of the falling helicopter. If the out-of-control helicopter happens to be over a city? Numerous fatalities!

The article’s Problem statement: “The potential hazards associated with BVLOS flight represent a clear danger to manned aircraft operators and other National Airspace System (NAS) users. Currently, no data exists to accurately assess the distance at which sUAS operators are flying their aerial vehicles. The authors sought to determine … appropriate waivers or risk mitigation.” A telling Problem statement, especially if one understands the implications. Why is it that “no data exists” in a time when military UAVs could be controlled from across the world for decades?

According to, miniature and micro UAVs have been around since 1990. Remote control aircraft have been around longer, according to, since at least 1985. The technology for controlling a UAV remotely has moved from line of sight to miles from the operator. Why did it take thirty-one years (2016) for industry and the Federal Aviation Administration (FAA) to publish rules for safe UAV operation, e.g. training or operation requirements? Why has it taken thirty-four years for studies to be published that examine the real risks of introducing UAVs into the NAS?

The article’s Purpose statement: “The Purpose of this study was to assess sUAS operator practices with an emphasis on the range and visibility characteristics between the operator and aerial vehicle. This data will be used to establish a baseline of UAS operator flight behavior as well as generate UAS policy and safety recommendations.”

The Purpose statement is also revealing; not just the third Article by itself, but when combined with the first two. These Articles are not anti-UAS; they are anti-complacency. The aviation industry has ignored the UAS industry; UAVs have obviously evolved to the point of major concern. At this time, the aviation industry cannot be proactive, but instead, as always, are reactive. The UAS industry has never been the problem; it was the ‘we’ll-deal-with-it-later’ attitude that has the aviation industry behind the eight ball.

The article utilizes several methodologies to determine operator-to-UAV visual detection efficiency of, e.g. BVLOS and hazards. The Authors state under Hazards of BVLOS Flight that, per a study by Terwilliger in 2012, “Flights beyond visual line of sight have the potential to be particularly hazardous, since they limit the situational awareness of operators. Known as the soda straw effect, the reduced field of view of visual information can diminish hazard recognition and ultimately decrease operational situational awareness.” As I interpret this, the operator controlling BVLOS, stands a good chance of becoming a safety hazard; the operator’s ability to detect hazards is diminished by buildings, natural obstructions, e.g. tree lines or hills, and the distance beyond their visual acuity.

In order to operate a UAV BVLOS, the FAA can issue a waiver to the operator as per Title 14 Code of Federal Regulations (CFR) Part 107.200 – Waiver Policy and Requirements. This waiver, granted by law, can supersede the restrictions of Title 14 CFR Part 107.31 – Visual Line of Sight Aircraft Operation, where the remote pilot, visual observer and/or the controls operator “… must be able to see the unmanned aircraft throughout the entire flight …”

Part 107 is ambiguous at best, about what an operator employing a waiver uses to ‘see’ the UAV’s operating area when BVLOS. Are ‘Brand B’ UAVs only able to be tracked with ‘Brand B’ equipment? If ‘seeing’ is, e.g. a camera mounted to the UAV, can the camera ‘see’ in all directions along the X, Y and Z axes? How would it detect a bird or an ultralight aircraft? How does the UAV avoid hazards or escape becoming a hazard itself?

The Authors’ first article demonstrated the hazard a UAV may present to a General Aviation aircraft under the best visual conditions. The second article established the hurdles of tracking UAVs inserted into a smaller commercial airport’s operating area. This third article highlights the increasing challenges the FAA faces in overseeing the UAS. All three articles increase the urgency of mounting problems, long overdue for addressing. However, one thing the Authors cannot study is the most unpredictable UAS threat to aviation and public safety: Operator Maturity.

For the sake of this article, the subject of terrorist UAV manipulation is off the table; it is a valid argument, but not to the point of FAA oversight and industry coexistence. In the first paragraph of the third Article, the Authors referenced the accident between a UAV and a military helicopter. The operator, per accident report DCA17IA202AB, “was intentionally flying the drone [UAV] out of visual range and did not have the adequate knowledge of regulations and safe operating practices.” This means the operator did not have a waiver to operate BVLOS per Title 14 CFR 107.200.

Is this the first instance of UAVs being operated carelessly through the NAS? No. The FAA has documented hundreds of nightly incident reports where UAVs were operated in the approach and departure paths of commercial airliners at airports, e.g. O’Hare or JFK. These reports date back more than five years. The UAVs, playing chicken with the passenger airliners, were seen by witnesses or flight crews, but it was impossible to locate the UAVs’ operators with existing technologies.

Why would individuals perform these unsafe acts? For years local police in many states have chased individuals aiming laser pointers at helicopters and airliners; these individuals attempted to disorient or temporarily blind pilots during the most critical stage of flight – Landing. A three-year old video showed a ground operator hovering his UAV – BVLOS – directly over the main rotor of a traffic helicopter while it flew over a populated area; the video was captured by a rival station’s helicopter cameras, which then followed the UAV down to the operator, who hid behind trees so as not to be taped.

The third Article is important in understanding why Title 14 CFR Part 107 was written and why these regulations must be applied. UAS individuals are in a larger world, full of situational awareness challenges, where UAV operators are never in any personal danger and won’t suffer from their unsafe actions. This remains new territory, for the UAS industry, the aviation community and the FAA.

Next week we will look at the challenges of oversight by the FAA.

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