General aviation is characterized by a diverse fleet of aircraft flown for a variety of purposes. In 2010, FAA estimated that there were more than 220,000 aircraft in the active general aviation fleet, comprising more than 90 percent of the U.S. civil aircraft fleet. Included among these aircraft are airplanes, balloons, unmanned aircraft systems, gliders, and helicopters. (See fig. 1.) Airplanes comprise the vast majority—almost 80 percent—of the general aviation fleet. According to a 2009 FAA study, general aviation airplanes have an average age of 40 years. In addition, most are single-engine piston, such as the Beechcraft Bonanza, Cessna 172, and Piper Archer. FAA designates a small, but growing, portion of the general aviation fleet as “experimental.” These include aircraft used for racing and research as well as exhibition aircraft, such as former military aircraft known as warbirds. The largest group of experimental aircraft—and the fastest growing segment of the general aviation fleet, according to FAA—is defined by FAA as “experimental-amateur built” (E-AB). Individuals build E-AB aircraft either from kits sold by manufacturers or from their own designs. E-AB aircraft can contain previously untested systems, including engines not designed for aircraft use, and modifications of airframes, controls, and instrumentation. The E-AB fleet is diverse, ranging from open-framework designs with no cabin structure to small, pressurized airplanes able to fly long distances. The majority are simple craft used primarily for short personal flights. The expertise of the builders varies, as does the experience of the pilots and the availability of training for transitioning to the aircraft. Following a successful inspection of the aircraft and documentation review, FAA issues a special airworthiness certificate in the experimental category to the aircraft’s builder and assigns operating limitations in two phases specifying how and where the aircraft can be flown.the builder determines the aircraft’s airspeed and altitude capabilities and develops a flight manual. Phase II refers to normal operations after the flight testing is completed. Phase I is the required flight test period, in which General aviation aircraft can be used for a wide variety of operations, although about 78 percent of general aviation operations fall under one of four types: personal (e.g., a pilot taking his family on a sightseeing trip); business (e.g., a pilot flying herself to a meeting); corporate (e.g., a professionally-piloted aircraft transporting corporate employees around the globe); and instructional (e.g., a student flying with a certified flight instructor). These operations are conducted from the more than 2,950 public use general aviation airports (which primarily serve general aviation aircraft) as well as from thousands of other airports (including those that support commercial air service) and landing facilities (e.g., heliports). General aviation flights operate under various federal aviation regulations. For purposes of this report, our definition of general aviation includes flights operated under part 91 general operation and flight rules. GAO-12-117. Our definition of flight-instructor based schools includes individual flight instructors. more information about the estimated number of active airplane pilots and selected pilot certificate requirements and limitations. Various offices within FAA are responsible for ensuring general aviation safety, most notably the Flight Standards Service, Aircraft Certification Service, Office of Accident Investigation and Prevention, and Office of Runway Safety. According to FAA, the agency’s fiscal year 2011 budget submission included nearly $203 million for activities within the Aviation Safety organization related to the top priority of reducing the general aviation fatal accident rate. FAA’s responsibilities include administering aircraft and pilot certification, conducting safety oversight of pilot training and general aviation operations, and taking enforcement actions against pilots and others who violate federal aviation regulations and safety standards. FAA also collects general aviation fleet and flight activity data through an annual survey and supports the NTSB by gathering information about general aviation accidents. According to NTSB officials, FAA collects information on the vast majority of general aviation accidents. NTSB is responsible for all aviation accident investigations—using the information gathered by FAA and its own investigators—and for determining the probable cause of accidents. NTSB uses a coding system of aircraft accident categories and associated phases of flight that are useful in describing the characteristics and circumstances of aviation accidents. For ease of interpretation and to categorize similar events, NTSB identifies one event as the “defining event” of the accident, which generally describes the type of accident that occurred—hard landing, midair collision, or fuel exhaustion, for example. In addition, NTSB identifies the causes of an accident and the contributing factors, which describe situations or circumstances central to the accident cause. Just as accidents often include a series of events, the reason those events led to an accident may reflect a combination of multiple causes and contributing factors. For this reason, a single accident report can include multiple cause and contributing factor codes. NTSB also collects descriptive information about the environmental conditions, aircraft, and people involved in aviation accidents. It captures its findings and descriptive information in its Aviation Accident Database. NTSB calculates general aviation accident and fatality rates, which it does using its own accident data and FAA’s annual estimates of general aviation flight activity. NTSB may also recommend regulatory and other changes to FAA and the aviation industry based on the results of its investigations and any studies it conducts. The U.S. general aviation industry includes a number of trade groups, “type clubs,” and other organizations that actively promote the importance of safety and, in many cases, offer educational opportunities to pilots. Many of the groups also work with FAA on advisory and rulemaking committees. Prominent trade organizations include the Aircraft Owners and Pilots Association (AOPA), the Experimental Aircraft Association (EAA), the General Aviation Manufacturers Association (GAMA), and the National Business Aviation Association (NBAA). The Society of Aviation and Flight Educators (SAFE) and the National Association of Flight Instructors represent certified flight instructors and other aviation educators. The American Bonanza Society (ABS), the Cirrus Owners and Pilots Association, and the Lancair Owners and Builders Organization are examples of the several general aviation type clubs. Our analysis of NTSB accident data showed that the annual number of general aviation accidents generally decreased for 1999 through 2011. We also identified several characteristics of accidents with respect to the types of operations and the causes of the accidents. These characteristics were largely consistent with observations made during our last review of general aviation safety in 2001. To better understand these characteristics, where possible, we sought to measure their occurrence in numbers of accidents in relation to their overall occurrence in, for instance, total flight hours or pilot certifications as estimated by FAA. In doing so, we identified some accident characteristics that, based on our analysis, appear to occur disproportionately. However, we also identified methodological and conceptual limitations with the activity data—particularly the General Aviation and Part 135 Activity Survey that FAA uses to estimate annual flight hours and the number of active aircraft—that we discuss later in this section. See table 2 for a summary of the characteristics of general aviation accidents according to our analysis of the NTSB accident data. From 1999 through 2011, nonfatal accidents involving general aviation airplanes generally decreased, falling 29 percent, from 1,265 in 1999 to 902 in 2011. Fatal accidents generally decreased as well, falling 24 percent. Figure 2 indicates the number of fatal and nonfatal accidents for each year we reviewed. During this period of time, though the majority (approximately 56 percent) of all accidents resulted in no injuries, there were more than 200 fatal accidents each year. From 1999 through 2011, personal operations accounted for 73 percent of airplanes in nonfatal general aviation accidents and 77 percent of airplanes in fatal general aviation accidents. (See fig. 3.) This is not a new phenomenon. As we reported about accidents occurring in 1998, personal operations accounted for more than 75 percent of fatal general aviation accidents. From 1999 through 2011, airplanes flying instructional operations were the second most often involved in accidents. However, instructional operations were also the operation with the smallest proportion of fatal accidents. According to our analysis, almost 38 percent of accidents that occurred during instructional flying involved hard landings or loss of control while the aircraft was on the ground. These types of events are less likely to cause fatalities than other types of events. It is also possible that the presence of a certified flight instructor onboard to share the management of the cockpit and other tasks may have contributed to the lower fatality rate for instructional operations. Corporate operations, in which a professional pilot flies an aircraft owned by a business or corporation, was the least common type of operation to be involved in general aviation accidents. Corporate operations accounted for less than 1 percent of fatal general aviation accidents and less than 0.5 percent of nonfatal accidents. From 2008 through 2011, there were no fatal accidents involving corporate airplanes, giving corporate operations an accident record similar to that of commercial air carriers. Again, this is not a new phenomenon. As we reported in 2001, the low number of accidents involving corporate operations is attributable to a number of factors, including the pilot’s training, experience, and participation in ongoing training to maintain and improve their skills, as well as the safety equipment that is typically installed on corporate aircraft. According to a representative of the NBAA, an organization representing companies that rely on general aviation aircraft to conduct business, most corporate operations also benefit from advanced technologies, including avionics that provide synthetic vision and terrain displays; auto-throttle, which helps maintain airspeed; and fuel gauges that are built to the standards required for commercial airliners. Further, airplanes used for corporate purposes are often powered by turbine engines and may be subject to additional safety requirements. Flying for corporate purposes can also differ from other types of flying.