CASE
3
The Quest for Safety Amid Crowded Skies
Since 1926 and the passage of the Air Commerce Act, the Federal Government has had a vital commitment to aviation safety. Even before this, however, the NACA championed regulation of aeronautics, the establishment of licensing procedures for pilots and aircraft, and the definition of technical criteria to enhance the safety of air operations. NASA has worked closely with the FAA and other aviation organizations to ensure the safety of America’s air transport network.
Case-3 Cover Image: More than 87,000 flight take place each day over the United States. The work of NASA and others has helped develop ways to ensure safety in these crowded skies. Richard P. Hallion.
When the first airplane lifted off from the sands of Kitty Hawk during 1903, there was no concern of a midair collision with another airplane. The Wright brothers had the North Carolina skies all to themselves. But as more and more aircraft found their way off the ground and then began to share the increasing number of new airfields, the need to coordinate movements among pilots quickly grew. As flight technology matured to allow cross-country trips, methods to improve safe navigation between airports evolved as well. Initially, bonfires lit the airways. Then came light towers, two-way radio, omnidirectional beacons, radar, and—ultimately—Global Positioning System (GPS) navigation signals from space.[1]
Today, the skies are crowded, and the potential for catastrophic loss of life is ever present, as more than 87,000 flights take place each day over the United States. Despite repeated reports of computer crashes or bad weather slowing an overburdened national airspace system, air-related fatalities remain historically low, thanks in large part to the technical advances developed by the National Aeronautics and Space Administration (NASA), but especially to the daily efforts of some 15,000 air traffic controllers keeping a close eye on all of those airplanes.[2]
From an Australian government slide show in 1956, the basic concepts of an emerging air traffic control system are explained to the public. Airways Museum & Civil Aviation Historical Society, Melbourne, Australia (www.airwaysmuseum.com).
All of those controllers work for, or are under contract to, the Federal Aviation Administration (FAA), which is the Federal agency responsible for keeping U.S. skyways safe by setting and enforcing regulations. Before the FAA (formed in 1958), it was the Civil Aeronautics Administration (formed in 1941), and even earlier than that, it was the Department of Commerce’s Aeronautics Bureau (formed in 1926). That that administrative job today is not part of NASA’s duties is the result of decisions made by the White House, Congress, and NASA’s predecessor organization, the National Advisory Committee for Aeronautics (NACA), during 1920.[3]
At the time (specifically 1919), the International Commission for Air Navigation had been created to develop the world’s first set of rules for governing air traffic. But the United States did not sign on to the convention. Instead, U.S. officials turned to the NACA and other organizations to determine how best to organize the Government for handling all aspects of this new transportation system. The NACA in 1920 already was the focal point of aviation research in the Nation, and many thought it only natural, and best, that the Committee be the Government’s all-inclusive home for aviation matters. A similar organizational model existed in Europe but didn’t appear to some with the NACA to be an ideal solution. This sentiment was most clearly expressed by John F. Hayford, a charter member of the NACA and a Northwestern University engineer, who said during a meeting, “The NACA is adapted to function well as an advisory committee but not to function satisfactorily as an administrative body.”[4]
So, in a way, NASA’s earliest contribution to making safer skyways was to shed itself of the responsibility for overseeing improvements to and regulating the operation of the national airspace. With the FAA secure in that management role, NASA has been free to continue to play to its strengths as a research organization. It has provided technical innovation to enhance safety in the cockpits; increase efficiencies along the air routes; introduce reliable automation, navigation, and communication systems for the many air traffic control (ATC) facilities that dot the Nation; and manage complex safety reporting systems that have required creation of new data-crunching capabilities.
This case study will present a survey in a more-or-less chronological order of NASA’s efforts to assist the FAA in making safer skyways. An overview of key NASA programs, as seen through the eyes of the FAA until 1996, will be presented first. NASA’s contributions to air traffic safety after the 1997 establishment of national goals for reducing fatal air accidents will be highlighted next. The case study will continue with a survey of NASA’s current programs and facilities related to airspace safety and conclude with an introduction of the NextGen Air Transportation System, which is to be in place by 2025.
NASA, as Seen by the FAA
Nearly every NASA program related to aviation safety has required the involvement of the FAA. Anything new from NASA that affects—for example, the design of an airliner or the layout of a cockpit panel[5] or the introduction of a modified traffic control procedure that relies on new technology[6]—must eventually be certified for use by the FAA, either directly or indirectly. This process continues today, extending the legacy of dozens of programs that came before—not all of which can be detailed here. But in terms of a historical overview through the eyes of the FAA, a handful of key collaborations with NASA were considered important enough by the FAA to mention in its official chronology, and they are summarized in this section.
Partners in the Sky: 1965
The partnership between NASA and the FAA that facilitates that exchange of ideas and technology was forged soon after both agencies were formally created in 1958. With the growing acceptance of commercial jet airliners and the ever-increasing number of passengers who wanted to get to their destinations as quickly as possible, the United States began exploring the possibility of fielding a Supersonic Transport (SST). By 1964, it was suggested that duplication of effort was underway by researchers at the FAA and NASA, especially in upgrading existing jet powerplants required to propel the speedy airliner. The resulting series of meetings during the next year led to the creation in May 1965 of the NASA–FAA Coordinating Board, which was designed to “strengthen the coordination, planning, and exchange of information between the two agencies.”[7]
Project Taper: 1965
During that same month, the findings were released of what the FAA’s official historical record details as its first joint research project with NASA.[8]
A year earlier, during May and June 1964, two series of flight tests were conducted using FAA aircraft with NASA pilots to study the hazards of light to moderate air turbulence to jet aircraft from several perspectives. The effort was called Project Taper, short for Turbulent Air Pilot Environment Research.[9] In conjunction with ground-based wind tunnel runs and early use of simulator programs, FAA Convair 880 and Boeing 720 airliners were flown to define the handling qualities of aircraft as they encountered turbulence and determine the best methods for the pilot to recover from the upset. Another part of the study was to determine how turbulence upset the pilots themselves and if any changes to cockpit displays or controls would be helpful. Results of the project presented at a 1965 NASA Conference on Aircraft Operating Problems indicated that in terms of aircraft control, retrimming the stabilizer and deploying the spoilers were “valuable tools,” but if those devices were to be safely used, an accurate g-meter should be added to the cockpit to assist the pilot in applying the correct amount of control force. The pilots also observed that initially encountering turbulence often created such a jolt that it disrupted their ability to scan the instrument dials (which remained reliable despite the added vibrations) and recommended improvements in their seat cushions and restraint system.[10]
But the true value of Project Taper to making safer skyways may have been the realization that although aircraft and pilots under controlled conditions and specialized training could safely penetrate areas of turbulence—even if severe—the better course of action was to find ways to avoid the threat altogether. This required further research and improvements in turbulence detection and forecasting, along with the ability to integrate that data in a timely manner to the ATC system and cockpit instrumentation.[11]
Avoiding Bird Hazards: 1966
After millions of years of birds having the sky to themselves, it only took 9 years from the time the Wright brothers first flew in 1903 for the first human fatality brought about by a bird striking an aircraft and causing the plane to crash in 1912. Fast-forward to 1960, when an Eastern Air Lines plane went down near Boston, killing 62 people as a result of a bird strike—the largest loss of life from a single bird incident.[12]
A DeTect, Inc., MERLIN bird strike avoidance radar is seen here in use in South Africa. NASA uses the same system at Kennedy Space Center for Space Shuttle missions, and the FAA is considering its use at airports around the Nation. NASA.
With the growing number of commercial jet airplanes, faster aircraft increased the potential damage a small bird could inflict and the larger airplanes put more humans at risk during a single flight. The need to address methods for dealing with birds around airports and in the skies also rose in priority. So, on September 9, 1966, the Interagency Bird Hazard Committee was formed to gather data, share information, and develop methods for mitigating the risk of collisions between birds and airplanes. With the FAA taking the lead, the Committee included representatives from NASA; the Civil Aeronautics Board; the Department of Interior; the Department of Health, Education, and Welfare; and the U.S. Air Force, Navy, and Army.[13]
Through the years since the Committee was formed, the aviation community has approached the bird strike hazard primarily on three fronts: (1) removing or relocating the birds, (2) designing aircraft components to be less susceptible to damage from bird strikes, and (3) increasing the understanding of bird habitats and migratory patterns so as to alter air traffic routes and minimize the potential for bird strikes. Despite these efforts, the problem persists today, as evidenced by the January 2009 incident involving a US Airways jet that was forced to ditch in the Hudson River. Both of its jet engines failed because of bird strikes shortly after takeoff. Fortunately, all souls on board survived the water landing thanks to the training and skills of the entire flightcrew.[14]
NASA’s contributions in this area include research to characterize the extent of damage that birds might inflict on jet engines and other aircraft components in a bid to make those parts more robust or forgiving of a strike,[15] and the development of techniques to identify potentially harmful flocks of birds[16] and their local and seasonal flight patterns using radar so that local air traffic routes can be altered.[17]
Radar is in use to warn pilots and air traffic controllers of bird hazards at the Seattle-Tacoma International Airport. As of this writing, the FAA plans to deploy test systems at Chicago, Dallas, and New York airports, as the technology still needs to be perfected before its deployment across the country, according to an FAA spokeswoman quoted in a Wall Street Journal story published January 26, 2009.[18]
Meanwhile, a bird detecting radar system first developed for the Air Force by DeTect, Inc., of Panama City, FL, has been in use since 2006 at NASA’s Kennedy Space Center to check for potential bird strike hazards before every Space Shuttle launch. Two customized marine radars scan the sky: one oriented in the vertical, the other in the horizontal. Together with specialized software, the MERLIN system can detect flocks of birds up to 12 miles from the launch pad or runway, according to a company fact sheet.
In the meantime, airports with bird problems will continue to rely on broadcasting sudden loud noises, shooting off fireworks, flashing strobe lights, releasing predator animals where the birds are nesting, or, in the worst case, simply eliminating the birds.
Applications Technology Satellite 1 (ATS 1): 1966–1967
Aviation’s use of actual space-based technology was first demonstrated by the FAA using NASA’s Applications Technology Satellite 1 (ATS 1) to relay voice communications between the ground and an airborne FAA aircraft using very high frequency (VHF) radio during 1966 and 1967, with the aim of enabling safer air traffic control over the oceans.[19]
Launched from Cape Canaveral atop an Atlas Agena D rocket on December 7, 1966, the spin-stabilized ATS 1 was injected into geosynchronous orbit to take up a perch 22,300 miles high, directly over Ecuador. During this early period in space history, the ATS 1 spacecraft was packed with experiments to demonstrate how satellites could be used to provide the communication, navigation, and weather monitoring that we now take for granted. In fact, the ATS 1’s black and white television camera captured the first full-Earth image of the planet’s cloud-covered surface.[20]
Eight flight tests were conducted using NASA’s ATS 1 to relay voice signals between the ground and an FAA aircraft using VHF band radio, with the intent of allowing air traffic controllers to speak with pilots flying over an ocean. Measurements were recorded of signal level, signal plus noise-to-noise ratio, multipath propagation, voice intelligibility, and adjacent channel interference. In a 1970 FAA report, the author concluded that the “overall communications reliability using the ATS 1 link was considered marginal.”[21]
All together, the ATS project attempted six satellite launches between 1966 and 1974, with ATS 2 and ATS 4 unable to achieve a useful orbit. ATS 1 and ATS 3 continued the FAA radio relay testing, this time including a specially equipped Pan American Airways 747 as it flew a commercial flight over the ocean. Results were better than when the ATS 1 was tested alone, with a NASA summary of the experiments concluding
The experiments have shown that geostationary satellites can provide high quality, reliable, un-delayed communications between distant points on the earth and that they can also be used for surveillance. A combination of un-delayed communications and independent surveillance from shore provides the elements necessary for the implementation of effective traffic control for ships and aircraft over oceanic regions. Eventually the same techniques may be applied to continental air traffic control.[22]
Aviation Safety Reporting System: 1975
On December 1, 1974, a Trans World Airlines (TWA) Boeing 727, on final approach to Dulles airport in gusty winds and snow, crashed into a Virginia mountain, killing all aboard. Confusion about the approach to the airport, the navigation charts the pilots were using, and the instructions from air traffic controllers all contributed to the accident. Six weeks earlier, a United Airlines flight nearly succumbed to the same fate. Officials concluded, among other things, that a safety awareness program might have enabled the TWA flight to benefit from the United flight’s experience. In May 1975, the FAA announced the start of an Aviation Safety Reporting Program to facilitate that kind of communication. Almost immediately, it was realized the program would fail because of fear the FAA would retaliate against someone calling into question its rules or personnel. A neutral third party was needed, so the FAA turned to NASA for the job. In August 1975, the agreement was signed, and NASA officially began operating a new Aviation Safety Reporting System (ASRS).[23]
NASA’s job with the ASRS was more than just emptying a “big suggestion box” from time to time. The memorandum of agreement between the FAA and NASA proposed that the updated ASRS would have four functions:
Two other significant aspects of the ASRS included a provision that no disciplinary action would be taken against someone making a safety report and that NASA would form a committee to advise on the ASRS. The committee would be made up of key aviation organizations, including the Aircraft Owners and Pilots Association, the Air Line Pilots Association, the Aviation Consumer Action Project, the National Business Aircraft Association, the Professional Air Traffic Controllers Organization, the Air Transport Association, the Allied Pilots Association, the American Association of Airport Executives, the Aerospace Industries Association, the General Aviation Manufacturers’ Association, the Department of Defense, and the FAA.[24]
Now in existence for more than 30 years, the ASRS has racked up an impressive success record of influencing safety that has touched every aspect of flight operations, from the largest airliners to the smallest general-aviation aircraft. According to numbers provided by NASA’s Ames Research Center at Moffett Field, CA, between 1976 and 2006, the ASRS received more than 723,400 incident reports, resulting in 4,171 safety alerts being issued and the instigation of 60 major research studies. Typical of the sort of input NASA receives is a report from a Mooney 20 pilot who was taking a young aviation enthusiast on a sightseeing flight and explaining to the passenger during his landing approach what he was doing and what the instruments were telling him. This distracted his piloting just enough to complicate his approach and cause the plane to flare over the runway. He heard his stall alarm sound, then silence, then another alarm with the same tone. Suddenly, his aircraft hit the runway, and he skidded to a stop just off the pavement. It turned out that the stall warning alarm and landing gear alarm sounded alike. His suggestion was to remind the general-aviation community there were verbal alarms available to remind pilots to check their gear before landing.[25]
Although the ASRS continues today, one negative about the program is that it is passive and only works if information is voluntarily offered. But from April 2001 through December 2004, NASA fielded the National Aviation Operations Monitoring Service (NAOMS) and conducted almost 30,000 interviews to solicit specific safety-related data from pilots, air traffic controllers, mechanics, and other operational personnel. The aim was to identify systemwide trends and establish performance measures, with an emphasis on tracking the effects of new safety-related procedures, technologies, and training. NAOMS was part of NASA’s Aviation Safety Program, detailed later in this case study.[26]
With all these data in hand, more coming in every day, and none of them in a standard, computer-friendly format, NASA researchers were prompted to develop search algorithms that recognized relevant text. The first such suite of software used to support ASRS was called QUOROM, which at its core was a computer program capable of analyzing, modeling, and ranking text-based reports. NASA programmers then enhanced QUOROM to provide:
QUORUM’s usefulness in accessing the ASRS database would evolve as computers became faster and more powerful, paving the way for a new suite of software to perform what is now called “data mining.” This in turn would enable continual improvement in aviation safety and find applications in everything from real-time monitoring of aircraft systems[28] to Earth sciences.[29]
Microwave Landing System hardware at NASA’s Wallops Flight Research Facility in Virginia as a NASA 737 prepares to take off to test the high-tech navigation and landing aid. NASA.
Microwave Landing System: 1976
As soon as it was possible to join the new inventions of the airplane and the radio in a practical way, it was done. Pilots found themselves “flying the beam” to navigate from one city to another and lining up with the runway, even in poor visibility, using the Instrument Landing System (ILS). ILS could tell the pilots if they were left or right of the runway centerline and if they were higher or lower than the established glide slope during the final approach. ILS required straight-in approaches and separation between aircraft, which limited the number of landings allowed each hour at the busiest airports. To improve upon this, the FAA, NASA, and the Department of Defense (DOD) in 1971 began developing the Microwave Landing System (MLS), which promised, among other things, to increase the frequency of landings by allowing multiple approach paths to be used at the same time. Five years later, the FAA took delivery of a prototype system and had it installed at the FAA’s National Aviation Facilities Experimental Center in Atlantic City, NJ, and at NASA’s Wallops Flight Research Facility in Virginia.[30]
Between 1976 and 1994, NASA was actively involved in understanding how MLS could be integrated into the national airspace system. Configuration and operation of aircraft instrumentation,[31] pilot procedures and workload,[32] air traffic controller procedures,[33] use of MLS with helicopters,[34] effects of local terrain on the MLS signal,[35] and the determination to what extent MLS could be used to automate air traffic control[36] were among the topics NASA researchers tackled as the FAA made plans to employ MLS at airports around the Nation.
But having proven with NASA’s Applications Technology Satellite program that space-based communication and navigation were more than feasible (but skipping endorsement of the use of satellites in the FAA’s 1982 National Airspace System Plan), the FAA dropped the MLS program in 1994 to pursue the use of GPS technology, which was just beginning to work itself into the public consciousness. GPS signals, when enhanced by a ground-based system known as the Wide Area Augmentation System (WAAS), would provide more accurate position information and do it in a more efficient and potentially less costly manner than by deploying MLS around the Nation.[37]
Although never widely deployed in the United States for civilian use, MLS remains a tool of the Air Force at its airbases. NASA has employed a version of the system called the Microwave Scan Beam Landing System for use at its Space Shuttle landing sites in Florida and California. Moreover, Europe has embraced MLS in recent years, and an increasing number of airports there are being equipped with the system, with London’s Heathrow Airport among the first to roll it out.[38]
NUSAT: 1985
NUSAT, a tiny satellite designed by Weber State College in northern Utah, was deployed into Earth orbit from the cargo bay of the Space Shuttle Challenger on April 29, 1985. Its purpose was to serve as a radar target for the FAA.
The satellite employed three L-band receivers, an ultra high frequency (UHF) command receiver, a VHF telemetry transmitter, associated antennas, a microprocessor, fixed solar arrays, and a power supply to acquire, store, and forward signal strength data from radar. All of that was packed inside a basketball-sized, 26-sided