Sunday, February 8, 2015

ASCI 530, Assignment 4.4, UAS in the NAS



A system for maintaining safe separation of unmanned aircraft from all other types of aircraft is of critical importance if UAS are to be allowed to and successfully operate in the National Airspace (NAS).  This system must cover all types of UAS in some manner.  Currently, manned aircraft operate under visual flight rules (VFR) and instrument flight rules (IFR).  The primary purpose of these rulesets is to maintain safe separation between aircraft.  If unmanned aircraft are to successfully navigate the NAS, they must demonstrate they can adhere to these rulesets.

Regardless of the type of UAS airframe, operating an unmanned aircraft under VFR would require an aircraft that would allow the operator, at the very least, the same degree of visibility as if he/she were aloft in the aircraft.  If the aircraft were operating autonomously, without continuous input from an operator, the autonomous control system would have to demonstrate the same degree of awareness as a pilot aloft.  At the current level of technology, either of these goals would be difficult to achieve.
The most expedient method, at present, would be to require the majority of UAS to operate under IFR.  Regardless of the type of UAS airframe, operating the aircraft would require response to air traffic controller instructions, at the very least, to the same degree as a pilot aloft.  An autonomous control system would share the same requirements.  By definition, a pilot flying under IFR would be able to successfully operate the aircraft by the flight instruments, controller instructions, and without outside visual references.  This would also mean that UAS operating in the NAS would require the same equipment as a manned aircraft, such as a radio, transponder, etc.  Operators will also require IFR ratings and the accompanying materials, such as approach plates for specific airfields.  If these same standards can be met by a UAS, the current system of handling IFR traffic would suffice to handle an unmanned aircraft.

The advent of Automatic Dependent Surveillance-Broadcast (ADS-B) technology has provided a very significant improvement in determining locations, maintaining safe separation, and increasing situational awareness.  The Federal Aviation Administration (FAA) plans to spend approximately $2.1 billion on the system and has set a requirement for aircraft operating in airspace that requires a Mode C transponder to be ADS-B equipped by 2020.  If a UAS intends to operate across the range of airspace classes in the NAS, ADS-B will be required.

The possible exception to these rules would most likely be the mini (MUAV), micro (MAV), and nano (NAV) UAS categories.  These aircraft would most likely not be intended for operation in most of the more congested classes of airspace simply due to performance limitations.  For example, it would be highly unlikely for a MAV to climb to the altitude of a cruising commercial airliner.  These smaller UAS would probably be treated like recreational remote control aircraft in terms of operating rules.  However, with the expected growth of the variety and usage of UAS platforms, we can probably expect a multitude of additional rules restricting operations.  For example: Prohibitions near major sporting, arts, or music events; progressive altitude limits at certain distances from airfields; no entrance into Class B airspace; etc.

References:
FAA Pilot’s Handbook of Aeronautical Knowledge, FAA-H-8083-25A, Chapter 14: Airspace (2008).  Retrieved from https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/pilot_handbook/media/PHAK%20-%20Chapter%2014.pdf

Hampton, M. E. (2014).  ADS-B BENEFITS ARE LIMITED DUE TO A LACK OF ADVANCED CAPABILITIES AND DELAYS IN USER EQUIPAGE [Memorandum].  Washington D.C.: Dept of Transportation.

Macneil, J (n.d.).  Air Traffic Services Brief – Automatic Dependent Surveillance – Broadcast (ADS-B). In AOPA: Air Traffic Services and Technology. Retrieved from http://www.aopa.org/Advocacy/Air-Traffic-Services-,-a-,-Technology/Air-Traffic-Services-Brief-Automatic-Dependent-Surveillance-Broadcast-ADS-B

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