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Aviation safety is the study and practice of managing risks in aviation. This includes preventing
aviation accidents and incidents An aviation accident is defined by the Convention on International Civil Aviation Annex 13 as an occurrence associated with the operation of an aircraft, which takes place from the time any person boards the aircraft with the ''intention of fl ...
through research, educating air travel personnel, passengers and the general public, as well as the design of aircraft and aviation infrastructure. The aviation industry is subject to significant regulation and oversight. Aviation security is focused on protecting air travelers, aircraft and infrastructure from intentional harm or disruption, rather than unintentional mishaps.


Statistics


Evolution

In 1926 and 1927, there were a total of 24 fatal commercial airline crashes, a further 16 in 1928, and 51 in 1929 (killing 61 people), which remains the worst year on record at an accident rate of about 1 for every flown. Based on the current numbers flying, this would equate to 7,000 fatal incidents per 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, there were 19 fatal accidents of civil airliners of more than 14 passengers, resulting in 325 fatalities, the second safest year ever after 2015 with 16 accidents and 2013 with 265 fatalities. For planes heavier than 5.7 t, there were 34.9 million departures and 75 accidents worldwide with 7 of these fatal for 182 fatalities, the lowest since 2013 : 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 % of accidents, ground safety % and loss of control in-flight %. The main cause is human error. Safety has improved from better
aircraft design process The aircraft design process is a loosely defined method used to balance many competing and demanding requirements to produce an aircraft that is strong, lightweight, economical and can carry an adequate payload while being sufficiently reliable to ...
, engineering and maintenance, the evolution of navigation aids, and safety protocols and procedures.


Transport comparisons

There are three main ways in which risk of fatality of a certain mode of travel can be measured: Deaths per billion typical ''journeys'' taken, deaths per billion ''hours'' traveled, or deaths per billion ''kilometers'' traveled. The following table displays these statistics for the United Kingdom 1990–2000. Note that aviation safety does not include travelling to the airport. The first two statistics are computed for typical travels for 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: according to statistics, a typical flight from
Los Angeles Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the List of municipalities in California, largest city in the U.S. state, state of California and the List of United States cities by population, sec ...
to New York will carry a larger risk factor than a typical car travel from home to office. But a car travel from Los Angeles to New York would not be typical. It would be as large as several dozens of typical car travels, and associated risk will be larger as well. Because the journey would take a much longer time, the overall risk associated by making this journey by car will be higher than making the same journey by air, even if each individual hour of car travel can be less risky than an hour of flight. It is therefore important to use each statistic in a proper context. When it comes to a question about risks associated with a particular long-range travel from one city to another, the most suitable statistic is the third one, thus giving a reason to name air travel as the safest form of long-range transportation. However, if the availability of an air option makes an otherwise inconvenient journey possible, then this argument loses some of its force. 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 (e.g., 100 people flying a plane for counts as 100,000 person-miles, making it comparable with methods of transportation with different numbers of passengers, such as one person driving an
automobile A car or automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people instead of goods. The year 1886 is regarde ...
for , which is also 100,000 person-miles), and thus one of the safest modes of transportation when measured by distance traveled. The death per billion hours when skydiving assume a 6 minutes skydive (not accounting for the plane ascent). The death per billion journey when paragliding assume an average flight of 15 minutes, so 4 flights per hour.
The Economist ''The Economist'' is a British weekly newspaper printed in demitab format and published digitally. It focuses on current affairs, international business, politics, technology, and culture. Based in London, the newspaper is owned by The Eco ...
notes that air travel is safer by distance travelled, but trains are as safe as planes; and cars 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 An air taxi is a small commercial aircraft that makes short flights on demand. In 2001 air taxi operations were promoted in the United States by a NASA and aerospace industry study on the potential Small Aircraft Transportation System (SATS) ...
accidents in the U.S. of which 454 (%) were fatal, resulting in 1296 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 Colgan Air Flight 3407 (marketed as Continental Connection Flight 3407 under a codeshare agreement with Continental Airlines), was a scheduled passenger flight from Newark, New Jersey, to Buffalo, New York, which crashed on February 12, 2009. Th ...
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 Property damage (or cf. criminal damage in England and Wales) is damage or destruction of real or tangible personal property, caused by negligence, willful destruction, or act of nature. It is similar to vandalism and arson (destroying prop ...
, 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.


History


Before WWII

The first aircraft electrical or electronic device
avionics Avionics (a blend of ''aviation'' and ''electronics'') are the electronic systems used on aircraft. Avionic systems include communications, navigation, the display and management of multiple systems, and the hundreds of systems that are fit ...
system was
Lawrence Sperry Lawrence Burst Sperry (21 December 1892, Chicago, Illinois, United States – December 13, 1923, English Channel) was an aviation pioneer who invented the autopilot and the artificial horizon. Biography He was the third son of the gyrocompa ...
's
autopilot An autopilot is a system used to control the path of an aircraft, marine craft or spacecraft without requiring constant manual control by a human operator. Autopilots do not replace human operators. Instead, the autopilot assists the operator' ...
, demonstrated in June 1914. The
Transcontinental Airway System The Transcontinental Airway System was a navigational aid deployed in the United States during the 1920s. History In 1923, the United States Congress funded a sequential lighted airway along the transcontinental airmail route. The lighted ai ...
chain of beacons was built by the
Commerce Department The United States Department of Commerce is an executive department of the U.S. federal government concerned with creating the conditions for economic growth and opportunity. Among its tasks are gathering economic and demographic data for busin ...
in 1923 to guide
airmail Airmail (or air mail) is a mail transport service branded and sold on the basis of at least one leg of its journey being by air. Airmail items typically arrive more quickly than surface mail, and usually cost more to send. Airmail may be t ...
flights.
Gyrocopters An autogyro (from Ancient Greek, Greek and , "self-turning"), also known as a ''gyroplane'', is a type of rotorcraft that uses an unpowered rotor in free autorotation to develop lift (force), lift. Forward thrust is provided independently, by an ...
were developed by Juan de la Cierva to avoid stall and spin accidents, and for that invented cyclic and collective controls used by
helicopter A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes ...
s. The first flight of a gyrocopter was on 17 January 1923. During the 1920s, the first laws were passed in the US to regulate
civil aviation Civil aviation is one of two major categories of flying, representing all non-military and non-state aviation, both private and commercial. Most of the countries in the world are members of the International Civil Aviation Organization and work ...
, notably the
Air Commerce Act of 1926 The Air Commerce Act of 1926 created an Aeronautic Branch of the United States Department of Commerce. Its functions included testing and licensing of pilots, certification of aircraft and investigation of accidents. In 1934, the Aeronautics Bran ...
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 The United States Department of Commerce is an executive department of the U.S. federal government concerned with creating the conditions for economic growth and opportunity. Among its tasks are gathering economic and demographic data for bus ...
. 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 NDB (Non-directional beacon), VOR (VHF omnidirectional ranging) and DME (distance measuring equipment). The last operational aerial lighthouse in the United Kingdom is on top of the cupola over the RAF College main hall at
RAF Cranwell Royal Air Force Cranwell or more simply RAF Cranwell is a Royal Air Force station in Lincolnshire, England, close to the village of Cranwell, near Sleaford. Among other functions, it is home to the Royal Air Force College (RAFC), which tra ...
. One of the first aids for air navigation to be introduced in the US in the late 1920s was airfield lighting to assist pilots to make landings in poor weather or after dark. The
Precision Approach Path Indicator A precision approach path indicator (PAPI) is a visual aid that provides guidance information to help a pilot to acquire and maintain the correct approach (in the vertical plane) to an airport or an aerodrome. It is generally located on the left- ...
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 The International Civil Aviation Organization (ICAO, ) is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international a ...
(ICAO).
Jimmy Doolittle James Harold Doolittle (December 14, 1896 – September 27, 1993) was an American military general and aviation pioneer who received the Medal of Honor for his daring raid on Japan during World War II. He also made early coast-to-coast flights ...
developed Instrument rating and made his first "blind" flight in September 1929. The March 1931 wooden wing failure of a Transcontinental & Western Air Fokker F-10 carrying Knute Rockne, coach of the
University of Notre Dame The University of Notre Dame du Lac, known simply as Notre Dame ( ) or ND, is a private Catholic university, Catholic research university in Notre Dame, Indiana, outside the city of South Bend, Indiana, South Bend. French priest Edward Sorin fo ...
's football team, reinforced all-metal airframes and led to a more formal accident investigation system. On Sept. 4, 1933, a Douglas DC-1 test flight was conducted with one of the two engines shut down during the takeoff run, climbed to , and completed its flight, proving twin aircraft engine safety. With greater range than lights and weather immunity,
radio navigation Radio navigation or radionavigation is the application of radio frequencies to determine a position of an object on the Earth, either the vessel or an obstruction. Like radiolocation, it is a type of radiodetermination. The basic principles a ...
aids were first used in the 1930s, like the Australian Aeradio stations guiding transport flights, with a light beacon and a modified Lorenz beam transmitter (the German blind-landing equipment preceding the modern
instrument landing system In aviation, the instrument landing system (ILS) is a precision radio navigation system that provides short-range guidance to aircraft to allow them to approach a runway at night or in bad weather. In its original form, it allows an aircraft to ...
- ILS). ILS was first used by a scheduled flight to make a landing in a snowstorm at
Pittsburgh, Pennsylvania Pittsburgh ( ) is a city in the Commonwealth of Pennsylvania, United States, and the county seat of Allegheny County. It is the most populous city in both Allegheny County and Western Pennsylvania, the second-most populous city in Pennsylva ...
, in 1938, and a form of ILS was adopted by the ICAO for international use in 1949.


WWII and later

Hard
runway According to the International Civil Aviation Organization (ICAO), a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". Runways may be a man-made surface (often asphalt, concre ...
s were built worldwide for World War II to avoid waves and floating hazards plaguing
seaplane A seaplane is a powered fixed-wing aircraft capable of taking off and landing (alighting) on water.Gunston, "The Cambridge Aerospace Dictionary", 2009. Seaplanes are usually divided into two categories based on their technological characteri ...
s. Developed by the U.S. and introduced during World War II,
LORAN LORAN, short for long range navigation, was a hyperbolic radio navigation system developed in the United States during World War II. It was similar to the UK's Gee system but operated at lower frequencies in order to provide an improved range u ...
replaced the sailors' less reliable
compass A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself wit ...
and celestial navigation over water and survived until it was replaced by the
Global Positioning System The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
. Following the development of radar in World War II, it was deployed as a landing aid for civil aviation in the form of ground-controlled approach (GCA) systems then as the airport surveillance radar as an aid to
air traffic control Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled airs ...
in the 1950s. A number of ground-based
weather radar Weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.). Modern weather radars are mostly pulse- ...
systems can detect areas of severe turbulence. A modern
Honeywell Honeywell International Inc. is an American publicly traded, multinational conglomerate corporation headquartered in Charlotte, North Carolina. It primarily operates in four areas of business: aerospace, building technologies, performance ma ...
Intuvue weather system visualizes weather patterns up to away.
Distance measuring equipment In aviation, distance measuring equipment (DME) is a radio navigation technology that measures the slant range (distance) between an aircraft and a ground station by timing the propagation delay of radio signals in the frequency band betwee ...
(DME) in 1948 and
VHF omnidirectional range Very high frequency omnirange station (VOR) is a type of short-range radio navigation system for aircraft, enabling aircraft with a receiving unit to determine its position and stay on course by receiving radio signals transmitted by a network ...
(VOR) stations became the main route navigation means during the 1960s, superseding the low frequency radio ranges and the
non-directional beacon A non-directional beacon (NDB) or non-directional radio beacon is a radio beacon which does not include directional information. Radio beacons are radio transmitters at a known location, used as an aviation or marine navigational aid. NDB are i ...
(NDB): the ground-based VOR stations were often co-located with DME transmitters and the pilots could establish their bearing and distance to the station. With the arrival of
Wide Area Augmentation System The Wide Area Augmentation System (WAAS) is an air navigation aid developed by the Federal Aviation Administration to augment the Global Positioning System (GPS), with the goal of improving its accuracy, integrity, and availability. Essentia ...
(WAAS), satellite navigation has become accurate enough for altitude as well as positioning use, and is being used increasingly for instrument approaches as well as en-route navigation. However, because the GPS constellation is a
single point of failure A single point of failure (SPOF) is a part of a system that, if it fails, will stop the entire system from working. SPOFs are undesirable in any system with a goal of high availability or reliability, be it a business practice, software appl ...
, on-board
Inertial Navigation System An inertial navigation system (INS) is a navigation device that uses motion sensors (accelerometers), rotation sensors ( gyroscopes) and a computer to continuously calculate by dead reckoning the position, the orientation, and the velocity (dir ...
(INS) or ground-based navigation aids are still required for backup. In 2017,
Rockwell Collins Rockwell Collins was a multinational corporation headquartered in Cedar Rapids, Iowa, providing avionics and information technology systems and services to government agencies and aircraft manufacturers. It was formed when the Collins Radio Comp ...
reported it had become more costly to certify than to develop a system, from 75% engineering and 25% certification in past years. It calls for a global harmonization between certifying authorities to avoid redundant engineering and certification tests rather than recognizing the others approval and validation. Groundings of entire classes of aircraft out of equipment safety concerns is unusual, but this has occurred to the
de Havilland Comet The de Havilland DH.106 Comet was the world's first commercial jet airliner. Developed and manufactured by de Havilland in the United Kingdom, the Comet 1 prototype first flew in 1949. It featured an aerodynamically clean design with four ...
in 1954 after multiple crashes due to metal fatigue and hull failure, the
McDonnell Douglas DC-10 The McDonnell Douglas DC-10 is an American trijet wide-body aircraft manufactured by McDonnell Douglas. The DC-10 was intended to succeed the DC-8 for long- range flights. It first flew on August 29, 1970; it was introduced on August 5, 197 ...
in 1979 after the crash of American Airlines Flight 191 due to engine loss, the
Boeing 787 Dreamliner The Boeing 787 Dreamliner is an American wide-body jet airliner developed and manufactured by Boeing Commercial Airplanes. After dropping its unconventional Sonic Cruiser project, Boeing announced the conventional 7E7 on January 29, 2003, ...
in 2013 after its battery problems, and the Boeing 737 MAX in 2019 after two crashes preliminarily tied to a flight control system.


Aviation safety hazards


Unapproved parts

Parts manufactured without an aviation authority's approval are described as "unapproved". Unapproved parts include inferior counterfeits, those used beyond their time limits, those that were previously approved but not properly returned to service, those with fraudulent labels, production overruns that were not sold with the agency's permission, and those that are untraceable. Unapproved faulty parts have caused hundreds of incidents and crashes, some fatal, including about 24 crashes between 2010 and 2016.


Foreign object debris

Foreign object debris (FOD) includes items left in the aircraft structure during manufacture/repairs, debris on the runway and solids encountered in flight (e.g. hail and dust). Such items can damage engines and other parts of the aircraft. In 2000, Air France Flight 4590 crashed after hitting a part that had fallen from a departing Continental Airlines DC-10.


Misleading information and lack of information

A pilot misinformed by a printed document (manual, map, etc.), reacting to a faulty instrument or indicator (in the cockpit or on the ground), or following inaccurate instructions or information from flight or ground control can lose
situation awareness Situational awareness or situation awareness (SA) is the perception of environmental elements and events with respect to time or space, the comprehension of their meaning, and the projection of their future status. An alternative definition is tha ...
, or make errors, and accidents or near misses may result. The crash of
Air New Zealand Flight 901 The Mount Erebus disaster occurred on 28 November 1979 when Air New Zealand Flight 901 (TE-901) flew into Mount Erebus on Ross Island, Antarctica, killing all 237 passengers and 20 crew on board. Air New Zealand had been operating scheduled A ...
was a result of receiving and interpreting incorrect coordinates, which caused the pilots to inadvertently fly into a mountain.


Lightning

Boeing studies showed that airliners are struck by
lightning Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions, both in the atmosphere or with one on the ground, temporarily neutralize themselves, causing the instantaneous release of an avera ...
twice per year on average; aircraft withstand typical lightning strikes without damage. The dangers of more powerful positive lightning were not understood until the destruction of a
glider Glider may refer to: Aircraft and transport Aircraft * Glider (aircraft), heavier-than-air aircraft primarily intended for unpowered flight ** Glider (sailplane), a rigid-winged glider aircraft with an undercarriage, used in the sport of glidin ...
in 1999. It has since been suggested that positive lightning might have caused the crash of Pan Am Flight 214 in 1963. At that time, aircraft were not designed to withstand such strikes because their existence was unknown. The 1985 standard in force in the US at the time of the glider crash, Advisory Circular AC 20-53A, was replaced by Advisory Circular AC 20-53B in 2006. However, it is unclear whether adequate protection against positive lightning was incorporated. The effects of typical lightning on traditional metal-covered aircraft are well understood and serious damage from a lightning strike on an airplane is rare. The
Boeing 787 Dreamliner The Boeing 787 Dreamliner is an American wide-body jet airliner developed and manufactured by Boeing Commercial Airplanes. After dropping its unconventional Sonic Cruiser project, Boeing announced the conventional 7E7 on January 29, 2003, ...
of which the exterior is
carbon-fiber-reinforced polymer Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...
received no damage from a lightning strike during testing.


Ice and snow

Ice and
snow Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout ...
can be major factors in airline accidents. In 2005,
Southwest Airlines Flight 1248 Southwest Airlines Flight 1248 was a scheduled passenger flight from Baltimore, Maryland, to Chicago, Illinois, continuing on to Salt Lake City, Utah, and then to Las Vegas, Nevada. On December 8, 2005, the airplane slid off a runway at Chica ...
slid off the end of a
runway According to the International Civil Aviation Organization (ICAO), a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". Runways may be a man-made surface (often asphalt, concre ...
after landing in heavy snow conditions, killing one child on the ground. Even a small amount of icing or coarse frost can greatly impair the ability of a wing to develop adequate
lift Lift or LIFT may refer to: Physical devices * Elevator, or lift, a device used for raising and lowering people or goods ** Paternoster lift, a type of lift using a continuous chain of cars which do not stop ** Patient lift, or Hoyer lift, mobil ...
, which is why regulations prohibit ice, snow or even frost on the wings or tail, prior to takeoff.
Air Florida Flight 90 Air Florida Flight 90 was a scheduled U.S. domestic passenger flight operated by Air Florida from Washington National Airport (now Ronald Reagan Washington National Airport) to Fort Lauderdale–Hollywood International Airport, with an interme ...
crashed on takeoff in 1982, as a result of ice/snow on its wings. An accumulation of ice during flight can be catastrophic, as evidenced by the loss of control and subsequent crashes of American Eagle Flight 4184 in 1994, and
Comair Flight 3272 Comair Flight 3272 was a Comair flight from Cincinnati to Detroit on Thursday, January 9, 1997. While on approach for landing, the Embraer EMB 120 Brasilia aircraft crashed nose-down southwest of Detroit Metropolitan Wayne County Airport at ...
in 1997. Both aircraft were
turboprop A turboprop is a turbine engine that drives an aircraft propeller. A turboprop consists of an intake, reduction gearbox, compressor, combustor, turbine, and a propelling nozzle. Air enters the intake and is compressed by the compressor. ...
airliners, with straight wings, which tend to be more susceptible to inflight ice accumulation, than are swept-wing jet airliners. Airlines and airports ensure that aircraft are properly de-iced before
takeoff Takeoff is the phase of flight in which an aerospace vehicle leaves the ground and becomes airborne. For aircraft traveling vertically, this is known as liftoff. For aircraft that take off horizontally, this usually involves starting with a ...
whenever the weather involves
icing conditions In aviation, icing conditions are atmospheric conditions that can lead to the formation of water ice on an aircraft. Ice accretion and accumulation can affect the external surfaces of an aircraft – in which case it is referred to as ''airframe ...
. Modern airliners are designed to prevent ice buildup on
wing A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is e ...
s,
engines An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power g ...
, and tails (
empennage The empennage ( or ), also known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow.Crane, Dale: ''Dictionary of Aeronautical Terms, third e ...
) by either routing heated air from jet engines through the
leading edge The leading edge of an airfoil surface such as a wing is its foremost edge and is therefore the part which first meets the oncoming air.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 305. Aviation Supplies & Academics, ...
s of the wing, and inlets, or on slower aircraft, by use of inflatable rubber "
boots A boot is a type of footwear. Boot or Boots may also refer to: Businesses * Boot Inn, Chester, Cheshire, England * Boots (company), a high-street pharmacy chain and manufacturer of pharmaceuticals in the United Kingdom * The Boot, Cromer St ...
" that expand to break off any accumulated ice. Airline flight plans require airline dispatch offices to monitor the progress of weather along the routes of their flights, helping the pilots to avoid the worst of inflight icing conditions. Aircraft can also be equipped with an ice detector in order to warn pilots to leave unexpected ice accumulation areas, before the situation becomes critical.
Pitot tube A pitot ( ) tube (pitot probe) measures fluid flow velocity. It was invented by a French engineer, Henri Pitot, in the early 18th century, and was modified to its modern form in the mid-19th century by a French scientist, Henry Darcy. It ...
s in modern airplanes and helicopters have been provided with the function of "Pitot Heating" to prevent accidents like
Air France Flight 447 Air France Flight 447 (AF447 or AFR447) was a scheduled international passenger flight from Rio de Janeiro, Brazil, to Paris, France. On 1 June 2009, inconsistent airspeed indications led to the pilots inadvertently stalling the Airbus A330 ser ...
caused by the pitot tube freezing and giving false readings.


Wind shear or microburst

A
wind shear Wind shear (or windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizont ...
is a change in wind speed and/or direction over a relatively short distance in the atmosphere. A microburst is a localized column of sinking air that drops down in a thunderstorm. Both of these are potential weather threats that may cause an aviation accident. Strong outflow from thunderstorms causes rapid changes in the three-dimensional wind velocity just above ground level. Initially, this outflow causes a headwind that increases airspeed, which normally causes a pilot to reduce engine power if they are unaware of the wind shear. As the aircraft passes into the region of the downdraft, the localized headwind diminishes, reducing the aircraft's airspeed and increasing its sink rate. Then, when the aircraft passes through the other side of the downdraft, the headwind becomes a tailwind, reducing lift generated by the wings, and leaving the aircraft in a low-power, low-speed descent. This can lead to an accident if the aircraft is too low to effect a recovery before ground contact. Between 1964 and 1985, wind shear directly caused or contributed to 26 major civil transport aircraft accidents in the U.S. that led to 620 deaths and 200 injuries.


Engine failure

An engine may fail to function because of
fuel starvation In an internal combustion engine, fuel starvation is the failure of the fuel system to supply sufficient fuel to allow the engine to run properly, for example due to blockage, vapor lock, contamination by water, malfunction of the fuel pump or in ...
(e.g.
British Airways Flight 38 British Airways Flight 38 was a scheduled international passenger flight from Beijing Capital International Airport in Beijing, China, to London Heathrow Airport in London, United Kingdom, an trip. On 17 January 2008, the Boeing 777-200ER airc ...
),
fuel exhaustion In an internal combustion engine, fuel starvation is the failure of the fuel system to supply sufficient fuel to allow the engine to run properly, for example due to blockage, vapor lock, contamination by water, malfunction of the fuel pump or in ...
(e.g. Air Canada Flight 143),
foreign object damage In aviation and aerospace, foreign object debris (FOD), is any particle or substance, alien to an aircraft or system, which could potentially cause damage. External FOD hazards include bird strikes, hail, ice, sandstorms, ash-clouds or obje ...
(e.g.
US Airways Flight 1549 US Airways Flight 1549 was a regularly scheduled US Airways flight from New York City (LaGuardia Airport), to Charlotte and Seattle, in the United States. On January 15, 2009, the Airbus A320 serving the flight struck a flock of birds short ...
), mechanical failure due to
metal fatigue In materials science, fatigue is the initiation and propagation of cracks in a material due to cyclic loading. Once a fatigue crack has initiated, it grows a small amount with each loading cycle, typically producing striations on some parts o ...
(e.g.
Kegworth air disaster The Kegworth air disaster occurred when British Midland Airways Flight 092, a Boeing 737-400, crashed onto the motorway embankment between the M1 motorway and A453 road near Kegworth, Leicestershire, England, while attempting to make an emer ...
, El Al Flight 1862, China Airlines Flight 358), mechanical failure due to improper maintenance (e.g. American Airlines Flight 191), mechanical failure caused by an original manufacturing defect in the engine (e.g.
Qantas Flight 32 Qantas Flight 32 was a regularly scheduled passenger flight from London to Sydney via Singapore. On 4 November 2010, the aircraft operating the route, an Airbus A380, suffered an uncontained failure in one of its four Rolls-Royce Trent 900 eng ...
,
United Airlines Flight 232 United Airlines Flight 232 was a regularly scheduled United Airlines flight from Stapleton International Airport in Denver to O'Hare International Airport in Chicago, continuing to Philadelphia International Airport. On July 19, 1989, the DC ...
,
Delta Air Lines Flight 1288 Delta Air Lines Flight 1288 was a regularly scheduled flight from Pensacola, Florida, to Atlanta, Georgia. On July 6, 1996, the aircraft serving the flight, a McDonnell Douglas MD-88, was on takeoff roll from Runway 17 at Pensacola when it exp ...
), and pilot error (e.g. Pinnacle Airlines Flight 3701). In a multi-engine aircraft, failure of a single engine usually results in a precautionary landing being performed, for example landing at a
diversion airport Diversion airports are airports capable of handling a particular ETOPS ETOPS () is an acronym for ''Extended-range Twin-engine Operations Performance Standards''—a special part of flight rules for one-engine-inoperative flight conditions. The I ...
instead of continuing to the intended destination. Failure of a second engine (e.g.
US Airways Flight 1549 US Airways Flight 1549 was a regularly scheduled US Airways flight from New York City (LaGuardia Airport), to Charlotte and Seattle, in the United States. On January 15, 2009, the Airbus A320 serving the flight struck a flock of birds short ...
) or damage to other aircraft systems caused by an uncontained engine failure (e.g.
United Airlines Flight 232 United Airlines Flight 232 was a regularly scheduled United Airlines flight from Stapleton International Airport in Denver to O'Hare International Airport in Chicago, continuing to Philadelphia International Airport. On July 19, 1989, the DC ...
) may, if an
emergency landing An emergency landing is a premature landing made by an aircraft in response to an emergency involving an imminent or ongoing threat to the safety and operation of the aircraft, or involving a sudden need for a passenger or crew on board to term ...
is not possible, result in the aircraft crashing.


Structural failure of the aircraft

Examples of failure of aircraft structures caused by
metal fatigue In materials science, fatigue is the initiation and propagation of cracks in a material due to cyclic loading. Once a fatigue crack has initiated, it grows a small amount with each loading cycle, typically producing striations on some parts o ...
include the
de Havilland Comet The de Havilland DH.106 Comet was the world's first commercial jet airliner. Developed and manufactured by de Havilland in the United Kingdom, the Comet 1 prototype first flew in 1949. It featured an aerodynamically clean design with four ...
accidents (1950s) and
Aloha Airlines Flight 243 Aloha Airlines Flight 243 (IATA: AQ243, ICAO: AAH243) was a scheduled Aloha Airlines flight between Hilo and Honolulu in Hawaii. On April 28, 1988, a Boeing 737-297 serving the flight suffered extensive damage after an explosive decompression i ...
(1988). Improper repair procedures can also cause structural failures include
Japan Airlines Flight 123 Japan Air Lines Flight 123 (JAL123) () was a scheduled domestic Japan Air Lines passenger flight from Haneda Airport in Tokyo to Itami International Airport in Osaka. On August 12, 1985, the Boeing 747SR operating this flight suffered a sudden ...
(1985) and China Airlines Flight 611 (2002). Now that the subject is better understood, rigorous inspection and nondestructive testing procedures are in place.
Composite material A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or ...
s consist of layers of
fiber Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorpora ...
s embedded in a
resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on n ...
matrix. In some cases, especially when subjected to cyclic stress, the layers of the material separate from each other ( delaminate) and lose strength. As the failure develops inside the material, nothing is shown on the surface; instrument methods (often
ultrasound Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies ...
-based) have to be used to detect such a material failure. In the 1940s several
Yakovlev Yak-9 The Yakovlev Yak-9 (russian: Яковлев Як-9) is a single-engine, single-seat multipurpose fighter aircraft used by the Soviet Union and its allies during World War II and the early Cold War. It was a development of the robust and successf ...
s experienced delamination of plywood in their construction.


Stalling

Stalling an aircraft (increasing the angle of attack to a point at which the wings fail to produce enough
lift Lift or LIFT may refer to: Physical devices * Elevator, or lift, a device used for raising and lowering people or goods ** Paternoster lift, a type of lift using a continuous chain of cars which do not stop ** Patient lift, or Hoyer lift, mobil ...
) is dangerous and can result in a crash if the pilot fails to make a timely correction. Devices to warn the pilot when the aircraft's speed is decreasing close to the stall speed include stall warning horns (now standard on virtually all powered aircraft),
stick shaker A stick shaker is a mechanical device designed to rapidly and noisily vibrate the control yoke (the "stick") of an aircraft, warning the flight crew that an imminent aerodynamic stall has been detected. It is typically present on the majority of ...
s, and voice warnings. Most stalls are a result of the pilot allowing the airspeed to be too slow for the particular weight and configuration at the time. Stall speed is higher when ice or frost has attached to the wings and/or tail stabilizer. The more severe the icing, the higher the stall speed, not only because smooth airflow over the wings becomes increasingly more difficult, but also because of the added weight of the accumulated ice. Crashes caused by a full stall of the airfoils include: *
British European Airways Flight 548 British European Airways Flight 548 was a scheduled passenger flight from London Heathrow to Brussels that crashed near Staines, Surrey, England, soon after take-off on 18 June 1972, killing all 118 people on board. The accident became known a ...
(1972) * United Airlines Flight 553 (1972) * Aeroflot Flight 7425 (1985) *
Arrow Air Flight 1285 Arrow Air Flight 1285R was an international charter flight carrying U.S. troops from Cairo, Egypt, to their home base in Fort Campbell, Kentucky, via Cologne, West Germany, and Gander, Newfoundland. On the morning of Thursday, 12 December 1985 ...
(1985) *
Northwest Airlines Flight 255 On August 16, 1987 a McDonnell Douglas MD-80#MD-82, McDonnell Douglas MD-82, operating as Northwest Airlines Flight 255, crashed shortly after takeoff from Detroit Metropolitan Airport, about 8:46 pm Eastern Time Zone, EDT (00:46 UTC Augus ...
(1987) * The
Paul Wellstone Paul David Wellstone (July 21, 1944 – October 25, 2002) was an American academic, author, and politician who represented Minnesota in the United States Senate from 1991 until he was killed in a plane crash near Eveleth, Minnesota, in 2002. A ...
crash (2002) *
Colgan Air Flight 3407 Colgan Air Flight 3407 (marketed as Continental Connection Flight 3407 under a codeshare agreement with Continental Airlines), was a scheduled passenger flight from Newark, New Jersey, to Buffalo, New York, which crashed on February 12, 2009. Th ...
(2009) *
Turkish Airlines Flight 1951 Turkish Airlines Flight 1951 (also known as the Poldercrash or the Schiphol Polderbaan incident) was a passenger flight that crashed during landing at Amsterdam Schiphol Airport, the Netherlands, on 25 February 2009, resulting in the deaths of ...
crash (2009) *
Air France Flight 447 Air France Flight 447 (AF447 or AFR447) was a scheduled international passenger flight from Rio de Janeiro, Brazil, to Paris, France. On 1 June 2009, inconsistent airspeed indications led to the pilots inadvertently stalling the Airbus A330 ser ...
(2009)


Fire

Safety regulations control aircraft materials and the requirements for automated fire safety systems. Usually these requirements take the form of required tests. The tests measure
flammability A combustible material is something that can burn (i.e., ''combust'') in air. A combustible material is flammable if it ignites easily at ambient temperatures. In other words, a combustible material ignites with some effort and a flammable mat ...
of materials and
toxicity Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subs ...
of
smoke Smoke is a suspension of airborne particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-produc ...
. When the tests fail, it is on a prototype in an engineering laboratory rather than in an aircraft. Fire and its toxic smoke have been the cause of accidents. An electrical fire on Air Canada Flight 797 in 1983 caused the deaths of 23 of the 46 passengers, resulting in the introduction of floor level lighting to assist people to evacuate a smoke-filled aircraft. In 1985, a fire on the runway caused the loss of 55 lives, 48 from the effects of incapacitating and subsequently lethal toxic gas and smoke in the
British Airtours Flight 28M British Airtours Flight 28M (also known as Flight 328) was an international passenger flight which caught fire before takeoff at Manchester Airport, England on 22 August 1985 with the loss of 55 lives. It was en route to Corfu International A ...
accident which raised serious concerns relating to survivability – something that had not been studied in such detail. The swift incursion of the fire into the fuselage and the layout of the aircraft impaired passengers' ability to evacuate, with areas such as the forward galley area becoming a bottle-neck for escaping passengers, with some dying very close to the exits. Much research into evacuation and cabin and seating layouts was carried out at Cranfield Institute to try to measure what makes a good evacuation route, which led to the seat layout by
Overwing exits Overwing exits are found on passenger aircraft to provide a means of evacuation onto the wing, where passengers continue off the trailing edge, either by sliding down the extended flaps or by using an evacuation slide that deploys when the exit ...
being changed by mandate and the examination of evacuation requirements relating to the design of galley areas. The use of smoke hoods or misting systems were also examined although both were rejected. South African Airways Flight 295 was lost in the Indian Ocean in 1987 after an in-flight fire in the cargo hold could not be suppressed by the crew. The cargo holds of most airliners are now equipped with automated halon fire extinguishing systems to combat a fire that might occur in the baggage holds. In May 1996,
ValuJet Flight 592 ValuJet Airlines Flight 592 was a regularly scheduled flight from Miami International Airport to Hartsfield–Jackson Atlanta International Airport. On May 11, 1996, the ValuJet Airlines McDonnell Douglas DC-9 operating the route crashed into t ...
crashed into the Florida
Everglades The Everglades is a natural region of tropical wetlands in the southern portion of the U.S. state of Florida, comprising the southern half of a large drainage basin within the Neotropical realm. The system begins near Orlando with the Kissim ...
a few minutes after takeoff because of a fire in the forward cargo hold. All 110 people on board were killed. At one time, fire fighting
foam path A foam path is the now-discouraged aviation safety practice of spreading a layer of fire suppression foam on an airport runway prior to an emergency landing. Originally, it was thought this would prevent fires, but the practice is no longer recomme ...
s were laid down before an emergency landing, but the practice was considered only marginally effective, and concerns about the depletion of fire fighting capability due to pre-foaming led the United States FAA to withdraw its recommendation in 1987. One possible cause of fires in airplanes is wiring problems that involve intermittent faults, such as wires with breached insulation touching each other, having water dripping on them, or short circuits. Notable was Swissair Flight 111 in 1998 due to an arc in the wiring of IFE which ignite flammable MPET insulation. These are difficult to detect once the aircraft is on the ground. However, there are methods, such as spread-spectrum time-domain reflectometry, that can feasibly test live wires on aircraft during flight.


Bird strike

''Bird strike'' is an aviation term for a collision between a bird and an aircraft. Fatal accidents have been caused by both engine failure following bird ingestion and bird strikes breaking cockpit windshields. Jet engines have to be designed to withstand the ingestion of birds of a specified weight and number and to not lose more than a specified amount of thrust. The weight and numbers of birds that can be ingested without hazarding the safe flight of the aircraft are related to the engine intake area. The hazards of ingesting birds beyond the "designed-for" limit were shown on
US Airways Flight 1549 US Airways Flight 1549 was a regularly scheduled US Airways flight from New York City (LaGuardia Airport), to Charlotte and Seattle, in the United States. On January 15, 2009, the Airbus A320 serving the flight struck a flock of birds short ...
when the aircraft struck Canada geese. The outcome of an ingestion event and whether it causes an accident, be it on a small fast plane, such as military jet fighters, or a large transport, depends on the number and weight of birds and where they strike the fan blade span or the nose cone. Core damage usually results with impacts near the blade root or on the nose cone. The highest risk of a bird strike occurs during takeoff and
landing Landing is the last part of a flight, where a flying animal, aircraft, or spacecraft returns to the ground. When the flying object returns to water, the process is called alighting, although it is commonly called "landing", "touchdown" or ...
in the vicinity of
airport An airport is an aerodrome with extended facilities, mostly for commercial air transport. Airports usually consists of a landing area, which comprises an aerially accessible open space including at least one operationally active surfa ...
s, and during low-level flying, for example by military aircraft, crop dusters and helicopters. Some airports use active countermeasures, including a person with a shotgun, playing recorded sounds of predators through loudspeakers, or employing falconers. Poisonous grass can be planted that is not palatable to birds, nor to insects that attract insectivorous birds. Passive countermeasures involve sensible land-use management, avoiding conditions attracting flocks of birds to the area (e.g. landfills). Another tactic found effective is to let the grass at the airfield grow taller (to approximately ) as some species of birds won't land if they cannot see one another.


Human factors

Human factors Human factors and ergonomics (commonly referred to as human factors) is the application of psychological and physiological principles to the engineering and design of products, processes, and systems. Four primary goals of human factors learnin ...
, including
pilot error Pilot error generally refers to an accident in which an action or decision made by the pilot was the cause or a contributing factor that led to the accident, but also includes the pilot's failure to make a correct decision or take proper a ...
, are another potential set of factors, and currently the factor most commonly found in aviation accidents. Much progress in applying human factors analysis to improving aviation safety was made around the time of
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
by such pioneers as
Paul Fitts Paul Morris Fitts Jr. (May 6, 1912 – May 2, 1965) was a psychologist at the Ohio State University (later at the University of Michigan). He developed a model of human movement, Fitts's law, based on rapid, aimed movement, which went on to beco ...
and Alphonse Chapanis. However, there has been progress in safety throughout the history of aviation, such as the development of the pilot's checklist in 1937. CRM, or
Crew Resource Management Crew resource management or cockpit resource management (CRM)Diehl, Alan (2013) "Air Safety Investigators: Using Science to Save Lives-One Crash at a Time." Xlibris Corporation. . http://www.prweb.com/releases/DrAlanDiehl/AirSafetyInvestigators/ ...
, is a technique that makes use of the experience and knowledge of the complete flight crew to avoid dependence on just one crew member, and to improve pilot decision making. Pilot error and improper communication are often factors in the
collision In physics, a collision is any event in which two or more bodies exert forces on each other in a relatively short time. Although the most common use of the word ''collision'' refers to incidents in which two or more objects collide with great fo ...
of aircraft. This can take place
in the air IN, In or in may refer to: Places * India (country code IN) * Indiana, United States (postal code IN) * Ingolstadt, Germany (license plate code IN) * In, Russia, a town in the Jewish Autonomous Oblast Businesses and organizations * Independ ...
(1978
Pacific Southwest Airlines Pacific Southwest Airlines (PSA) was a regional U.S. airline headquartered in San Diego, California, that operated from 1949 to 1998. It was the first large discount airline in the United States. PSA called itself "The World's Friendliest Airl ...
Flight 182) ( TCAS) or on the ground (1977 Tenerife disaster) ( RAAS). The barriers to effective communication have internal and external factors. The ability of the flight crew to maintain
situation awareness Situational awareness or situation awareness (SA) is the perception of environmental elements and events with respect to time or space, the comprehension of their meaning, and the projection of their future status. An alternative definition is tha ...
is a critical human factor in air safety. Human factors training is available to general aviation pilots and called single pilot resource management training. Failure of the pilots to properly monitor the flight instruments caused the crash of
Eastern Air Lines Flight 401 Eastern Air Lines Flight 401 was a scheduled flight from New York JFK to Miami. Shortly before midnight on December 29, 1972, the Lockheed L-1011-1 TriStar crashed into the Florida Everglades, causing 101 total fatalities. Three of the 4 cockpi ...
in 1972.
Controlled flight into terrain In aviation, a controlled flight into terrain (CFIT; usually ) is an accident in which an airworthy aircraft, under pilot control, is unintentionally flown into the ground, a mountain, a body of water or an obstacle. In a typical CFIT scenario, ...
(CFIT), and error during take-off and landing can have catastrophic consequences, for example causing the crash of Prinair Flight 191 on landing, also in 1972.


Pilot fatigue

The
International Civil Aviation Organization The International Civil Aviation Organization (ICAO, ) is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international a ...
(ICAO) defines fatigue as "A physiological state of reduced mental or physical performance capability resulting from sleep loss or extended wakefulness, circadian phase, or workload." The phenomenon places great risk on the crew and passengers of an airplane because it significantly increases the chance of
pilot error Pilot error generally refers to an accident in which an action or decision made by the pilot was the cause or a contributing factor that led to the accident, but also includes the pilot's failure to make a correct decision or take proper a ...
. Fatigue is particularly prevalent among pilots because of "unpredictable work hours, long duty periods, circadian disruption, and insufficient sleep". These factors can occur together to produce a combination of sleep deprivation, circadian rhythm effects, and 'time-on task' fatigue. Regulators attempt to mitigate fatigue by limiting the number of hours pilots are allowed to fly over varying periods of time. Experts in aviation fatigue often find that these methods fall short of their goals.


Piloting while intoxicated

Rarely, flight crew members are arrested or subject to disciplinary action for being intoxicated on the job. In 1990, three
Northwest Airlines Northwest Airlines Corp. (NWA) was a major American airline founded in 1926 and absorbed into Delta Air Lines, Inc. by a merger. The merger, approved on October 29, 2008, made Delta the largest airline in the world until the American Airlines ...
crew members were sentenced to jail for flying while drunk. In 2001, Northwest fired a pilot who failed a
breathalyzer A breathalyzer or breathalyser (a portmanteau of ''breath'' and ''analyzer/analyser'') is a device for estimating blood alcohol content (BAC), or to detect viruses or diseases from a breath sample. The name is a genericized trademark of the Br ...
test after a flight. In July 2002, both pilots of
America West Airlines Flight 556 America West Airlines Flight 556 was a regularly scheduled flight from Miami, Florida, to Phoenix, Arizona, operated by an America West Airlines Airbus A319. On July 1, 2002, the plane was ordered back to the terminal after the pilots were susp ...
were arrested just before they were scheduled to fly because they had been drinking alcohol. The pilots were fired and the FAA revoked their pilot licenses. At least one fatal airliner accident involving drunk pilots occurred when Aero Flight 311 crashed at Koivulahti, Finland, killing all 25 on board in 1961.


Pilot suicide and murder

There have been rare instances of suicide by pilots. Although most air crew are screened for psychological fitness, a very few authorized pilots have flown acts of suicide and even mass murder. In 1982,
Japan Airlines Flight 350 was a McDonnell Douglas DC-8-61, registered ''JA8061'', on a domestic scheduled passenger flight from Fukuoka, Fukuoka Prefecture, to Tokyo in Japan. The airplane crashed 9 February 1982 on approach to Haneda Airport in Tokyo Bay, resulting ...
crashed while on approach to the Tokyo Haneda Airport, killing 24 of the 174 on board. The official investigation found the mentally ill captain had attempted suicide by placing the inboard engines into reverse thrust, while the aircraft was close to the runway. The first officer did not have enough time to countermand before the aircraft stalled and crashed. In 1997, SilkAir Flight 185 suddenly went into a high dive from its cruising altitude. The speed of the dive was so high that the aircraft began to break apart before it finally crashed near Palembang, Sumatra. After three years of investigation, the Indonesian authorities declared that the cause of the accident could not be determined. However, the US NTSB concluded that deliberate suicide by the captain was the only reasonable explanation. In the case of
EgyptAir Flight 990 EgyptAir Flight 990 (MS990/MSR990) was a regularly scheduled flight from Los Angeles International Airport to Cairo International Airport, with a stop at John F. Kennedy International Airport, New York City. On October 31, 1999, the Boeing 767-3 ...
, it appears that the first officer deliberately crashed into the Atlantic Ocean while the captain was away from his station in 1999 off Nantucket, Massachusetts. Crew involvement is one of the speculative theories in the disappearance of Malaysia Airlines Flight 370 on 8 March 2014. In 2015, on March 24,
Germanwings Flight 9525 Germanwings Flight 9525 PDF of the English translation of the final report and thoriginal French version(which the BEA notes on PDF p. 2/110 of the English PDF is the primary work of reference) was a scheduled international passenger flight fr ...
(an Airbus A320-200) crashed northwest of Nice, in the French Alps, after a constant descent that began one minute after the last routine contact with air traffic control and shortly after the aircraft had reached its assigned cruise altitude. All 144 passengers and six crew members were killed. The crash was intentionally caused by the co-pilot, Andreas Lubitz. Having been declared "unfit to work" without telling his employer, Lubitz reported for duty, and during the flight locked the Captain out of the flightdeck. In response to the incident and the circumstances of Lubitz's involvement, aviation authorities in Canada, New Zealand, Germany and Australia implemented new regulations that require two authorized personnel to be present in the cockpit at all times. Three days after the incident the European Aviation Safety Agency issued a temporary recommendation for airlines to ensure that at least two crew members, including at least one pilot, are in the cockpit at all times of the flight. Several airlines announced they had already adopted similar policies voluntarily.


Deliberate aircrew inaction

Inaction, omission (law), omission, failure to act as required, willful disregard of safety procedures, disdain for rules, unjustifiable risk-taking by pilots have also led to Aviation accidents and incidents, accidents and incidents. Although Smartwings QS-1125 flight of 22 August 2019 successfully made an emergency landing at destination, the captain was censured for failing to follow mandatory procedures, including for not landing at the nearest possible diversion airport after an engine failure.


Human factors of third parties

Unsafe human factors are not limited to pilot errors. Third party factors include ground crew mishaps, ground vehicle to aircraft collisions and engineering maintenance related problems. For example, failure to properly close a cargo door on Turkish Airlines Flight 981 in 1974 caused the loss of the aircraft. (However, design of the cargo door latch was also a major factor in the accident.) In the case of
Japan Airlines Flight 123 Japan Air Lines Flight 123 (JAL123) () was a scheduled domestic Japan Air Lines passenger flight from Haneda Airport in Tokyo to Itami International Airport in Osaka. On August 12, 1985, the Boeing 747SR operating this flight suffered a sudden ...
in 1985, improper repair of previous damage led to explosive decompression of the cabin, which in turn destroyed the vertical stabilizer and damaged all four hydraulic systems which powered all the flight controls.


Controlled flight into terrain

''Controlled flight into terrain'' (CFIT) is a class of accidents in which an aircraft is flown under control into terrain or man-made structures. CFIT accidents typically result from pilot error or of navigational system error. Failure to protect ILS critical areas can also cause CFIT accidents. In December 1995, American Airlines Flight 965 tracked off course while approaching Cali, Colombia, and hit a mountainside despite a terrain awareness and warning system (TAWS) terrain warning in the cockpit and desperate pilot attempt to gain altitude after the warning. Crew position awareness and monitoring of navigational systems are essential to the prevention of CFIT accidents. , over 40,000 aircraft had enhanced TAWS installed, and they had flown over 800 million hours without a CFIT accident. Another anti-CFIT tool is the Minimum Safe Altitude Warning (MSAW) system which monitors the altitudes transmitted by aircraft transponders and compares that with the system's defined minimum safe altitudes for a given area. When the system determines the aircraft is lower, or might soon be lower, than the minimum safe altitude, the
air traffic control Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled airs ...
ler receives an acoustic and visual warning and then alerts the pilot that the aircraft is too low.


Electromagnetic interference

The use of certain electronic equipment is partially or entirely prohibited as it might interfere with aircraft operation, such as causing
compass A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself wit ...
deviations. Use of some types of personal electronic devices is prohibited when an aircraft is below , taking off, or landing. Use of a mobile phone is prohibited on most flights because in-flight usage creates problems with ground-based cells.


Ground damage

Various ground support equipment operate in close proximity to the fuselage and wings to service the aircraft and occasionally cause accidental damage in the form of scratches in the paint or small dents in the skin. However, because aircraft structures (including the outer skin) play such a critical role in the safe operation of a flight, all damage is inspected, measured, and possibly tested to ensure that any damage is within safe tolerances. An example problem was the depressurization incident on Alaska Airlines Flight 536 in 2005. During ground services a baggage handler hit the side of the aircraft with a tug towing a train of baggage carts. This damaged the metal skin of the aircraft. This damage was not reported and the plane departed. Climbing through the damaged section of the skin gave way under the difference in pressure between the inside of the aircraft and the outside air. The cabin depressurized explosively necessitating a rapid descent to denser (breathable) air and an emergency landing. Post-landing examination of the fuselage revealed a hole on the right side of the airplane.


Volcanic ash

Plumes of volcanic ash near active volcanoes can damage Propeller (aircraft), propellers,
engines An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power g ...
and cockpit windows. In 1982, British Airways Flight 9 flew through an ash cloud and temporarily lost power from all four engines. The plane was badly damaged, with all the leading edges being scratched. The front windscreens had been so badly "sand" blasted by the ash that they could not be used to land the aircraft. Prior to 2010 the general approach taken by airspace regulators was that if the ash concentration rose above zero, then the airspace was considered unsafe and was consequently closed. Volcanic Ash Advisory Centers enable liaison between meteorologists, volcanologists, and the aviation industry.


Runway safety

Types of runway safety incidents include: * Runway excursion – an incident involving only a single aircraft making an inappropriate exit from the runway. * Runway overrun – a specific type of excursion where the aircraft does not stop before the end of the runway (e.g., Air France Flight 358). * Runway incursion – incorrect presence of a vehicle, person, or another aircraft on the runway (e.g., Tenerife airport disaster). * Runway confusion – crew misidentification the runway for landing or take-off (e.g., Comair Flight 191, Singapore Airlines Flight 6).


Terrorism

Aircrew are normally trained to handle Aircraft hijacking, hijack situations. Since the September 11, 2001, attacks, stricter airport security, airport and airline security measures are in place to prevent terrorism, such as security checkpoints and locking the cockpit doors during flight. In the United States, the Federal Flight Deck Officer program is run by the Federal Air Marshal Service, with the aim of training active and licensed airline pilots to carry weapons and defend their aircraft against criminal activity and terrorism. Upon completion of government training, selected pilots enter a covert law enforcement and counter-terrorism service. Their jurisdiction is normally limited to a flight deck or a cabin of a commercial airliner or a cargo aircraft they operate while on duty.


Military action

Passenger planes have rarely been attacked in both peacetime and war. Examples: * In 1955, Bulgaria shot down El Al Flight 402. * In 1973, Israel shot down Libyan Arab Airlines Flight 114. * In 1983, the Soviet Union shot down Korean Air Lines Flight 007. * In 1988, the United States shot down Iran Air Flight 655. * In 2001, the Ukrainian Air Force accidentally shot down Siberia Airlines Flight 1812 during an exercise. * In 2014, a rebel from Ukraine- armed with the Russian Aerospace Defense Forces Buk missile system - shot down Malaysia Airlines Flight 17. * In 2020, Iran shot down Ukraine International Airlines Flight 752.


Accident survivability

Earlier tragedies investigations and improved engineering has allowed many safety improvements that have allowed an increasing safer aviation.


Airport design

Airport design and location can have a large impact on aviation safety, especially since some airports such as Chicago Midway International Airport were originally built for propeller planes and many airports are in congested areas where it is difficult to meet newer safety standards. For instance, the FAA issued rules in 1999 calling for a runway safety area, usually extending to each side and beyond the end of a runway. This is intended to cover ninety percent of the cases of an aircraft leaving the runway by providing a buffer space free of obstacles. Many older airports do not meet this standard. One method of substituting for the at the end of a runway for airports in congested areas is to install an engineered materials arrestor system (EMAS). These systems are usually made of a lightweight, crushable concrete that absorbs the energy of the aircraft to bring it to a rapid stop. , they have stopped three aircraft at John F. Kennedy International Airport, JFK Airport.


Emergency airplane evacuations

According to a 2000 report by the National Transportation Safety Board, emergency aircraft evacuations happen about once every 11 days in the U.S. While some situations are extremely dire, such as when the plane is on fire, in many cases the greatest challenge for passengers can be the use of the evacuation slide. In a ''Time'' article on the subject, Amanda Ripley reported that when a new supersized Airbus A380 underwent mandatory evacuation tests in 2006, thirty-three of the 873 evacuating volunteers got hurt. While the evacuation was considered a success, one volunteer suffered a broken leg, while the remaining 32 received slide burns. Such accidents are common. In her article, Ripley provided tips on how to make it down the airplane slide without injury. Another improvement to airplane evacuations is the requirement by the Federal Aviation Administration for planes to demonstrate an evacuation time of 90 seconds with half the emergency exits blocked for each type of airplane in their fleet. According to studies, 90 seconds is the time needed to evacuate before the plane starts burning, before there can be a very large fire or explosions, or before fumes fill the cabin.


Aircraft materials and design

Changes such as using new materials for seat fabric and insulation has given between 40 and 60 additional seconds to people on board to evacuate before the cabin gets filled with fire and potential deadly fumes. Other improvements through the years include the use of properly rated seatbelts, impact resistant seat frames, and airplane wings and engines designed to shear off to absorb impact forces.


Radar and wind shear detection systems

As the result of the accidents due to wind shear and other weather disturbances, most notably the 1985 crash of Delta Air Lines Flight 191, the U.S. Federal Aviation Administration mandated that all commercial aircraft have Airborne wind shear detection and alert system, on-board wind shear detection systems by 1993. Since 1995, the number of major civil aircraft accidents caused by wind shear has dropped to approximately one every ten years, due to the mandated on-board detection as well as the addition of Doppler
weather radar Weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.). Modern weather radars are mostly pulse- ...
units on the ground (NEXRAD). The installation of high-resolution Terminal Doppler Weather Radar stations at many U.S. airports that are commonly affected by wind shear has further aided the ability of pilots and ground controllers to avoid wind shear conditions.


Accidents and incidents

* List of airship accidents * :Lists of aviation accidents and incidents, Lists of aviation accidents and incidents * Aviation accidents and incidents * List of airliner shootdown incidents * Flight recorder, includes ''flight data recorder'' and ''cockpit voice recorder''


National investigation organizations

* Australian Transport Safety Bureau
Flugunfalluntersuchungsstelle im BMVIT
(Austria)
Centro de Investigação e Prevenção de Acidentes Aeronáuticos
(Brazil) * Transportation Safety Board of Canada * Air Accidents Investigation Institute (Czech Republic)
Danish Aircraft Accident Investigation Board
* Bureau d'Enquêtes et d'Analyses pour la sécurité de l'Aviation Civile (France) * Bundesstelle für Flugunfalluntersuchung (Germany) * Air Accident Investigation Unit (Ireland) * ANSV, Agenzia Nazionale per la Sicurezza del Volo (Italy) * Aircraft and Railway Accidents Investigation Commission (Japan) * Civil Aviation Authority of New Zealand * Transport Accident Investigation Commission (New Zealand) * Onderzoeksraad voor Veiligheid (The Netherlands) * Civil Aviation Authority of the Philippines * Comisión de Investigación de Accidentes e Incidentes de Aviación Civil (Spain) * Swedish Accident Investigation Board * Aircraft Accident Investigation Bureau (Switzerland), Aircraft Accident Investigation Bureau (Switzerland) * Air Accidents Investigation Branch (UK) * National Transportation Safety Board (USA)
European Co-ordination Center for Aircraft Incident Reporting Systems
(ECCAIRS) *
International Civil Aviation Organization The International Civil Aviation Organization (ICAO, ) is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international a ...
* South African Civil Aviation Authority (South Africa)
Aircraft Accident Investigation Bureau
(India)
KNKT - Komite Nasional Keselamatan Transportasi
(Indonesia)


Air safety investigators

Air safety investigators are trained and authorized to investigate aviation accidents and incidents: to research, analyse, and report their conclusions. They may be specialized in flight operations, training, aircraft structures, air traffic control, flight recorders or human factors. They are employed by government organizations responsible for aviation safety, manufacturers or unions, though only government organizations have statutory powers to investigate.


Safety improvement initiatives

The safety improvement initiatives are aviation safety partnerships between regulators, manufacturers, operators, professional unions, research organisations, and international aviation organisations to further enhance safety. Some major safety initiatives worldwide are:
Commercial Aviation Safety Team (CAST)
in the US. The Commercial Aviation Safety Team (CAST) was founded in 1998 with a goal to reduce the commercial aviation fatality rate in the United States by 80 percent by 2007.
European Strategic Safety Initiative (ESSI)
The European Strategic Safety Initiative (ESSI) is an aviation safety partnership between EASA, other regulators and the industry. The initiative objective is to further enhance safety for citizens in Europe and worldwide through safety analysis, implementation of cost effective action plans, and coordination with other safety initiatives worldwide. After the disappearance of Malaysia Airlines Flight 370, in June 2014, the International Air Transport Association said it was working on implementing new measures to track aircraft in flight in real time. A special panel was considering a range of options including the production of equipment especially designed to ensure real-time tracking. Since pilot error accounts for between one-third and 60% of aviation accidents, advances in automation and technology could replace some or all of the duties of the aircraft pilots. Automation since the 1980s has already eliminated the need for flight engineers. In complex situations with severely degraded systems, the problem-solving and judgement capability of humans is challenging to achieve with automated systems, for example the catastrophic engine failures experienced by
United Airlines Flight 232 United Airlines Flight 232 was a regularly scheduled United Airlines flight from Stapleton International Airport in Denver to O'Hare International Airport in Chicago, continuing to Philadelphia International Airport. On July 19, 1989, the DC ...
and
Qantas Flight 32 Qantas Flight 32 was a regularly scheduled passenger flight from London to Sydney via Singapore. On 4 November 2010, the aircraft operating the route, an Airbus A380, suffered an uncontained failure in one of its four Rolls-Royce Trent 900 eng ...
. However, with more accurate software modeling of aeronautic factors, test planes have been McDonnell Douglas F-15 STOL/MTD, successfully flown in these conditions. While the Aviation accidents and incidents, accident rate is very low, to ensure they do not rise with the air transport growth, experts recommend creating a robust culture of collecting information from employees without blame.


Regulation

*Directorate- General of Civil Aviation, India. * Civil Aviation Authority (United Kingdom), Civil Aviation Authority (United Kingdom) * Department of Infrastructure, Transport, Regional Development and Local Government (Australia) * European Aviation Safety Agency * Federal Aviation Administration (United States) ** Federal Aviation Regulations * Irish Aviation Authority * Transport Canada * Directorate General of Civil Aviation (Indonesia), Directorate General of Civil Aviation (Indonesia)


See also

* Aircraft fire trainer * Aircraft hijacking * Airport security * Aviation Safety Network * Aviation Safety Reporting System * Ballistic parachute * Crashworthiness * Chicago Convention on International Civil Aviation * Hazard analysis * Health hazards of air travel * IATA Operational Safety Audit * JACDEC, Jet Airliner Crash Data Evaluation Centre * Lasers and aviation safety * Mid-air collision * Pilot error * Safety of emergency medical services flights * Sensory illusions in aviation * Sixty second review, a technique used by flight attendants to focus and prepare for a sudden emergency * SKYbrary * Swiss cheese model * System accident * Tombstone mentality * * Uncontrolled decompression * Wind shear * Zonal safety analysis


Notes


References


External links


10 Plane Crashes That Changed Aviation
*
Safety Behaviours, a guide for pilots (comprehensive human factors information)

NASA Aviation Safety Reporting System (ASRS)

Latest Aviation Safety Occurrences at the Aviation Safety Network

Aviation Safety: Advancements Being Pursued to Improve Airliner Cabin Occupant Safety and Health, 2003
{{DEFAULTSORT:Aviation Safety Aviation safety, Aircraft maintenance, Safety