FAA air traffic controllers are responsible for guiding aircraft that are departing, landing, and moving around the terminal area at 518 U.S. airports. Airport terminal areas include “movement areas,” such as runways and taxiways, and “non-movement areas” such as ramp areas (see fig. 1). Incidents can occur in either the movement or non-movement area and include: Runway incursions: These incidents involve the incorrect presence of an aircraft, vehicle, or person on a runway. Incursions fall into three categories—pilot deviations, operational incidents, and vehicle or pedestrian deviations—depending on their cause (see fig. 2). Runway excursions: These incidents occur when an aircraft veers off the side, or overruns the end, of a runway. Wrong-surface: These incidents occur when an aircraft lands or departs, or tries to land or depart, on the wrong runway or on a taxiway (see fig. 3). Wrong surface incidents also include when an aircraft lands or tries to land at the wrong airport. Ramp area: These incidents occur when aircraft, vehicles, or people cause damage or injuries in the ramp area. FAA oversees the safety of runways and taxiways and works with partners such as airlines, airports, pilots, and others to improve safety in these areas. FAA’s oversight of ramp areas is generally exercised indirectly through its certification of airports and airlines, which have been more directly responsible for safety in these areas. Several FAA offices—with staff in D.C. headquarters, FAA regional offices, and local district offices—oversee terminal area safety, including: The Air Traffic Organization (ATO) manages air traffic control, validates reports of terminal area incidents, develops and maintains runway safety technology, and leads investigations of operational incidents. ATO also administers the mandatory reporting system, which requires air traffic controllers to report certain incidents, including runway incursions, excursions, and wrong surface landings. ATO’s Runway Safety Group leads and coordinates all FAA terminal area safety efforts. The goal of the Runway Safety Group is to improve runway and taxiway safety by reducing the risk of runway incursions, excursions, and other incidents. The Office of Airports oversees airport-related safety, including inspecting and certifying operations at commercial airports and establishing airport design and safety standards. The Office of Airports also provides grants to airports to help support safety improvements, and leads investigations of incursions caused by vehicle/pedestrian deviation. Office of Aviation Safety investigates aircraft incidents and accidents, sets aviation safety standards, and certifies aircraft and pilots. Office of Aviation Safety, Flight Standards Service (Flight Standards) inspects and certifies airlines, promotes runway safety initiatives, and provides policies and guidance for pilots. Flight Standards also administers a reporting program to obtain information on incidents involving pilots and leads investigations of incursions caused by pilot deviation. Office of Aviation Safety, Accident Investigation and Prevention oversees investigations of terminal area-safety accidents and incidents, a role which includes coordinating with the NTSB, OSHA, and other FAA offices. Runway and taxiway safety has long been a focus of FAA efforts. FAA’s fiscal year 2019-2022 strategic plan establishes four safety initiatives related to its data-driven, risk-based safety oversight approach, known as a Safety Management System (SMS), including two fiscal year 2019 safety initiatives: proactively addressing emerging safety risk by using data-informed approaches to make risk-based decisions, and reducing the risk of runway incursions and wrong surface incidents. Further, FAA’s SMS guides its terminal area oversight. For example, FAA’s order establishing the Runway Safety Program states that FAA use SMS to ensure the safety of the national airspace through evaluations, data tracking, and analysis of incidents to identify new hazards and risks, and to assess existing safety controls. In our 2011 report on FAA’s oversight of terminal area safety, we made three recommendations related to excursions, ramp areas, and information sharing, all three of which FAA has since implemented. FAA uses data from reports and investigations to analyze runway incursions. For example, a team of representatives from the Air Traffic Organization, the Office of Airports, and the Office of Flight Standards, uses information on each incursion to classify its severity into one of four categories—A through D. An example of a category A incursion occurred in June 2018 in Springfield, Missouri, when an aircraft with 53 people on board accelerated for takeoff before noticing an airport operations vehicle crossing the runway. No injuries or damage were reported, but a collision was narrowly avoided. An example of a Category C or D incursion is a pilot entering a runway without authorization, but without significant potential for a collision. FAA reports the rate of severe category A and B incursions to Congress and the public in its annual performance plan. FAA also uses data to analyze runway incursions over time. For example, FAA data show that the number and rate of reported runway incursions nearly doubled from 954 in fiscal year 2011 to 1804 in fiscal year 2018 (see fig. 4). The majority of reported runway incursions (62 percent) were pilot deviations followed by operational incidents (20 percent) and vehicle/pedestrian deviations (18 percent). According to our analysis of FAA data, the increase in reported incursions was largely due to an increase in less severe incursions. Our analysis showed that severe incursions (category A and B) in which there is a significant potential for a collision, are relatively infrequent. Category C and D incursions, in which there is less potential for a collision, are more frequent. According to FAA officials, the increase in less severe incursions may be due to increased reporting of these incidents, which we also noted in our 2011 report on terminal area safety. However, the number and rate of reported runway incursions has continued to steadily increase since then, and may also indicate an increase in the actual occurrence of incidents. In 2017, FAA developed a new metric to analyze excursions and other incidents, as well as incursions. According to FAA officials, the new metric (“Surface Safety Metric”) measures the relative riskiness of terminal area incidents by assigning a different severity weight to each incursion, excursion, or other incident depending on its proximity to a fatal accident. For example, FAA documentation states that the new metric assigns a severity weight of 1 to incidents that result in a fatal injury, 0.6 to incidents with serious injuries, and 0.3 to incidents with minor injuries. Incidents in which there are no injuries are assigned even lower severity weights—for example 0.003 for a category A incursion and 0.002 for a category B incursion. FAA officials said they will analyze these severity weights year-to-year, so they can identify trends in each type of incident and across all incidents. For example, FAA officials noted that despite an increase in the number of runway incursions from fiscal years 2011 through 2018, the estimated risk of these incidents, as measured by their severity weights, declined. FAA has developed new performance goals tied to this metric, which it plans to report to Congress and the public by the end of fiscal year 2019. FAA has analyzed excursion data through special FAA task teams and other joint industry efforts with airlines, associations, and other government agencies. Excursions occur when an aircraft veers off the side or end of a runway, and can result in serious injury, death, or property damage. For example, on September 27, 2018, a small aircraft slid off the side of the runway at Greenville Downtown Airport in South Carolina shortly after landing. The aircraft continued down a 50-foot cliff, resulting in the deaths of two people. According to data FAA provided to us, nearly 700 excursions were reported in fiscal year 2018. Additionally, several joint industry efforts and special task teams have recently analyzed excursions. For example, the Commercial Aviation Safety Team (CAST), which FAA co-leads, found that about a third of the commercial accidents in the U.S. that resulted in fatalities or irreparable damage to the aircraft from 2006 through 2015 were attributed to runway excursions. In 2013, FAA began collecting additional data on excursions, but our review of FAA’s data found the excursion data FAA has collected since then contain duplicates. In 2011, we found that FAA was not formally tracking runway excursions and recommended that FAA develop a plan to track and assess them, which FAA began doing in 2013. Prior to 2013, FAA collected excursion data from two sources—the NTSB Aviation Accident Database, which contains information gathered during NTSB investigations, and FAA’s own Aviation Safety Information Analysis and Sharing (ASIAS) database, which includes information on incidents that may not reach the level of an NTSB investigation, such as an incident without serious injuries or fatalities. In 2013, FAA began identifying excursions in a third source—mandatory occurrence reports that FAA requires air traffic controllers to file when they observe an incident. FAA officials said that the additional excursions they identified through these mandatory occurrence reports added 15 percent more annual reports to those that they had identified through only the other two sources. However, FAA officials said there are likely duplicate records in their excursion data as a single excursion could be reported in more than one of these three sources. Although we did not have enough identifying information in the excursion data FAA provided to confirm the number of duplicate reports, our analysis of excursion data did identify possible duplicates. Further, despite containing possible duplicates, FAA recently began using these excursion data in its new surface safety metric. Federal standards for internal control state that data should be appropriate, current, complete, and accurate. A 2017 FAA internal analysis also noted the importance of identifying duplicates in order to ensure accurate runway excursion data. FAA officials said that they do not know how many duplicate records there are, and that they do not have an automated way to identify (and remove) all duplicates. FAA officials said that they could manually identify and remove duplicates, but that they do not currently do this nor plan to do so because duplicate excursion records would not affect their assessment of excursion risk. FAA officials said that excursions captured solely by the mandatory occurrence reports tend to be minor, lower-risk events. However, without a process to identify duplicates, FAA is not able to verify that this statement is true, and therefore cannot accurately assess and mitigate the risk excursions pose to terminal area safety. FAA does not use data to analyze most ramp area incidents, and does not plan to do so in its new surface safety metric. While the manager of the Runway Safety Group said FAA analyzes fatal ramp accidents through its participation in CAST, it does not analyze non-fatal ramp incidents, which are estimated to occur more frequently. In addition to some airport and airline officials telling us that they likely collect ramp data, FAA’s Runway Safety Group manager said that FAA likely has data on some non-fatal ramp incidents. For example, some air traffic controllers we interviewed said that they would report any ramp area incidents they observed through FAA’s mandatory reporting process, and officials from a pilot association told us they would also report such incidents. However, FAA officials said that FAA does not plan to analyze ramp incidents in the agency’s new surface safety metric. FAA’s Runway Safety Program Manager said that FAA has not analyzed most ramp area incidents because the risk of these incidents is lower than that in other areas, such as runways, and therefore does not merit analysis. For example, the manager said that aircraft speed in the ramp area is generally slower than take-off or landing speed, and fatalities are infrequent. However, we have previously reported that ramp areas are typically small, congested areas in which departing and arriving aircraft are serviced by ramp workers, who include baggage, catering, and fueling personnel. These areas can be dangerous for ground workers and passengers. The Flight Safety Foundation, which has collected its own data on ramp safety, estimated that each year 27,000 ramp accidents and incidents occur worldwide and can be costly due to effects such as damage to aircraft and schedule disruptions. In addition, ramp areas are complex because safety responsibilities in these areas vary by airport and even by terminal. For example, officials at Boston Logan International Airport told us that the airport operator shares some responsibilities with airlines but maintains control over all ramp areas. By contrast, officials at Los Angeles International Airport told us that in terminals leased by individual airlines, the airline controls the ramp area, while the airport operator controls the ramp areas in terminals where multiple airlines operate. Officials from the Air Line Pilots Association told us that ramp areas are the “scariest part of airports.” One official gave an example of inconsistencies between airports that can cause confusion and risk, such as some airport ramp areas being marked with painted lines while others are not. Federal internal control standards state that data should be appropriate, current, complete, and accurate. In addition, FAA’s own SMS calls for FAA to use a data-driven approach to analyze safety risks so that it can control that risk. As part of those efforts, FAA began the rulemaking process in 2010 to require airports to implement SMS, through which airports would analyze risks in runways, taxiways, and ramp areas, but as of August 2019 this rule had not been finalized. Although some airport officials we interviewed said they are voluntarily implementing SMS and could be collecting data on ramp area incidents, FAA—with its role in overseeing safety at all commercial airports—is better positioned to take steps to analyze ramp incidents across all U.S. airports. For example, an individual airport implementing SMS would analyze ramp area incidents at that airport, but FAA could analyze ramp area incidents and identify trends across hundreds of airports as it does for other terminal area incidents described above. Beginning to analyze ramp area incidents, for example in its new metric, would provide FAA with information necessary to mitigate ramp area incidents and ensure that it is directing its efforts to the riskiest parts of the terminal area. FAA, airports, and airlines have implemented multiple efforts, including technologies, to improve runway, taxiway, and ramp safety; FAA’s efforts, which are coordinated by the Runway Safety Group, focus primarily on runway and taxiway safety. FAA’s primary runway and taxiway safety effort is the Runway Safety Program, whereby staff develop national and regional runway safety plans, analyze data on runway and taxiway incidents, and help local air traffic control managers organize annual Runway Safety Action Team (RSAT) meetings at which FAA, airport operator, and other stakeholders at each airport discuss recent runway and taxiway incidents. Prior to each RSAT, FAA’s Regional Runway Safety Program Managers we met with told us they compile and share available information on each incident that occurred in the last year at the airport with the local air traffic manager. This information may include trends in incursions, the location of each incident on an airport map, and results from vehicle/pedestrian deviation investigations conducted by the FAA Office of Airports. Each air traffic manager then presents this information to attendees, who may include staff from FAA’s Office of Airports or Flights Standards, the airport operator, and local pilots. Participants discuss the prior year’s incidents, identify risks, and develop a plan to mitigate these risks. For example, attendees at an RSAT in Phoenix, Arizona, discussed risk factors that could be contributing to pilot deviations, and identified that pilots could be missing taxiway markings that instruct pilots to stop before proceeding onto a runway. Consequently, these RSAT attendees developed a plan to add lights to the surrounding area to improve visibility. The attendees also tasked air traffic managers with developing a program to provide annual tours of the tower and airfield to local pilots and personnel working on the airfield to show both parties what the other sees during flight operations. Another important FAA effort is the Runway Incursion Mitigation (RIM) Program established by the Office of Airports in 2015 to identify strategies to mitigate areas of airport runways or taxiways that do not meet current FAA airport design standards and have high incursions rates (“RIM locations”). There can be multiple RIM locations at a single airport. FAA considers locations for inclusion in the RIM inventory based on whether the location has a non-standard design and has experienced three or more incursions in a given calendar year, or averaged at least one incursion per year over the course of the RIM program. At RIM locations, FAA provides funding and technical assistance to airports to mitigate the risk of incursions, such as by changing airport design and by improving runway and taxiway signage. For example, the airport may reconfigure a taxiway to intersect a runway at a 90-degree angle (the FAA standard), or install “hold position” signs at intersections between two runways. According to FAA, at the end of fiscal year 2018, FAA had helped airports mitigate 33 RIM locations through the program, leaving 135 locations across 79 airports that still needed to be mitigated. FAA also collaborates with industry stakeholders to identify and address runway and taxiway safety issues. For example, FAA serves as Co-Chair of CAST, which analyzes data across airports to identify root causes of incidents and develop and track mitigations to address those causes. For instance, through CAST, FAA and industry stakeholders developed training for air traffic controllers to mitigate the risk of runway excursions. The training described factors that can contribute to runway excursions such as adverse winds, wet or contaminated runways, or unstable aircraft approaches. In addition, in 2015, FAA convened a forum of aviation stakeholders representing government, industry, and labor called the Runway Safety Call to Action which developed 22 short-, medium-, and long-range mitigations to address the rising number of reported runway incursions. In 2018, the DOT Office of Inspector General reviewed FAA’s progress in implementing these 22 mitigations and made three recommendations to address implementation challenges it identified, including consolidating duplicate mitigations and, as mentioned below, developing a plan to measure their effectiveness. As of August 2019, FAA had not implemented these recommendations. Individual airport operators and airlines have implemented their own efforts to improve runway, taxiway, and ramp safety. For example, officials who manage Daniel K. Inouye International Airport in Honolulu, Hawaii, told us that they changed the location of markings in an airport area known to be confusing to some pilots, which reduced incursions at this location. In addition, officials from Airlines for America and the Regional Airlines Association told us airlines host safety meetings where they leverage their collective data to identify and address industry-wide safety trends. Officials told us that one of the working groups at these airline safety meetings specifically discusses issues and solutions pertaining to the ramp area. FAA, airports, and airlines fund multiple technologies to improve runway and taxiway safety, primarily through increasing air traffic controller, pilot, and vehicle operator awareness of their surroundings. See Table 1 for technologies in place or in development. FAA surveillance technologies are multi-million dollar programs designed to help air traffic controllers identify aircraft and vehicles in the terminal area. For example, at the 35 airports where ASDE-X has been installed since 2011, FAA estimated the total program cost to FAA to be more than $800 million. In-aircraft technologies like those mentioned above help pilots identify their location on runways and taxiways, and could mitigate risks of injuries and damage caused by excursions. FAA has taken steps to improve terminal area safety, but has not assessed the effectiveness of many of its runway and taxiway safety efforts. For example, FAA has not evaluated how its primary efforts such as ASDE-X, ASSC, or the Runway Safety Program contribute to runway and taxiway safety, despite having implemented these efforts years ago. In some instances, FAA has taken steps to evaluate its terminal-area safety efforts. For example, FAA tracks the Runway Incursion Mitigation Program’s outcomes and the number of runway excursions safely stopped by an Engineered Material Arresting System (EMAS). FAA also contracted with a research organization in 2017 to evaluate the effectiveness of Runway Status Lights on the runway incursion rate at 15 airports. Further, the Runway Safety Program manager described other instances in which local airport officials have taken steps to evaluate the effect of mitigations at those airports. For example, one of FAA’s runway safety offices assessed the effect of five informational videos it produced, to highlight issues identified at specific airports, on runway incursions at those locations after the videos were released. However, FAA has not assessed the effectiveness of many of its numerous other runway and taxiway efforts described above and FAA officials told us that FAA does not have a plan to do so. Officials told us that they believe that the assessments described above are sufficient, based on the availability of agency resources. In June 2018, the DOT IG reported a similar finding related to its assessment of FAA’s 2015 Runway Safety Call to Action, described above. The DOT IG reported that FAA had a plan to track the completion of mitigations aimed at improving runway and taxiway safety, but not to link the mitigations to quantifiable goals or metrics that would measure their effectiveness in reducing runway incursions. FAA’s guidance on the Runway Safety Program states that FAA may evaluate the effectiveness of its runway safety programs, and the extent to which they are helping FAA meet its safety goals. In addition, in the 2016 Evaluation Roadmap for a More Effective Government, the American Evaluation Association stated that agencies should consistently use program evaluation and systematic analysis to improve program design, implementation, and effectiveness and to assess what works, what does not work, and why. Evaluating a program’s effectiveness can include methods such as surveying a program’s managers (e.g., regional runway safety program managers), or comparing a program’s performance to an evaluative criterion (e.g., a measure of terminal area safety). Without assessing the effectiveness of its range of efforts, FAA cannot determine the extent to which each of its efforts contribute to its goal of improving runway and taxiway safety, or whether other actions are needed. As discussed previously, FAA has efforts designed to increase runway and taxiway safety that range from periodic stakeholder meetings to multi-million dollar ground surveillance systems. By assessing the effectiveness of its primary efforts, FAA may be better positioned to make decisions about how to target its limited resources within and among these efforts. We also found that FAA may be missing opportunities to improve its terminal-area safety efforts, including improving communication within FAA. Specifically, FAA Regional Runway Safety Program staff told us that they do not receive the results of most runway incursion investigations— information that could aid RSAT discussions about preventing these incidents in the future. Four of FAA’s five Regional Runway Safety Program Managers we interviewed reported that, they did not receive the results of investigations of pilot deviations—which constitute the majority of runway incursions—from the Office of Flight Standards. As part of its investigations of these incursions, Flight Standards identifies possible causes and implements mitigations, such as additional pilot training. However, FAA does not require Flight Standards to automatically provide their investigations of runway and taxiway incidents to the Runway Safety Group, which could enhance runway and taxiway safety. FAA officials said that FAA requires Flight Standards to make its investigations available to Runway Safety Group staff, if requested, but acknowledged that this does not always result in Runway Safety Group staff receiving these investigations in a timely manner. FAA officials said they are in the process of implementing additional processes to improve communication between Flight Standards and the Runway Safety Group, but documentation on these processes FAA provided to us did not address getting investigations to Runway Safety program staff in a timely manner. Without this information, the Regional Runway Safety Program Managers may be unable to provide air traffic managers with relevant information on most incursion investigations as they prepare to host their annual RSAT meetings. The manager of the Runway Safety Group told us that Regional Runway Safety Program Managers may request individual investigations from regional Flight Standards officials, but that it would be time consuming for these regional managers to make such requests for every pilot deviation. One of FAA’s objectives is to improve runway and taxiway safety, and federal internal control standards state that management should internally communicate the information necessary to help meet its objectives. Without timely access to the results of Flight Standards’ incident investigations, Regional Runway Safety Program Managers—and therefore, local air traffic control managers—may not have all of the relevant information they need to develop appropriate runway and taxiway safety mitigation strategies and plans. Selected airport operators we interviewed also reported that they may not have all information they need to develop appropriate terminal area safety mitigation strategies. Specifically, most of those we interviewed reported that air traffic control managers did not provide them with complete and timely information on all runway and taxiway incidents. Six of 10 airport operators we interviewed told us that air traffic control managers did not notify them of all runway and taxiway incidents as they happened. Further, some airport operators told us that they were not aware of all incidents until the annual RSAT meeting. For example, the operator of one airport told us that the air traffic manager notifies the airport of vehicle/pedestrian deviations immediately, but not of operational incidents or pilot deviations. The Manager of the Runway Safety Program also confirmed that communication varies by airport operator and air traffic manager. According to federal internal control standards, management should communicate quality information externally so that external parties can help the entity achieve its objectives and address related risks. Further, according to air traffic control procedures, controllers are required to report as soon as possible to airport managers and others “any information which may have an adverse effect on air safety.” However, this requirement does not specify the types of terminal area safety incidents to which this applies. Also, through a 2018 internal risk management process, FAA identified the need for enhanced communication among airport management, the FAA Air Traffic Organization, and pilots at towered airport facilities, in order to mitigate the safety risks associated with runway incursions. Lacking complete information on runway and taxiway incidents at their airports could hamper airport operators’ ability to develop appropriate safety strategies or make investment decisions related to safety in a timely manner. For example, the operator of one airport told us that not being notified of operational incidents means the airport does not have a complete picture of the safety incidents there, which limits their ability to identify trends or training needs. FAA’s safety oversight approach is designed to use data to identify hazards, manage risks, and mitigate them before an accident occurs. FAA uses data to analyze runway incursions, and recently developed a new metric to track the risk of terminal-area incidents. However, without leveraging data to analyze all terminal-area incidents, FAA may be missing opportunities to better target the agency’s resources, and ultimately to further improve safety. For example, because FAA does not have a process to eliminate all duplicates from its excursion data, it does not have assurance that its excursion data are accurate, and it may be missing opportunities to mitigate the risks excursions pose. Similarly, taking steps to analyze ramp area incidents by identifying such incidents in its new metric would help FAA determine whether it needs to focus more on improving safety in ramp areas. In addition, establishing a plan to evaluate all of its runway and taxiway safety efforts would help FAA direct its resources toward activities and technologies proven to enhance safety and identify ways to strengthen those efforts. Moreover, improving internal communication among FAA offices could make the annual Runway Safety Action Team meetings—a key component of FAA’s terminal area safety efforts—more effective. And last, improving external communication between air traffic managers and airport operators would help airports identify and implement needed mitigations more quickly. We are making the following five recommendations to FAA: 1. The Runway Safety Manager should develop a process to identify and remove duplicate excursion records. (Recommendation 1) 2. The Runway Safety Manager should take steps to analyze data on ramp area incidents in FAA’s new surface safety metric. (Recommendation 2) 3. The Runway Safety Manager should establish a plan to assess the effectiveness of all of FAA’s terminal area-safety efforts, including Airport Surface Detection Equipment, Model X (ASDE-X) and the Runway Safety Program. (Recommendation 3) 4. The Administrator of FAA should require Flight Standards to share the results of its investigations with the Runway Safety Group, in a timely manner. (Recommendation 4) 5. The Administrator of FAA should require air traffic control managers to share information on terminal area incidents, such as operational incidents and pilot deviations, with airport operators, in a timely manner. (Recommendation 5) We provided the Department of Transportation (DOT), the Department of Labor (DOL), the National Aeronautics and Space Administration (NASA), and the National Transportation Safety Board (NTSB), with a draft of this report for review and comment. In its written comments reproduced in appendix I, DOT concurred with our recommendations. DOL, NASA, and NTSB did not provide technical comments. As agreed with your offices, unless you publicly announce the contents of this report earlier, we plan no further distribution until 11 days from the report date. At that time, we will send copies to the appropriate congressional committees, DOT, DOL, NASA, NTSB, and other interested parties. In addition, the report will be available at no charge on the GAO website at http://www.gao.gov. If you or your staff have any questions about this report, please contact me at (202) 512-2834 or krauseh@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report. GAO staff who made major contributions to this report are listed in appendix II. In addition to the individual named above, other key contributors to this report were Heather MacLeod (Assistant Director); Sarah Farkas (Analyst-in-Charge); Dave Hooper; Josh Ormond; Madhav Panwar; Steven Rabinowitz; Laurel Voloder; Madeline Welter; and Elizabeth Wood.
U.S airspace system is one of the safest in the world, but incidents and near misses at and around U.S. terminal areas still occur. FAA oversees the safety of runways and taxiways and works with industry partners—including airlines, airports, pilots, and others—to improve safety in these areas. Despite FAA's continued efforts, the number of reported terminal area incidents has increased over time. GAO was asked to review various issues related to runway safety and to update its prior work on airport terminal areas. This report examines: (1) the extent to which FAA uses data to analyze terminal area incidents and (2) efforts FAA and others have implemented to improve terminal area safety, and how FAA assesses their effectiveness. GAO analyzed FAA data; interviewed officials from 10 airports selected based on high runway incident rates in the past 3 years, among other factors; and interviewed federal and industry officials. The Federal Aviation Administration (FAA) uses data to analyze some types of incidents in airport “terminal areas”—runways, taxiways, and ramps. For example, FAA uses data to analyze runway “incursions”—the incorrect presence of an aircraft, vehicle, or person on the runway. According to FAA data, the rate of reported runway incursions nearly doubled from fiscal years 2011 through 2018, with most of this increase due to a rise in reports of less severe incursions, or those without immediate safety consequences. However, GAO found that FAA has not identified or removed all duplicates from its data on runway “excursions”—when an aircraft veers off or overruns a runway—which limits FAA's ability to accurately analyze these incidents. Additionally, FAA does not use data to analyze incidents that occur in ramp areas—the parts of terminal areas where aircraft are prepared for departure and arrival—where injuries to workers and damage to aircraft can occur. Without a process to leverage accurate excursion and ramp incident data, FAA may not be able to assess the risk these incidents pose to passengers, airport staff, and others. FAA, airports, and airlines have implemented multiple efforts to improve terminal area safety, but FAA has not assessed the effectiveness of many of its efforts. For example, FAA has funded multiple technologies to improve runway safety, such as Airport Surface Detection Equipment, Model X (ASDE-X)—a ground surveillance system that enables air traffic controllers to track landing and departing aircraft and alerts controllers of potential collisions. However, FAA has not assessed the effectiveness of ASDE-X. Similarly, FAA has not assessed the effectiveness of its Runway Safety Program, whereby FAA staff, along with local airport stakeholders, provide data and support to local air traffic managers to help identify and manage terminal area safety incidents. FAA has taken steps to evaluate some of its terminal-area safety efforts, such as tracking the number of runway excursions safely stopped by a lightweight, crushable concrete designed to stop or greatly slow an aircraft that overruns the runway. However, without assessing how all of FAA's efforts contribute to its goal of improving runway and taxiway safety, FAA cannot determine the extent to which it is targeting its limited resources to the most effective strategies. GAO is making five recommendations including that FAA identify and remove duplicate excursion data, develop processes to analyze ramp area incidents, and establish a plan to assess the effectiveness of its terminal area safety efforts. FAA concurred with the recommendations.