Introduction
The Next Generation Air Transportation System (NextGen) that is
currently being developed by the Federal Aviation Administration (FAA) and it
aviation industry partners is looking to modernize the current National
Airspace System. NextGen will be a
Global Positioning System (GPS) based system rather than the radar based system
that we currently use. While Next Gen is
composed of many other components than GPS this feature is what will assist in
the integration of UAS into the National Airspace (NAS).
A major factor in the safe operation of UAS in the NAS is the
sense-and-avoid capability (SAA) that many systems are lacking at this
time. While several SAA systems are
currently under development none of them have been operationally deployed. UAS will need to meet or exceed the same
level of SAA that manned aircraft do.
Figure 1 shows a comparison of SAA between manned and unmanned aircraft.
NextGen
Next Gen is a new Air Traffic Control (ATC) system that with the
use of GPS will allow more efficient flights and greater safety while allowing
more planes into our already congested airspace. By making more efficient departures, flight
routes, and arrivals Next Gen will save billions of dollars in fuel costs which
in turn saves fuel and is better for the environment because fewer emissions
are released into the atmosphere. Next
Gen will not only save money and fuel but it will make flying more enjoyable
for passengers and allow freight to be flown more efficiently and quickly due
to more flights and better routes.
There are many hardware and software components that make up the
NextGen system along with new regulations, procedures, and guidelines to be
used by aviation industry. UAS will need
to fit into the NextGen system the same as any other aircraft. There will be many challenges in doing so
including aircraft design and aircrew training but they are not insurmountable
problems.
UAS in NextGen
There are many hurdles to allowing UAS unrestricted access to the
NAS. This encompasses everything from
UAS manufacturing, flight operations, crew training, aircraft capabilities, and
maintenance. Like manned aircraft UAS
will need to meet FAA standards in all of these categories to be allowed to fly
in the NAS. “To gain full access to the
NAS, UAS need to be able to bridge the gap from existing systems requiring accommodations
to future systems that are able to obtain a standard airworthiness
certificate.” (Integration, 2013, p. 6)
The Airline Pilots Association backs this sentiment up and their
position is that no UAS should be allowed into the NAS until they meet all the
same standards that manned aircraft do.
“This means the aircraft must be designed
to have the same types of safety features, reliable, redundant systems and
maneuverability as the other airspace users. UAS operators must meet all the
certification and fitness requirements of air carriers, and the ‘pilots’ flying
the UAS aircraft must meet equivalent training, qualification, and licensing
requirements as pilots of aircraft in the same airspace.” (Air Line Pilots Association,
International [ALPA], 2011, p. 1)
While most of the requirements that the ALPA feel are necessary
for UAS to fly in the NAS are sound many of them show a lack of understanding
and possibly a bias to keep UAS out of the NAS.
For example, there is no valid reason that a UAS pilot needs to have the
fitness requirements of manned pilot. UAS pilots remain on the ground and do
not encounter the same physical stresses that manned pilots do. While an aviation medical should be required
separate guidelines will need to be established for UAS. Currently U.S. Army UAS operators are
required to have a military Class IV physical which is the same level as ATC
personnel.
UAS
Type
The size and use of UAS will greatly influence their ability to
fly in the NAS and the limitations that will be placed on them. While all UAS will be required to meet
minimum standards their size and role will determine where and how they can fly
in the NAS. For instance, a backpack
capable UAS that is being used for search and rescue applications will be very
restricted on the type and amount of equipment it can carry because of size and
payload capacity. Because this type of
UAS will be unable to carry the necessary equipment to fly unrestricted in the
NAS and because its mission will not require this it will most likely be
restricted to radio control (R/C) aircraft type restrictions. This would limit the aircraft to flying at
less than 400’ AGL and within visual range of the operator at all times. A larger aircraft such as a Predator class
UAS will be required to meet all NextGen requirements such as full sense-and-avoid
capability and ADS-B along with all the other required equipment and
capabilities for NextGen operations.
Because this type of UAS has the ability to carry this equipment and its
mission will most likely require it they will have to meet these standards.
Human
Factors
The biggest human factor that will be involved with the
integration of UAS into the NAS with NextGen will be the proper design and
implementation of the UAS Ground Control Station (GCS). The GCS is already the weakest link
concerning the safe flight of UAS mainly because most current generation GCSs
were rushed into service for military use and did not take human factors into
account. The fact that there is no
established standard for UAS GCS design across manufacturers is a major factor
in this. While current GCSs already do a
poor job of providing critical information to the operator/pilot in an
intuitive and easy to use format the problem will only get worse with the
increased level of information equipment required by NextGen. UAS have a leg up on many manned systems
because they are already highly GPS based and this will be in the UAS favor
during the transition but proper human factors considerations will be a key
point that needs to be addressed. If
future GCS design does not have a human factors standard to conform to and UAS
continue to have a higher than normal accident rate because of this it will
severely limit the ability of UAS to fly in the NAS.
Lost
Link
Because UAS are susceptible to lost link there will need to be
procedures and requirements in place to standardize what a UAS does in the case
of lost link. This will again be
affected by the size, type, and mission of the UAS. Small within visual range UAS may have a
requirement to return to the launch point and land immediately upon lost link
while larger UAS flying Beyond Line of Sight (BLOS) will need to fly to
appropriate loiter areas and broadcast lost link on ADS-B and other systems.
Current systems for UAS lost link do not give ATC a high enough
confidence level that they can adequately predict and reroute traffic for safe
operations. In some cases where a
working relationship has been established and ATC is fully aware of UAS lost
link procedures operations can be safely conducted. However, with full NAS integration this will
not always be a viable solution. Figure 2
shows a flow chart representing lost link reporting and ATC reaction
capability.
As NextGen and UAS mature larger aircraft may be able to use
NextGen and SAA equipment to land autonomously at their home airport without
disruption of other air traffic and greatly reducing or eliminating the
predictability problem altogether.
Summary
While there are many challenges ahead for UAS to be integrated
into the NAS along with NextGen it is critical that they do so. The benefits and unique capabilities that UAS
bring are vital to national defense as well as the national economy. UAS have many capabilities that will make
this transition easier such as accurate autopilots and GPS based navigation but
because of their vast difference in size and capabilities UAS will require
specific regulations that will differ from manned aircraft. SAA capability and Lost Link procedures will
be some of the biggest issues that will need to be resolved for this to
happen. While this will take time and a
lot of work these issues are not insurmountable.
References
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