Unmanned aircraft pose myriad problems to US airspace, GAO reports

A ton of work needs to be done by military, federal and civil aviation groups if the rapidly growing unmanned aircraft community is allowed routine access to public airspace.    

In a wide-ranging report on the impact of unmanned aircraft on the country’s commercial airspace, congressional watchdogs at the Government Accountability Office today called on Congress to create an overarching body within Federal Aviation Administration to coordinate unmanned aircraft development and integration efforts.

 The GAO also called on the FAA to work with the Department of Defense, which has extensive unmanned aircraft experience to issue its program plan.  In addition, the Department of Homeland Security (DHS) assesses the security implications of routine unmanned aircraft access to commercial airspace, the GAO said. Even if all issues are addressed, and there are a number of critical problems, unmanned aircraft may not receive routine access to the national airspace system until 2020, the GAO concluded.    

But such access is certainly on the minds of the unmanned aircraft community. That’s mainly because the market for government and commercial-use unmanned aircraft could explode in the coming years.  Federal agencies such as the DHS, the Department of Commerce, and NASA alone use unmanned planes in many areas, such as border security, weather research, and forest fire monitoring. Researchers at the Teal Group said in their 2008 market study estimates that UAV spending will more than double over the next decade from current worldwide UAV spending of $3.4 billion annually to $7.3 billion, totaling close to $55 billion in the next ten years. The forecast also indicates that the US could account for 73% of the world’s research and development investment unmanned flight in the next decade.    

Still, routine unmanned aircraft access to the national airspace system poses technological, regulatory, workload, and coordination challenges, the GAO said. A key technological challenge is providing the capability for unmanned aircraft to meet the safety requirements of the national airspace system. For example, a person operating an aircraft must maintain vigilance so as to see and avoid other aircraft. However, because the airplanes have no person on board, on-board equipment, radar, or direct human observation must substitute for this capability. No technology has been identified as a suitable substitute for a person on board the aircraft in seeing and avoiding other aircraft, the GAO report stated   

Additionally, the aircraft’ communications and control links are vulnerable to unintentional or intentional radio interference that can lead to loss of control of an aircraft and an accident, and in the future, ground control stations—the unmanned airplane equivalent to a manned aircraft cockpit—may need physical security protection to guard against hostile takeover, the GAO said.    

There are other issues as well, the GAO report states, including: 

·          Many unmanned airplanes, particularly smaller models, will likely operate at altitudes below 18,000 feet, sharing airspace with other objects, such as gliders. Sensing and avoiding these other objects represents a particular challenge for unmanned aircraft, since the other objects normally do not transmit an electronic signal to identify themselves and FAA cannot mandate that all aircraft or objects possess this capability so that the aircraft can operate safely. Many small unmanned do not have equipment to detect such signals and, in some cases, are too small to carry such equipment. The Aircraft Owners and Pilots Association, in a 2006 survey of its membership, found that unmanned aircraft’s inability to see and avoid manned aircraft is a priority concern. 

·          The effort to develop the Traffic Alert and Collision and Avoidance System (TCAS), used widely in manned aircraft to help prevent collisions, demonstrates the challenge of developing a detect, sense, and avoid capability for unmanned airplanes. Although FAA, airlines, and several private-sector companies developed TCAS over a 13-year period, at a cost of more than $500 million, FAA officials point out that the designers did not intend for TCAS to act as the sole means of avoiding collisions and that the on board pilot still has the responsibility for seeing and avoiding other aircraft. FAA officials also point out that TCAS computes collision avoidance solutions based on characteristics of manned aircraft, and does not incorporate unmanned aircraft’s  slower turn and climb rates in developing conflict solutions. Consequently, FAA officials believe that developing the detect, sense, and avoid technology that unmanned aircraft would need to operate routinely in the national airspace system poses an even greater challenge than TCAS did. FAA officials believe that an acceptable detect, sense, and avoid system for airplanes could cost up to $2 billion to complete and is still many years away. 

·          The lack of protected radio frequency spectrum for unmanned operations heightens the possibility that an operator could lose command and control of the plane. Unlike manned aircraft, which use dedicated, protected radio frequencies, unmanned aircraft currently use unprotected radio spectrum and, like any other wireless technology, remain vulnerable to unintentional or intentional interference. This remains a key security vulnerability for unmanned aircraft, because in contrast to a manned aircraft where the pilot has direct, physical control of the aircraft, interruption of radio frequency, such as by jamming, can sever the plane’s only means of control. One of the experts we surveyed listed providing security and protected spectrum among the critical airplane integration technologies. 

·          Unmanned aircraft have the capability to deliver nuclear, biological, or chemical payloads, and can be launched undetected from virtually any site. In response to the events of September 11, 2001, entry doors to passenger airplane cockpits were hardened to prevent unauthorized entry. However, no similar security requirements exist to prevent unauthorized access to unmanned aircraft ground control stations—the unmanned system equivalent of the cockpit. Security is a latent issue that could impede unmanned airplane  developments even after all the other challenges have been addressed, according to one study. 

·          Although DOD has obtained benefits from its unmanned operations overseas, the agency notes in its Unmanned Systems Roadmap that unmanned aircraft reliability is a key factor in integrating unmanned systems into the national airspace system. Our analysis of information that DOD provided on 199 military unmanned airplane accidents, of varying degrees of severity, that occurred over 4½ years during operations Enduring Freedom and Iraqi Freedom, indicates that reliability continues to be a challenge. About 65% of the accidents resulted from materiel issues, such as failures of aircraft components. FAA officials noted that unmanned aircraft today are at a similar stage as personal computers in their early years before newer, more user-friendly operating systems became standard. 

·          The variety of ground control station designs across unmanned aircraft is another human factors concern. For example, pilots of the Predator B control the aircraft by using a stick and pedals, similar to the actions of pilots of manned aircraft. In contrast, pilots of the Global Hawk use a keyboard and mouse to control the aircraft. Differences in unmanned system missions could require some variation among control station designs, but the extent to which regulations should require commonalities across all ground control stations awaits further research. 

·          Because unmanned aircraft have never routinely operated in the national airspace system, the level of public acceptance is unknown. One researcher observed that as unmanned aircraft expand into the non-defense sector, there will inevitably be public debate over the need for and motives behind such proliferation. One expert we surveyed commented that some individuals may raise privacy concerns about a small aircraft that is “spying” on them, whether operated by law enforcement officials or by private organizations, and raised the question of what federal agency would have the responsibility for addressing these privacy concerns. 

While those issues are just a few outlined in the report, the GAO said a number of activities are also ongoing to address concerns.  The GAO report states some of those activities include: 

 ·          The DoD plans to spend over $7 billion in research, development, test, and evaluation funds for unmanned aircraft between fiscal years 2007 and 2013. Data from these efforts could facilitate FAA’s development of a regulatory framework to allow unmanned aircraft to have routine access to the national airspace. 

·          The FAA has budgeted $4.7 million for fiscal years 2007 through 2009 for further unmanned systems research on topics such as detect, sense, and avoid; command and control; and system safety management. NASA, FAA, and others have conducted tests to determine the capabilities of and potential improvements to detect, sense, and avoid technology. For example, in 2003, NASA installed radar on a manned aircraft that was equipped for optional control from the ground. The tests indicated that the radar detected intruding aircraft earlier than the onboard pilot, but also revealed the need for further work on the onboard sensing equipment to ensure adequate response time for the remote pilot. According to a summary of the lessons learned from these tests, the results showed some promise, but indicated that much work and technology maturation would need to occur before the tested system could be deemed ready for operational use. 

·          The FAA has established a 12,000 square mile unmanned system test center to provide airspace for testing and evaluating unmanned aircraft and to provide data for use in developing regulations. FAA expects to obtain additional data from increased coordination with the DoD. However, FAA has not yet analyzed the limited data that it has already accumulated on recent unmanned operations in the national airspace system, citing resource constraints. To address expected workload increases, FAA is introducing more automation into its work processes and has granted DoD authority to operate small unmanned systems weighing 20lbs or less, over its installations without receiving prior FAA approval. 

·          Addressing the challenge of radio frequency allocation for unmanned operations is moving forward, but may not be completed for several years. The International Telecommunication Union allocates radio frequency spectrum and deliberates such issues at periodic World Radiocommunication Conferences, the most recent of which was held in the fall of 2007. To obtain spectrum allocation for unmanned aircraft, FAA has participated with the Department of Commerce in a national preparation process to place spectrum allocation decisions on the conference’s future agenda. At the 2007 conference, delegates agreed to discuss at the next conference, in 2011, the spectrum requirements and possible regulatory actions, including spectrum allocations, needed to support the safe operation of unmanned systems. 

·          The DoD is urging manufacturers to increase reliability while keeping costs low by using such practices as standard systems engineering, ensuring that replacement parts are readily available, and using redundant, fail-safe designs. The DoD also notes in its Unmanned Systems Roadmap that, although unmanned planes suffer accidents at one to two orders of magnitude greater than the rate incurred by manned military aircraft, accident rates have declined as operational experience increased. For some airplanes, the accident rates have become similar to or lower than that of the manned F-16 fighter jet, according to the roadmap. According to a study by The MITRE Corporation, General Atomics designed the Predator B with reliability in mind, and the Altair airplane, which is a modified version of the Predator, has, among other things, triple redundant avionics to increase reliability. 

·          FAA has established an unmanned system program office and is reviewing the body of manned aviation regulations to determine the modifications needed to address unmanned aircraft, but these modifications may not be completed until 2020. As an interim step, the FAA has begun an effort to provide increased access to the national airspace system for small unmanned aircraft. The FAA is taking steps to develop data to use in developing standards, but has been slow to analyze the data that it has already collected. FAA is also coordinating with other countries to harmonize regulations.  

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