The FAA has been tasked with safely integrating unmanned aircraft into the national airspace system. To fulfill this mandate, the FAA adopted a “phased, incremental, and risk-based approach to rulemaking.” In order for this approach to work, however, the nature of the risk must be known in an exact and quantifiable way. While this approach provides the most flexibility, it also results in a long and drawn out rulemaking process.
A good example of this is the new rulemaking for night operations. Commercial UAS operations have been legal for nearly five years. For the first two years, all flights were limited to daylight hours. After that, the FAA granted very limited Exemptions to a select group of operators for night flight. When Part 107 was released, it still prohibited routine night flights, but afforded a more streamlined waiver process for obtaining permission. It is only now, with hundreds of night flight waivers granted, that the FAA has proposed a uniform night operations rule.
As the industry moves into fully autonomous flight beyond visual line of sight, the hard questions regarding the risks UAS pose to other aircraft have to be fully addressed. The answers become even more urgent when we consider that UAS technically capable of autonomous flight beyond visual line of sight are widely available to an untrained public at a reasonable price.
Unfortunately, people unbuoyed by supporting facts dominate the public debate on these questions, claiming, “It is just a piece of plastic, how much damage can it do?” This is why the work of organizations such as Assure is so important to keep the rulemaking process advancing.
Assure has run studies to attempt to quantify comprehensively the actual damage potential from a small quadcopter or fixed wing UAS. According to its studies, a substantial risk to the engine fan blades of a commercial jet exists if it ingests a small UAS. This damage includes failure of multiple blades, depending on the aircraft’s orientation and whether the UAS struck the center of the engine or the outer edges of the blades. The study also concluded that damage to the engine was more severe than what would result from an equivalent bird strike.
The study also showed that other parts of the aircraft were far more vulnerable to catastrophic damage from a small UAS than the engine. For example, the study demonstrated significant vulnerabilities in parts of the leading edge of the wing and tail, particularly the vertical and horizontal stabilizers. Damage included the failure of the primary structure of the control. In addition, the study noted that penetration of the aircraft by a ruptured battery posed a fire risk, and that overall, a UAS collision caused greater structural damage than a bird strike at an equivalent energy level.
The aviation industry achieved its current, stunning safety record when “gut feelings” and “conventional wisdom” were rejected in favor of a data-driven method of doing business. Only by constantly auditing and monitoring performance and quantifying risk can the right conclusions be reached. While this might result in a rulemaking process that is slower than we might like, we have to ask whether the potentially catastrophic alternative is acceptable.