Page 27 - Forum-2020-JulyToSeptember

• Pilot-induced oscillation. developed over time to prevent them, and “The protections built into the
• Malicious interference. the deference such operations receive and present-day aviation system are far
should receive in that environment.
When one familiar with UAS looks at On the other hand, unmanned aircraft more robust than they used to be,
this list, it is immediately obvious that asserting a need or a “right” to operate although the foundation of RPAS
UAS are vulnerable to many of the same amid other aircraft, whether receiving ‘detect-and-avoid’ technologies
conditions, albeit for many different air traffic services or flying purely under rests on understanding that it
reasons. Chief among them is the RPIC’s some interpretation of “visual flight rules” is not enough for unmanned
inability to directly perceive what is (VFR), represent an entirely different
happening to the aircraft from moment to challenge. Current aviation stakeholders aircraft to ‘see’only aircraft
moment. However, even as work contin- can and should consider the rules they emitting transponder or Automatic
ues on addressing these issues in manned are required to follow; regulators must Dependent Surveillance–Broadcast
aviation, it is clear that preventive or take an objective look at how much relief (ADS-B) Out signals; they must be
corrective measures that might be effec- from rules unmanned aircraft operat- able to actively detect nonemitting
tive in that domain may be completely ing in shared airspace should enjoy and aircraft as well."
inadequate for unmanned operations. how much is warranted. In making such
One of the great virtues of unmanned determinations, the past will continue to
aircraft is that many are inherently matter. similar to that seen in the tragic 1986
more stable than manned aircraft under Finally, attentive readers undoubtedly collision of an Aeromexico airliner and a
normal conditions. Onboard automation have noticed that the second question general aviation (GA) aircraft over Cerri-
provided in many makes them extreme- posed at the start of this paper has yet to tos, California. The former was operating
ly effective at stabilizing themselves, be directly addressed: Are past accident under instrument flight rules in the Los
responding to transient conditions that scenarios in danger of being repeated due Angeles terminal control area (TCA),
might take them off their programed to the expansion of minimally regulated the predecessor to the current Class A
course, etc. However, some of their design unmanned aircraft operations in the airspace; the latter was operating legally
features—such as supercritical wings and midst of manned aircraft? under VFR but strayed into the TCA. Most
satellite antennae subject to “fuselage The author’s view is that the answer to GA aircraft at that time lacked Mode C
blanking” in some attitudes—render this is a qualified “yes.” The protections pressure reporting transponders, and the
them vulnerable to unexpected depar- built into the present-day aviation system profusion of 1200 VFR targets flying un-
tures from controlled flight. are far more robust than they used to der the TCA boundaries complicated the
Experienced UAS pilots often can be, although the foundation of RPAS air traffic controllers’ task immensely.
diagnose structural problems, inadvert- “detect-and-avoid” technologies rests on The Cerritos accident resulted in quite
ent gear extensions, and the like through understanding that it is not enough for a few changes in the U.S., including
close monitoring of the need for unusual unmanned aircraft to “see” only aircraft creation of the “Mode C veil” concept
throttle settings, higher than normal emitting transponder or Automatic De- and more-stringent communications
fuel consumption, or a constant need for pendent Surveillance–Broadcast (ADS-B) requirements for VFR aircraft flying in
heading or altitude corrections. Out signals; they must be able to actively Class B and C airspace. However, it also
detect nonemitting aircraft as well. highlighted the distraction inherent in
Current-generation transport-category having numerous transponder targets
Summing up aircraft use aircraft collision avoidance flying outside airspace for which ATC
Current conversations about the effects of systems (ACAS) and only can detect was responsible. The potential for repeat
unmanned aviation on airspace include aircraft equipped with transponders. accidents led many facilities to suppress
a significant amount of incompletely Therefore, it is possible to envision RPAS display of targets below a certain altitude
informed—and occasionally misleading— given relief from the requirement to be to avoid clutter, which in turn may indi-
blurring of existing distinctions between equipped with such avionics on the basis rectly have led to the FAA’s new guidance
“small” RPAS and larger unmanned air- of their not being designed or certified to controllers that air traffic services are
craft seeking to operate side by side with with them. The current architectures not provided to unmanned aircraft below
other aircraft, especially in controlled of both the Single European Sky ATM 400 feet AGL.
airspace. There is a not inconsiderable Research (SESAR) Joint Undertaking and Small unmanned aircraft bring with
amount of risk associated with those at the U.S. next generation air transporta- them their own unique issues, but also
the small end of the size and weight spec- tion system (NextGen) heavily rely upon can be managed to some extent by
trum interfering with terminal operations participating aircraft being comprehen- keeping them as segregated as possible
at low altitude, especially when permitted sively equipped to serve as interactive from manned aircraft. This approach
to operate in that environment more or nodes of trajectory information upon cannot work for RPAS flown among
less at will and without the possibility of which optimal clearances for all aircraft manned aircraft. In those cases, history
being “seen” either visually or electroni- may be based. Again, if equivalent equi- has taught many lessons that apply to all
cally. Addressing the hazards those oper- page requirements are not imposed upon flying, regardless of the pilot’s physical
ations present mostly will be a matter of unmanned aircraft, they will be effectively location. The aviation community would
looking at the history of midair collisions, invisible to all other aircraft in the system. be wise to reflect on them as unmanned
rules (including mandatory equipage) It is possible to envision a scenario aircraft operations continue to expand.
July-September 2020 ISASI Forum • 27