Aviation safety

Aviation safety is the study and practice of managing risks in aviation. This includes preventing aviation accidents and incidents through research, training aviation personnel, protecting passengers and the general public, and designing safer aircraft and aviation infrastructure. The aviation industry is subject to significant regulations and oversight to reduce risks across all aspects of flight. Adverse weather conditions such as turbulence, thunderstorms, icing, and reduced visibility are also recognized as major contributing factors to aviation safety outcomes.

Aviation security is focused on protecting air travelers, aircraft and infrastructure from intentional harm or disruption, rather than unintentional mishaps.

Statistics

Evolution

Aviation is safer today than it has ever been. Modern commercial aviation boasts an accident rate of approximately 1 fatal accident per 16 million flights, far lower than historic numbers.

On December 14, 1903, the Wright Brothers conducted a test flight of their powered airplane from the slope of Big Kill Devil Hill in North Carolina. Upon takeoff, the airplane lifted about 15 feet off the ground, stalled, and crashed into the sand. Only three days later, on December 17, 1903, Wilbur's brother, Orville Wright flew the airplane for the world's first powered, sustained, and controlled heavier-than-air flight in history. Although the failed test flight on December 14 would be mostly forgotten in aviation, it remains one of the earliest recorded aviation accidents in history.

In the early years of air travel, accidents were exceedingly common. 1929 was named the year of "The Great Crash" due to the frequency of aircraft accidents that occurred during the year, with 24 fatal accidents officially reported. In 1928 and 1929, the overall accident rate was about 1 in every million miles (1.6 million kilometers) flown. In today's industry, that accident rate would translate to about 7,000 fatal accidents each year.

For the ten-year period 2002 to 2011, 0.6 fatal accidents happened per one million flights globally, 0.4 per million hours flown, 22.0 fatalities per one million flights or 12.7 per million hours flown.

From 310 million passengers in 1970, air transport had grown to 3,696 million in 2016, led by 823 million in the United States, then 488 million in China. In 2016, 19 fatal accidents involved civil airliners with more than 14 passengers. These accidents resulted in 325 fatalities, the second safest year ever after 2015 with 16 accidents and 2013 with 265 fatalities. For planes heavier than 5.7 metric tones, there were 34.9 million departures and 75 accidents worldwide with 7 of these fatal for 182 fatalities, the lowest since 2013 : 5.21 fatalities per million departures.

In 2017, there were 10 fatal airliner accidents, resulting in 44 occupant fatalities and 35 persons on the ground: the safest year ever for commercial aviation, both by the number of fatal accidents as well as in fatalities. By 2019, fatal accidents per million flights decreased 12 fold since 1970, from 6.35 to 0.51, and fatalities per trillion revenue passenger kilometre (RPK) decreased 81 fold from 3,218 to 40.

Typology

Runway safety represents 36% of accidents, ground safety 18% and loss of control in-flight 16%.

Loss of control inflight represents 35% of the fatal accidents, Controlled flight into terrain 21%, runway excursions 17%, system or component failure: 6%, Touchdown off the runway: 5%, Abnormal Runway Contact: 4% and fire: 2%.

Safety has improved from better aircraft design process, engineering and maintenance, the evolution of navigation aids, and safety protocols and procedures.

Transport comparisons

There are three main ways in which the risk of fatality in a certain mode of travel can be measured: (1) deaths per billion typical journeys taken, (2) deaths per billion hours traveled, and (3) deaths per billion kilometers traveled. The following table displays these statistics for the United Kingdom (1990–2000), and has been appended. (Note that aviation safety does not include travelling to the airport.)

The first two statistics are computed for typical travels by their respective forms of transport, so they cannot be used directly to compare risks related to different forms of transport in a particular travel "from A to B". For example, these statistics suggest that a typical flight from Los Angeles to New York would carry a larger risk factor than a typical car travel from home to office. However, car travel from Los Angeles to New York would not be typical; that journey would be as long as several dozen typical car travels, and thus the associated risk would be larger as well. Because the journey would take a much longer time, the overall risk associated with making this journey by car would be higher than making the same journey by air, even if each individual hour of car travel is less risky than each hour of flight.

For risks associated with long-range intercity travel, the most suitable statistic is the third one: deaths per billion kilometers. Still, this statistic can lose credence in situations where the availability of an air option makes an otherwise inconvenient journey possible.

Aviation industry insurers base their calculations on the deaths per journey statistic while the aviation industry itself generally uses the deaths per kilometre statistic in press releases.

Since 1997, the number of fatal air accidents has been no more than 1 for every 2,000,000,000 person-miles flown, and thus is one of the safest modes of transportation when measured by distance traveled.

The Economist notes that air travel is safer by distance travelled, but trains are as safe as planes. It also notes that cars are four times more hazardous for deaths per time travelled, and cars and trains are respectively three times and six times safer than planes by number of journeys taken.

Because the above figures are focused on providing a perspective to the realm of everyday transportation, air travel is taken to include only standard civil passenger aviation, as offered commercially to the general public. Military and special-purpose aircraft are excluded.

United States

Between 1990 and 2015, there were 1874 commuter and air taxi accidents in the U.S. of which 454 (24%) were fatal, resulting in 1,296 deaths, including 674 accidents (36%) and 279 fatalities (22%) in Alaska alone.

The number of deaths per passenger-mile on commercial airlines in the United States between 2000 and 2010 was about 0.2 deaths per 10 billion passenger-miles. For driving, the rate was 150 per 10 billion vehicle-miles for 2000: 750 times higher per mile than for flying in a commercial airplane.

There were no fatalities on large scheduled commercial airlines in the United States for over nine years, between the Colgan Air Flight 3407 crash in February 2009, and a catastrophic engine failure on Southwest Airlines Flight 1380 in April 2018.

Security

Another aspect of safety is protection from intentional harm or property damage, also known as security.

The terrorist attacks of 2001 are not counted as accidents. However, even if they were counted as accidents they would have added about 1 death per billion person-miles. Two months later, American Airlines Flight 587 crashed in New York City, killing 265 people, including 5 on the ground, causing 2001 to show a very high fatality rate. Even so, the rate that year including the attacks (estimated here to be about 4 deaths per billion person-miles), is safe compared to some other forms of transport when measured by distance traveled.

Developments

Before WWII

The first aircraft electrical or electronic device avionics system was Lawrence Sperry's autopilot, demonstrated in June 1914. The Transcontinental Airway System chain of beacons was built by the Commerce Department in 1923 to guide airmail flights.

Gyrocopters were developed by Juan de la Cierva to avoid stall and spin accidents, and for that invented cyclic and collective controls used by helicopters. The first flight of a gyrocopter was on 17 January 1923.

During the 1920s, the first laws were passed in the United States of America to regulate civil aviation, notably the Air Commerce Act of 1926, which required pilots and aircraft to be examined and licensed, for accidents to be properly investigated, and for the establishment of safety rules and navigation aids; under the Aeronautics Branch of the United States Department of Commerce (US DoC).

A network of aerial lighthouses was established in the United Kingdom and Europe during the 1920s and 1930s. Use of the lighthouses has declined with the advent of radio navigation aids such as non-directional beacon (NDB), VHF omnidirectional range (VOR), and distance measuring equipment (DME). The last operational aerial lighthouse in the United Kingdom is on top of the cupola over the RAF College main hall at RAF Cranwell.

One of the first aids for air navigation to be introduced in the United States in the late 1920s was airfield lighting, to assist pilots in making landings in poor weather or after dark. The Precision Approach Path Indicator (PAPI) was developed from this in the 1930s, indicating to the pilot the angle of descent to the airfield. This later became adopted internationally through the standards of the International Civil Aviation Organization (ICAO).