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{{Refimprove|date=July 2008}}
[[Image:Controlled impact demonstration dummies.jpg|thumb|right|NASA air safety experiment ([[Controlled Impact Demonstration|CID project]])]]

'''Air safety''' is a term encompassing the theory, investigation and categorization of [[Aviation accidents and incidents|flight failures]], and the prevention of such failures through regulation, education and training. It can also be applied in the context of campaigns that inform the public as to the safety of [[air travel]].

==Institutions==
===United States===
During the 1920s, the first laws were passed in the USA to regulate [[civil aviation]]. Of particular significance was the [[United States government role in civil aviation|Air Commerce Act 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|Department of Commerce]].

Despite this, 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 {{convert|1000000|mi|km}} flown. Based on the current numbers flying, this would equate to 7,000 fatal incidents per year.

The fatal incident rate has declined steadily ever since, and, 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 {{convert|1000|mi|km}} counts as 100,000 person-miles, making it comparable with methods of transportation with different numbers of passengers, such as one person driving a [[Automobile|car]] for {{convert|100000|mi|km}}, which is also 100,000 person-miles), making it one of the safest modes of transportation, as measured by distance traveled.

A disproportionate number of all U.S. aircraft crashes occur in Alaska, largely as a result of severe weather conditions. Between 1990-2006 there were 1441 commuter and air taxi crashes in the U.S. of which 373 (26%) were fatal, resulting in 1063 deaths (142 occupational pilot deaths). Alaska accounted for 513 (36%) of the total U.S. crashes.<ref>{{cite web|url= http://www.cdc.gov/niosh/topics/aviation/ |title=NIOSH Commercial Aviation in Alaska |accessdate=2007-10-15|publisher=United States National Institute for Occupational Safety and Health}}</ref>

Another aspect of safety is protection from attack currently known as ''Security'' (as the ISO definition of safety encompasses non-intentional (safety_safety) and intentional (safety_security) causes of damage). The [[September 11, 2001 attacks|terrorist attacks]] of 2001 are not counted as accidents. However, even if they were counted as accidents they would have added only about 2 deaths per 2,000,000,000 person-miles. Only 2 months later, [[American Airlines Flight 587]] crashed in [[Queens]], [[New York City|NY]], killing 256 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 1,000,000,000 person-miles), is safe compared to some other forms of transport, if measured by distance traveled.  

Safety improvements have resulted from improved [[Aeronautics|aircraft design]], engineering and maintenance, the evolution of navigation aids, and safety protocols and procedures.

It is often reported that air travel is the safest in terms of deaths per passenger mile. The [[National Transportation Safety Board]] (2006) reports 1.3 deaths per hundred million vehicle miles for travel by car, and 1.7 deaths per hundred million vehicle miles for travel by air.  These are not passenger miles. If an airplane has 100 passengers, then the passenger miles are 100 times higher, making the risk 100 times lower. The number of deaths per passenger mile on commercial airlines between 1995 and 2000 is about 3 deaths per 10 billion passenger miles.<ref>[http://www.iii.org/media/facts/statsbyissue/aviation/?table_sort_735941=9 Aircraft Accidents in the United States, 2006]</ref>

==Navigation aids and instrument flight==
One of the first [[Air navigation#Navigation aids|navigation aids]] to be introduced (in the USA in the late 1920s) was airfield lighting to assist pilots to make landings in poor weather or after dark. The [[Precision Approach Path Indicator]] 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).

In 1929 [[Jimmy Doolittle#Instrument flight|Jimmy Doolittle]] developed [[Flight instruments|instrument flight]].

With the spread of [[radio]] technology, several experimental [[Radio navigation|radio based navigation aids]] were developed from the late 1920s onwards. These were most successfully used in conjunction with [[flight instruments|instruments]] in the [[cockpit]] in the form of [[Instrument landing system]]s (ILS), first used by a scheduled flight to make a landing in a [[Winter storm#Snowstorm|snowstorm]] at [[Pittsburgh, Pennsylvania|Pittsburgh]] in 1938. A form of ILS was adopted by the ICAO for international use in 1949.

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, joined in 1948 by [[distance measuring equipment]] (DME), and in the 1950s by [[airport surveillance radar]] as an aid to [[air traffic control]]. [[VHF omnidirectional range]] (VOR) stations became the predominate means of route navigation during the 1960s, superseding the low frequency radio ranges and the [[Non-directional beacon]] (NDB). The ground based VOR stations were often co-located with DME transmitters and then labeled as VOR-DME stations on navigation charts. VORTAC stations, which combined VOR and TACAN features (military  TACtical Air Navigation) — the latter including both a DME distance feature and a separate TACAN azimuth feature, which provides military pilots data similar to the civilian VOR, were also used in that new system. With the proper receiving equipment in the aircraft, pilots could know their radials in degrees to/from the VOR station, as well as the slant range distance to/from, if the station was co-located with DME or TACAN.<ref>[http://www.campbells.org/Airplanes/VOR/vor.html The VOR]</ref>

All of the ground-based navigation aids are being supplemented by [[satellite]]-based aids like [[Global Positioning System]] (GPS), which make it possible for [[Aircrew member|aircrews]] to know their position with great precision anywhere in the world. With the arrival of [[Wide Area Augmentation System]] (WAAS), GPS navigation has become accurate enough for vertical (altitude) as well as horizontal use, and is being used increasingly for 
instrument approaches as well as en-route navigation. However, since the GPS constellation is a [[single point of failure]] that can be switched off by the [[Military of the United States|U.S. military]] in time of crisis, onboard [[Inertial Navigation System]] (INS) or ground-based navigation aids are still required for backup.

==Air safety topics==
=== Misinformation and lack of information ===
[[Image:PrintingError.jpg ‎|thumb|400px|[[Herzliya Airport]] (Israel) [[Runway]] location and [[airfield traffic pattern]] chart (left) was erroneously printed as a result of "black layer" 180° misplacement. The corrected chart is on the right.]]
A pilot might fly the plane in an accident-prone manner when misinformed by a printed document (manual, map etc.), by reacting to a faulty instrument or indicator (either in cockpit or on ground)<ref>[http://www.haaretz.com/news/two-planes-nearly-crash-at-ben-gurion-airport-due-to-glitch-1.278096 Haaretz.com]: Two planes nearly crash at Ben Gurion Airport due to glitch</ref><ref>[http://new.jpost.com/Israel/Article.aspx?id=160314 Jerusalem Post]: Weeds blamed for spate of near-misses at Ben-Gurion Airport</ref> or by following inaccurate instructions or information from flight or ground control.<ref>[http://momento24.com/en/2010/01/21/ezeiza-an-error-in-the-control-tower-almost-caused-two-planes-to-collide/ momento24.com]: An error in the control tower almost caused two planes to collide</ref><ref>[http://abclocal.go.com/kgo/story?section=news/local/peninsula&id=7359230 ABC local]: NTSB, FAA investigate near-miss mid-air collision</ref><ref>[http://www.nytimes.com/2007/07/20/nyregion/20laguardia.html?_r=1 New York Times]: La Guardia Near-Crash Is One of a Rising Number</ref> Lack of information by the control tower, or delayed instructions, are major factors contributing to accidents.<ref>[http://www.bfu-web.de/cln_016/nn_226462/EN/Publications/Investigation_20Report/2002/Report__02__AX001-1-2___C3_9Cberlingen__Report,templateId=raw,property=publicationFile.pdf/Report_02_AX001-1-2_Überlingen_Report.pdf BFU-WEB.de]: Investigation Report on crash near Ueberlingen</ref>

===Lightning===
Boeing studies have shown that airliners are struck by [[lightning]] on average of twice per year. While the "flash and bang" is startling to the passengers and crew, aircraft are able to withstand normal lightning strikes.

The dangers of more powerful [[Lightning#Positive lightning|positive lightning]] were not understood until the destruction of a [[Glider (sailplane)|glider]] in 1999.<ref name=schleicher>[http://www.aaib.gov.uk/publications/bulletins/december_1999/schleicher_500699.cfm Schleicher ASK 21 two seat glider]</ref> It has since been suggested that positive lightning may have caused the crash of [[Pan American World Airways|Pan Am]] [[Pan Am Flight 214|Flight 214]] in 1963. At that time aircraft were not designed to withstand such strikes, since their existence was unknown at the time standards were set. The 1985 standard in force at the time of the glider crash, Advisory Circular AC 20-53A,<ref name=schleicher /> was replaced by Advisory Circular AC 20-53B in 2006,<ref>[http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/MainFrame?OpenFrameSet&CFID=11301165& FAA Advisory Circulars]</ref> however it is unclear whether adequate protection against positive lighting was incorporated.<ref>[http://www.nolan-law.com/hiding-requirements-suspicion-theyre-inadequate/ Hiding requirements = suspicion they're inadequate], Nolan Law Group, January 18, 2010</ref><ref>[http://www.lightningtech.com/pdfs/A_PROPOSED_ADDITION_TO_LIGHTNING_ENVIRONMENT_STDS.pdf A Proposed Addition to the Lightning Environment Standards Applicable to Aircraft], J. Anderson Plumer
Lightning Technologies, Inc, published 2005-09-27</ref>

The effects of normal lightning on traditional metal-covered aircraft are well understood and serious damage from a lightning strike on an airplane is rare. However, as more and more aircraft, like the upcoming [[Boeing 787]], whose whole exterior is made of non-conducting [[composite material]]s take to the skies, additional design effort and testing must be made before certification authorities will permit these aircraft in commercial service.

===Ice and snow===
[[Snow]]y and icy conditions are frequent contributors to airline accidents. The December 8, 2005 accident where [[Southwest Airlines Flight 1248]] slid off the end of the [[runway]] in heavy snow conditions is just one of many examples. Just as on a [[road]], [[ice]] and snow buildup can make braking and steering difficult or impossible.

The [[Atmospheric icing|icing]] of wings is another problem and measures have been developed to combat it. Even a small amount of ice or coarse [[frost]] can greatly decrease the ability of a wing to develop [[Lift (force)|lift]]. This could prevent an  aircraft from taking off. If ice builds up during flight the result can be catastrophic as evidenced by the crash of [[American Eagle Airlines|American Eagle]] [[American Eagle Flight 4184|Flight 4184]] (an [[ATR 72]] aircraft) near [[Roselawn, Indiana]] on October 31, 1994, killing 68, or [[Air Florida Flight 90]].<ref>[http://www.airlinesafety.com/letters/atr.htm/ airlinesafety.com - Letters to the Editor]</ref>

Airlines and airports ensure that aircraft are properly [[Deicing|de-iced]] before [[takeoff]] whenever the weather threatens to create [[icing conditions]]. Modern airliners are designed to prevent ice buildup on [[wing]]s, [[Aircraft engine|engines]], and tails ([[empennage]]) by either routing heated air from [[jet engine]]s through the [[leading edge]]s of the wing, tail, and inlets, or on slower aircraft, by use of inflatable rubber "[[Deicing boot|boots]]" that expand and break off any accumulated ice.

Finally, [[Flight dispatcher|airline dispatch offices]] keep watch on weather along the routes of their flights, helping the [[Aviator|pilots]] avoid the worst of inflight icing conditions. Pilots can also be equipped with an [[ice detector]] in order to leave icy areas they have flown into.

===Engine failure===
Although aircraft are now designed to fly even after the [[flameout|failure]] of one or more aircraft engines, the failure of the second [[engine]] on one side for example is obviously serious. Losing all engine power is even more serious, as illustrated by the 1970 [[Dominicana DC-9 air disaster]], when [[fuel]] contamination caused the failure of both engines. To have an [[emergency landing]] site is then very important. 

In the 1983 ''[[Gimli Glider]]'' incident, an [[Air Canada]] flight suffered fuel exhaustion during [[Cruise (flight)|cruise flight]], forcing the pilot to glide the plane to an emergency [[deadstick landing]]. The automatic deployment of the [[ram air turbine]] maintained the necessary [[Hydraulics|hydraulic pressure]] to the flight controls, so that the pilot was able to land with only a minimal amount of damage to the plane, and minor (evacuation) injuries to a few passengers.

The ultimate form of [[Turbine engine failure|engine failure]], physical separation, occurred in 1979 when a complete engine detached from [[American Airlines Flight 191]], causing damage to the aircraft and [[loss of control]].

===Metal fatigue===
[[Fatigue (material)|Metal fatigue]] has caused failure either of the engine or of the aircraft body.

Examples:

* the January 8, 1989 [[Kegworth air disaster]]
* [[De Havilland Comet]]s incidents in 1953 and 1954
* [[Aloha Airlines]] [[Aloha Airlines Flight 243|Flight 243]] in 1988

Now that the subject is better understood, rigorous inspection and [[nondestructive testing]] procedures are in place.

===Delamination===
[[Composite material]]s consist of layers of [[fiber]]s embedded in a [[resin]] matrix. In some cases, especially when subjected to [[cyclic stress]], the fibers may tear off the matrix, the layers of the material then separate from each other - a process called [[delamination]], and form a [[mica]]-like structure which then falls apart. As the failure develops inside the material, nothing is shown on the surface; instrument methods (often [[ultrasound]]-based) have to be used to detect such a material failure.

Aircraft have developed delamination problems, but most were discovered before they caused a catastrophic failure. Delamination risk is as old as composite material. Even in the 1940s, several [[Yakovlev Yak-9]]s experienced delamination of [[plywood]] in their construction.

===Stalling===
[[Stall (flight)|Stall]]ing an aircraft (increasing the [[angle of attack]] to a point at which the wings fail to produce enough [[Lift (force)|lift]]), is very dangerous and usually results in a crash unless the pilot quickly reacts in the proper manner and there is sufficient altitude left to regain adequate flying airspeed, while the plane is losing altitude. Devices have been developed to warn the pilot when the plane's speed is coming close to the stall speed. These include stall warning horns (now standard on virtually all powered aircraft), [[stick shaker]]s and voice warnings. Most stalls are a result of the pilot allowing the plane's to go too slow for the particular weight and configuration at the time.  There is, however, such a thing as a high-speed stall.  That can occur when a plane pulls out of a high speed dive too rapidly, causing the angle of attack of the airfoil to become so extreme that the air flow over the top of the wing is broken up into a turbulent mass, which destroys the lift capability of the wings.

'''Notable crashes, caused by a full stall of the airfoils:'''

* [[British European Airways Flight 548]], June 18, 1972
* [[United Airlines Flight 553]], December 8, 1972
* [[Aeroflot Flight 7425]], July 10, 1985
* [[Arrow Air Flight 1285]], December 12, 1985
* [[Northwest Airlines Flight 255]], August 16, 1987
* [[Delta Air Lines Flight 1141]], August 31, 1988
* The [[Paul Wellstone]] King Air Charter crash, October 25, 2002
* [[Colgan Air Flight 3407]], February 12, 2009
* [[Turkish Airlines Flight 1951]], February 25, 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 [[Inflammability|flammability]] and the [[toxicity]] of [[smoke]]. When the tests fail, they fail on a prototype in an engineering laboratory, rather than in an aircraft.

Fire on board the aircraft, and more especially the toxic smoke generated, 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. Two years later 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 1985 [[British Airtours]] [[British Airtours Flight 28M|Flight 28M]]. That accident raised serious concerns relating to survivability, something that prior to 1985 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. A large amount of research into evacuation and cabin and seating layouts was carried at [[Cranfield Institute]] to try to measure what makes a good evacuation route, which led to the seat layout by [[Overwing exits]] being changed by mandate and the examination of evacuation requirements relating to the design of galley areas. The use of [[smoke hood]]s or misting systems were also examined although both were rejected.

The cargo holds of most airliners are equipped with "fire bottles" (essentially remote-controlled [[fire extinguisher]]s) to combat a fire that might occur in the baggage holds, below the passenger cabin. In May 1996 [[ValuJet Airlines]] [[ValuJet Flight 592|Flight 592]] crashed into the [[Florida]] [[Everglades]] a few minutes after takeoff after a fire broke out in the forward cargo hold. All 110 aboard were killed. 

At one time [[fire fighting]] [[foam path]]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.

===Bird strike===
[[Bird strike]] is an aviation term for a collision between a bird and an aircraft. It is a common threat to aircraft safety and has caused a number of fatal accidents. In 1988 an [[Ethiopian Airlines]] [[Boeing 737]] sucked [[Columbidae|pigeons]] into both engines during take-off and then crashed in an attempt to return to the [[Bahir Dar]] airport; of the 104 people aboard, 35 died and 21 were injured. In another incident in 1995, a [[Dassault Falcon|Dassault Falcon 20]] crashed at a [[Paris]] airport during an emergency landing attempt after sucking [[lapwing]]s into an engine, which caused an engine failure and a fire in the airplane [[fuselage]]; all 10 people on board were killed.<ref>[http://www.tc.gc.ca/civilaviation/AerodromeAirNav/Standards/WildlifeControl/tp13549/Chapter1.htm Transport Canada - Sharing the Skies]</ref>  [[Canada Geese]] were ingested into the engines of [[US Airways 1549]] causing the engines to fail on the [[Airbus A320]] that crash landed onto the [[Hudson River]].

Modern jet engines have the capability of surviving an ingestion of a bird. Small fast planes, such as military [[Fighter aircraft|jet fighters]], are at higher risk than heavy multi-engine ones. This is due to the fact that the fan of a high-bypass [[turbofan]] engine, typical on transport aircraft, acts as a centrifugal separator to force ingested materials (birds, ice, etc.) to the outside of the fan's disc. As a result, such materials go through the relatively unobstructed [[bypass duct]], rather than through the core of the engine, which contains the smaller and more delicate compressor blades. [[Military aircraft]] designed for high-speed flight typically have pure [[turbojet]], or low-bypass turbofan engines, increasing the risk that ingested materials will get into the core of the engine to cause damage.

The highest risk of the bird strike is during the takeoff and [[landing]], in low [[altitude]]s, which is in the vicinity of the [[airport]]s. Some airports use active countermeasures, ranging from a person with a [[shotgun]] through recorded sounds of predators to employing [[Falconry|falconer]]s. Poisonous grass can be planted that is not palatable to birds, nor to insects that attract [[Insectivore|insectivorous]] birds. Passive countermeasures involve sensible land-use management, avoiding conditions attracting flocks of birds to the area (e.g. [[landfill]]s). Another tactic found effective is to let the grass at the airfield grow taller (approximately {{in to cm|num=12|abbr=no|spell=Commonwealth|precision=0|wiki=yes}}) as some species of birds won't land if they cannot see one another.

Bird strike can also break windshields and wound the pilot.

===Ground damage===
Aircraft are occasionally damaged by [[Ground Support Equipment|ground equipment]] at the airport. In the act of servicing the aircraft between flights a great deal of ground equipment must operate in close proximity to the fuselage and wings. Occasionally the aircraft gets bumped or worse.

Damage may be in the form of simple 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. A dent that may look no worse than common "parking lot damage" to an automobile can be serious enough to ground an airplane until a repair can be made.

An example of the seriousness of this problem was the December 26, 2005 depressurization incident on [[Alaska Airlines]] flight 536. During ground services a [[baggage handler]] hit the side of the aircraft with a tug towing a train of [[baggage cart]]s. This damaged the metal skin of the aircraft. This damage was not reported and the plane departed. Climbing through {{ft to m|num=26000|abbr=no|spell=Commonwealth|sigfig=2|wiki=yes}} the damaged section of the skin gave way due to the growing difference in pressure between the inside of the aircraft and the outside air. The [[Cabin pressurization|cabin depressurized]] with a bang, frightening all aboard and necessitating a rapid descent back to denser (breathable) air and an emergency landing. Post landing examination of the fuselage revealed a {{in to cm|12|6|abbr=yes}} hole between the middle and forward cargo doors on the right side of the airplane.<ref>{{Cite document | title = National Transportation Safety Board -- Aviation Accidents: SEA06LA033 | date = 2006-08-29 | url = http://www.ntsb.gov/ntsb/brief.asp?ev_id=20051229X02026&key=1 | accessdate = 2007-07-14 | publisher = [[National Transportation Safety Board]] | postscript = <!--None-->}}</ref>

The three pieces of ground equipment that most frequently damage aircraft are the [[Jet bridge|passenger boarding bridge]], catering trucks, and cargo "[[Ground Support Equipment#Mobile belt-loaders|beltloaders]]." However, any other equipment found on an [[airport ramp]] can damage an aircraft through careless use, high winds, mechanical failure, and so on.

The generic industry [[Colloquialism|colloquial]] term for this damage is "ramp rash", or "[[hangar]] rash".

===Volcanic ash===
Plumes of [[volcanic ash]] near active [[volcano]]es present a risk especially for night flights. The ash is hard and abrasive and can quickly cause significant wear on the [[propeller]]s and [[jet engine#Major components|turbocompressor blades]], and scratch the cockpit windows, impairing visibility. It contaminates fuel and water systems, can jam gears, and can cause a flameout of the [[jet engine|engines]]. Its particles have low [[melting point]], so they melt in the [[combustion chamber]] and the [[ceramic]] mass then sticks on the turbine blades, fuel nozzles, and the [[combustor]]s, which can lead to a total engine failure. It can get inside the cabin and contaminate everything there, and can damage the airplane electronics.<ref>[http://volcanoes.usgs.gov/Hazards/Effects/Ash+Aircraft.html Danger to Aircraft from Volcanic Eruption Clouds]</ref>
<ref>[http://www.skybrary.aero/index.php/Volcanic_Ash Guidance for Flight Crews and Controllers]</ref>

There are many instances of damage to jet aircraft from ash encounters. In one of them in 1982, [[British Airways Flight 9]] flew through an ash cloud, lost all four engines, and descended from {{ft to m|36000|abbr=yes}} to only {{ft to m|12000|abbr=yes}} before the flight crew managed to restart the engines. A similar incident occurred on December 15, 1989 involving [[KLM Flight 867]].

With the growing density of air traffic, encounters like this are becoming more common. In 1991 the aviation industry decided to set up [[Volcanic Ash Advisory Center]]s (VAACs), one for each of 9 regions of the world, acting as liaisons between [[Meteorology|meteorologist]]s, [[Volcanology|volcanologist]]s, and the aviation industry.<ref>[http://pubs.usgs.gov/fs/fs030-97/ Volcanic Ash–Danger to Aircraft in the North Pacific]</ref>

Prior to the European [[Air travel disruption after the 2010 Eyjafjallajökull eruption|air travel disruption]] of April 2010, aircraft engine manufacturers had not defined specific particle levels above which engines were considered to be at risk.  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.<ref>http://www.newscientist.com/article/dn18797-can-we-fly-safely-through-volcanic-ash.html</ref>

The April 2010 [[2010 eruptions of Eyjafjallajökull|eruptions]] of [[Eyjafjallajökull]] caused sufficient economic difficulties that aircraft manufacturers were forced to define specific limits on how much ash is considered acceptable for a jet engine to ingest without damage.  In April, the [[Civil Aviation Authority (United Kingdom)|CAA]], in conjunction with engine manufacturers, set the safe upper limit of ash density to be 2&nbsp;mg per cubic metre of air space.<ref>http://www.newscientist.com/article/dn18802-engine-stripdowns-establish-safe-volcanic-ash-levels.html</ref>

From noon 18 May 2010, the CAA revised the safe limit upwards to 4&nbsp;mg per cubic metre of air space.<ref>http://news.bbc.co.uk/1/hi/uk/8685913.stm</ref>

In order to minimise the level of further disruption that this and other volcanic eruptions could cause, the CAA announced the creation of a new category of restricted airspace called a [[Time Limited Zone]].<ref>http://www.caa.co.uk/docs/7/Letter%20to%20NSAs%20re%20Volcanic%20Ash-%20Creation%20of%20TLZ.pdf</ref>  Airspace categorised as TLZ is similar to airspace experiencing severe weather conditions in that the restrictions are expected to be of a short duration; however, the key difference with TLZ airspace is that airlines must produce certificates of compliance in order for their aircraft to enter these areas.  [[Flybe]] was the first airline to conform to these regulations and their aircraft will be permitted to enter airspace in which the ash density is between 2&nbsp;mg and 4&nbsp;mg per cubic metre.<ref>http://news.sky.com/skynews/Home/UK-News/Volcano-Ash-New-Time-Limited-Zone-Introduced-To-Reduce-Flight-Restrictions-Due-To-Ash-Cloud/Article/201005315633952?f=rss</ref>

Any airspace in which the ash density exceeds 4&nbsp;mg per cubic metre is categorised as a [[no fly zone]].

====Aviation risks of flight through downstream ash clouds====
It is important to make a distinction between flight through (or in immediate vicinity of) the eruption plume and flight through so-called affected airspace<ref>[http://www.skybrary.aero/index.php/Managing_the_Risk_to_the_Safety_of_Aircraft_in_Flight_Caused_by_Volcanic_Ash "Managing the Risk to the Safety of Aircraft in Flight Caused by Volcanic Ash"]</ref>. Volcanic ash in the immediate vicinity of the eruption plume is of an entirely different particle size range and density to that found in downwind dispersal clouds which contain only the finest grade of ash. The ash loading at which this process affects normal engine operation is not established beyond the awareness that relatively high ash densities must exist. Whether this silica-melt risk remains at the much lower ash densities characteristic of downstream ash clouds is currently unclear. This is therefore a serious safety hazard which invites preventive risk management strategies in line with other comparable aviation risks.
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===Human factors===
{{See also|aviation medicine}}
[[Image:CID slapdown.jpg|thumb|right|NASA air safety experiment. The airplane is a Boeing 720 testing a form of jet fuel containing the additive FM-9, known as "[[Antimisting kerosene]]" (AMK), which formed a hard-to-ignite gel when agitated violently, as in a crash. ''See [[Controlled Impact Demonstration]].'']]
[[Human factors]] including [[pilot error]] are another potential danger, and currently the most common factor of aviation crashes. Much progress in applying human factors to improving aviation safety was made around the time of [[World War II]] by people such as [[Paul Fitts]] 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.<ref>[http://www.atchistory.org/History/checklst.htm How the Pilot's Checklist Came About]</ref> Pilot error and improper communication are often factors in the [[collision]] of aircraft. This can take place [[mid-air collision|in the air]] (1978 [[Pacific Southwest Airlines]] [[PSA Flight 182|Flight 182]]) ([[TCAS]]) or on the ground (1977 [[Tenerife disaster]]) ([[Runway Awareness and Advisory System|RAAS]]). The ability of the flight crew to maintain [[situational awareness]] 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 resulted in the crash of [[Eastern Air Lines]] [[Eastern Air Lines Flight 401|Flight 40]] in 1972 ([[CFIT]]), and error during take-off and landing can have catastrophic consequences, for example cause the crash of [[Prinair]] [[Prinair Flight 191|Flight 191]] on landing, also in 1972.

Rarely, flight crew members are arrested or subject to disciplinary action for being [[Drunkenness|intoxicated]] on the job. In 1990, three [[Northwest Airlines]] crew members were sentenced to jail for flying from [[Fargo, North Dakota]] to [[Minneapolis-Saint Paul International Airport]] while drunk. In 2001, Northwest fired a pilot who failed a [[breathalyzer]] test after flying from [[San Antonio, Texas]] to Minneapolis-Saint Paul. In July 2002, two [[America West Airlines]] pilots were arrested just before they were scheduled to fly from [[Miami, Florida]] to [[Phoenix, Arizona]] because they had been drinking [[alcohol]]. The pilots have been fired from America West and the FAA revoked their pilot's licenses. As of 2005 they await trial in a Florida court.<ref>[http://sptimes.com/2005/02/01/State/Court_blocks_doctors_.shtml U.S. drops prosecution of allegedly tipsy pilots (second story)]</ref> The incident created a public relations problem and America West has become the object of many jokes about drunk pilots. At least one fatal airliner accident involving drunk pilots has occurred when [[Aero Flight 311]] crashed killing all 25 on board in 1961, which underscores the role that poor human choices can play in air accidents.

Human factors incidents are not limited to errors by the pilots. The failure to close a cargo door properly on [[Turkish Airlines]] [[Turkish Airlines Flight 981|Flight 981]] in 1974 resulted in the loss of the aircraft - however the design of the cargo door latch was also a major factor in the incident. In the case of [[Japan Airlines]] [[Japan Airlines Flight 123|Flight 123]], improper maintenance resulted in the loss of the [[vertical stabilizer]].

====Controlled flight into terrain====
{{Main|Controlled flight into terrain}}

Controlled flight into terrain is a class of accident in which an undamaged aircraft is flown, under control, into terrain or man-made structures. CFIT accidents typically are a result of pilot error or of navigational system error. Some pilots, convinced that advanced electronic navigation systems such as GPS and [[inertial guidance system]]s (inertial navigation system or INS) coupled with [[flight management system]] computers , or over-reliance on them, are partially responsible for these accidents, have called CFIT accidents "computerized flight into terrain". Failure to protect Instrument Landing System [[critical area]]s can also cause controlled flight into terrain. One of the most notable CFIT accidents was in December 1995 in which [[American Airlines flight 965]] tracked off course while approaching Calí, Colombia and hit a mountainside after the speedbrakes were left deployed despite an aural terrain warning in the cockpit and an attempt to gain ample altitude in the nighttime contidions. Crew awareness and monitoring of navigational systems can prevent or eliminate CFIT accidents. [[Crew Resource Management]] is a modern method now widely used to improve the human factors of air safety. The [[Aviation Safety Reporting System]], or ASRS is another.

Other technical aids can be used to help pilots maintain situational awareness. A [[ground proximity warning system]] is an on-board system that will alert a pilot if the aircraft is about to fly into the ground. Also, [[air traffic controller]]s constantly monitor flights from the ground and at airports.

====Terrorism====
{{Main|Terrorism}}

Terrorism can also be considered a human factor. Crews are normally trained to handle [[Aircraft hijacking|hijack]] situations. Prior to the [[September 11, 2001 attacks]], hijackings involved hostage negotiations. After the September 11, 2001 attacks, stricter [[airport security]] measures are in place to prevent terrorism using a [[Computer Assisted Passenger Prescreening System]], [[Federal Air Marshal Service|Air Marshal]]s, and precautionary policies. In addition, [[Counter-terrorism|counter-terrorist]] organizations monitor potential terrorist activity.

Although most air crews are screened for psychological fitness, some may take suicidal actions. In the case of [[EgyptAir Flight 990]], it appears that the [[First Officer (civil aviation)|first officer]] deliberately dived his aircraft into the [[Atlantic Ocean]] while the captain was away from his station, in 1999 off [[Nantucket, Massachusetts]]. Motivations are unclear, but recorded inputs from the [[Black box (transportation)|black boxes]] showed no mechanical problem, no other aircraft in the area, and was corroborated by the [[cockpit voice recorder]]. 

The use of certain electronic equipment is partially or entirely prohibited as it may interfere with aircraft operation, such as causing [[compass]] deviations. Use of personal electronic devices and [[calculator]]s may be prohibited when an aircraft is below 10,000', taking off, or landing. The American [[Federal Communications Commission]] (FCC) prohibits the use of a [[Mobile phone|cell phone]] on most flights, because in-flight usage creates problems with ground-based cells.{{Citation needed|date=February 2010}} There is also concern about possible interference with aircraft navigation systems, although that has never been proven to be a non-serious risk on airliners. A few flights now allow use of cell phones, where the aircraft have been specially wired and certified to meet both FAA and FCC regulations.

====Attack by a hostile country====
Aircraft, whether passenger planes or military aircraft, are sometimes attacked in both peacetime and war. Notable examples of this are:
* On February 21, 1973 [[Libyan Arab Airlines Flight 114]] [[727-224]] entered the then-[[Israel]]i-controlled airspace over the [[Sinai Peninsula]], was intercepted by two Israeli [[F-4 Phantom IIs]] and shot down while trying to re-enter Egyptian airspace after failing to follow instructions issued by the Israeli pilots. Of the 113 people on board, there were 5 survivors, including the co-pilot.
* 1 September 1983 downing by the Soviet Union of [[Korean Air Lines Flight 007]], carrying 269 people (including a sitting U.S. Congressman [[Larry McDonald]]),
* 3 July 1988 shoot-down by [[United States Navy]] of [[Iran Air Flight 655]], carrying 290 people.
* 4 November 2001 shoot-down by Ukrainian Air Force of Russian [[flight 1812]] (Tel-Aviv - Novosibirsk), carrying 78 people.

===Airport design===
Airport design and location can have a big impact on air 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 {{ft to m|500}} to each side and {{ft to m|1000}} 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. Since this is a recent rule, many airports do not meet it. One method of substituting for the {{ft to m|1000}} at the end of a runway for airports in congested areas is to install an [[Engineered materials arrestor system]], or 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 (as of 2005) at [[John F. Kennedy International Airport|JFK Airport]].

===Infection===

On an airplane, people sit in a confined space for extended periods of time, which increases the risk of transmission of airborne infections.<ref name="Mangili2005">{{cite journal | author=Mangili A, Gendreau MA | title=Transmission of infectious diseases during commercial air travel | journal=Lancet | year=2005 | volume=365 | pages=989&ndash;96 | pmid=15767002  | doi=10.1016/S0140-6736(05)71089-8 | issue=9463}}</ref><ref>{{cite journal | author=Leder K, Newman D | title=Respiratory infections during air travel | journal=Intern Med J | year=2005 | volume=35 | apges=50&ndash;5 | pmid=15667469 | pages=50 | doi=10.1111/j.1445-5994.2004.00696.x | issue=1}}</ref> For this reason, airlines place restrictions on the travel of passengers with known airborne contagious diseases (e.g. [[tuberculosis]]). During the [[severe acute respiratory syndrome]] (SARS) epidemic of 2003, awareness of the possibility of acquisition of infection on a commercial aircraft reached its zenith when on one flight from [[Hong Kong]] to [[Beijing]], 16 of 120 people on the flight developed proven SARS from a single [[Index case (medicine)|index case]].<ref>{{cite journal | author=Olsen SJ, Chang HL, Cheung TY, ''et al.'' | title=Transmission of the severe acute respiratory syndrome on aircraft | journal=N Engl J Med | year=2003 | volume=349 | pages=2416&ndash;22 | pmid=14681507  | doi=10.1056/NEJMoa031349 | issue=25}}</ref>

There is very limited research done on [[Infectious disease|contagious diseases]] on aircraft. The two most common [[Respiratory system|respiratory]] [[pathogen]]s to which air passengers are exposed are [[Human parainfluenza viruses|parainfluenza]] and [[influenza]].<ref>{{cite journal | author=Luna LK, Panning M, Grywna K, Pfefferle S, Drosten C | title=Spectrum of viruses and atypical bacteria in intercontinental air travelers with symptoms of acute respiratory infection | journal=J Infect Dis | year=2007 | volume=195 | pages=675&ndash;9 | pmid=17262708  | doi=10.1086/511432 | issue=5}}</ref> In one study, the flight ban imposed following the attacks of September 11, 2001 was found to have restricted the global spread of seasonal influenza, resulting in a much milder influenza season that year,<ref>{{cite journal | author=Brownstein JS, Wolfe CJ, Mandl KD | title=Empirical evidence for the effect of airline travel on inter-regional influenza spread in the United States | journal=PLoS Med | year=2006 | volume=3 | pages=3401 | pmid=16968115  | doi=10.1371/journal.pmed.0030401 | issue=10 | pmc=1564183}}</ref> and the ability of influenza to spread on aircraft has been well documented.<ref name="Mangili2005"/> There is no data on the relative contributions of large droplets, small particles, close contact, surface contamination, and no data on the relative importance of any of these methods of transmission for specific diseases, and therefore very little information on how to control the risk of infection. There is no standardisation of air handling by aircraft, installation of [[HEPA]] filters or of hand washing by air crew, and no published information on the relative efficacy of any of these interventions in reducing the spread of infection.<ref>{{cite journal|author=Pavia, Andrew T.|title=Germs on a Plane: Aircraft, International Travel, and the Global Spread of Disease|journal=Journal of Infectious Diseases|year=2007|volume=195|pages=621&ndash;22|url=http://www.journals.uchicago.edu/doi/pdf/10.1086/511439?cookieSet=1|doi=10.1086/511439|format=pdf|pmid=17262701|issue=5}}</ref>

===Emergency airplane evacuations===

According to a 2000 report by the National Transportation Safety Board, emergency airplane 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 airplane slide.  In a TIME article on the subject, Amanda Ripley reported that when a new supersized Airbus A380 underwent mandatory evacuation tests in 2006, 33 of the 873 evacuating volunteers got hurt.  While the evacuation was generally considered a success, one volunteer suffered a broken leg, while the remaining 32 received slide burns.  Such accidents are common.  In her article, Ripley provides tips on how to make it down the airplane slide without injury.<ref>[http://www.time.com/time/nation/article/0,8599,1706188,00.html How to Escape Down an Airplane Slide - and Still Make Your Connection!] Amanda Ripley. TIME. January 23, 2008.</ref>

=== Runway safety ===

{{Main|Runway#Runway_safety}}

Several terms fall under the [[flight safety]] topic of '''runway safety''', including '''incursion, excursion,''' and '''confusion'''.

'''Runway excursion''' is an incident involving only a single aircraft, where it makes an inappropriate exit from the runway.  This can happen because of pilot error, poor weather, or a fault with the aircraft.{{Citation needed|date=December 2008}}  '''Overrun''' is a type of excursion where the aircraft is unable to stop before the end of the runway.  A recent example of such an event is [[Air France Flight 358]] in 2005.  Further examples can be found in the [[:Category:Runway overruns|overruns category]].

'''Runway event''' is another term for a '''runway accident'''.{{Citation needed|date=December 2008}}

'''[[Runway incursion]]''' involves a first aircraft, as well as a second aircraft, vehicle, or person.  It is defined by the U.S. FAA as: "Any occurrence at an aerodrome involving the incorrect presence of an aircraft, vehicle or person on the protected area of a surface designated for the landing and take off of aircraft."<ref>http://www.faa.gov/runwaysafety/ FAA Runway Safety webpage, Retrieved 2008-12-14.</ref>

'''Runway confusion''' involves a single aircraft, and is used to describe the error when the aircraft makes "the unintentional use of the wrong runway, or a [[taxiway]], for landing or take-off".<ref>http://www.flightglobal.com/articles/2008/03/14/222239/comment-safety-excursions.html "Safety Excursions", FlightGlobal.com, Retrieved 2008-12-15.</ref> An example of a runway confusion incident is [[Comair Flight 191]].

'''Runway excursion''' is the most frequent type of landing accident, slightly ahead of '''runway incursion'''.<ref name="run-excur">http://www.flightglobal.com/articles/2008/03/14/222223/runway-excursion-most-frequent-type-of-landing-accident-flight-safety.html "Runway excursion most frequent type of landing accident: Flight Safety Foundation " FlightGlobal.com, Retrieved 2008-12-14.</ref>  For runway accidents recorded between 1995 and 2007, 96% were of the 'excursion' type.<ref name="run-excur" />

The U.S. FAA publishes an lengthy annual report on runway safety issues, available from the FAA website [http://www.faa.gov/runwaysafety/publications.cfm here].  New systems designed to improve runway safety, such as [[Airport Movement Area Safety System]] (AMASS) and [[Runway Awareness and Advisory System]] (RAAS), are discussed in the report.  AMASS prevented the serious near-collision in the [[2007 San Francisco International Airport runway incursion]].

==Accidents and incidents==
*[[List of airship accidents]]
*[[:Category:Lists of aviation accidents and incidents|Lists of aviation accidents and incidents]]
*[[Aviation accidents and incidents]]
*[[Flight recorder]], includes ''flight data recorder'' and ''cockpit voice recorder''

===Statistics===

There are three main statistics which may be used to compare the safety of various forms of travel:<ref>[http://dspace.dial.pipex.com/town/square/ca14/ALYCIDON%20RAIL/INFORMED%20SOURCES%20ARCHIVE/INF%20SRCS%202000/Informed%20Sources%2010%202000.htm Informed Sources Archive] Alycidon Rail web site. Retrieved 29 April 2009. The site cites the source as an October 2000 article by Roger Ford in the magazine ''[[Modern Railways]]'' and based on a DETR survey.</ref>

{| class="wikitable" style="width: 16em; display: inline-table;"
! colspan=2 | Deaths per billion passenger-journeys 
|-
| [[Bus]] || 4.3
|-
| [[Rail transport|Rail]] || 20
|-
| [[Van]] || 20
|-
| [[Car]] || 40
|-
| [[Walking|Foot]] || 40
|-
| [[Ship transport|Water]] || 90
|-
| '''Air''' || 117
|-
| [[Bicycle]] ||  170
|-
| [[Motorcycle]] || 1640
|}

{| class="wikitable" style="width: 16em; display: inline-table;"
! colspan=2 | Deaths per billion passenger-hours 
|-
| [[Bus]] || 11.1
|-
| [[Rail transport|Rail]] || 30
|-
| '''Air''' || 30.8
|-
| [[Ship transport|Water]] || 50
|-
| [[Van]] || 60
|-
| [[Car]] || 130
|-
| [[Walking|Foot]] || 220
|-
| [[Bicycle]] || 550
|-
| [[Motorcycle]] || 4840
|}

{| class="wikitable" style="width: 18em; display: inline-table;"
! colspan=2 | Deaths per billion passenger-kilometres 
|-
| '''Air''' || 0.05
|-
| [[Bus]] || 0.4
|-
| [[Rail travel|Rail]] || 0.6
|-
| [[Van]] || 1.2
|-
| [[Ship transport|Water]] || 2.6
|-
| [[Car]] || 3.1
|-
| [[Bicycle]] || 44.6
|-
| [[Walking|Foot]] || 54.2 
|-
| [[Motorcycle]] || 108.9
|}

It is worth noting that the air industry's insurers base their calculations on the ''number of deaths per passenger-journey'' statistic while the industry itself generally uses the ''number of deaths per passenger-kilometre'' statistic in press releases.<ref>[http://space.newscientist.com/article/mg16321985.200-flight-into-danger.html Flight into danger - 07 August 1999 - New Scientist Space<!-- Bot generated title -->]</ref> However, considering the "number of deaths per passenger-journey" statistic, it should also be noted that an average person makes far fewer number of journeys by the air than by car, bus or train in a year.

===Investigators===
* [[Australian Transport Safety Bureau]]
* [http://www.bmvit.gv.at/verkehr/luftfahrt/behoerden/fusbmvit.html Flugunfalluntersuchungsstelle im BMVIT] (Austria)
* [[Transportation Safety Board of Canada]]
* [http://www.uzpln.cz/ Air Accidents Investigation Institute of the Czech Republic]
* [http://www.hcl.dk/ 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)
* [[Aircraft and Railway Accidents Investigation Commission]] (Japan)
* [[Civil Aviation Authority of New Zealand]]
* [[Transport Accident Investigation Commission]] (New Zealand)
* [[Comisión de Investigación de Accidentes e Incidentes de Aviación Civil]] (Spain)
* [[Swedish Accident Investigation Board]]
* [http://www.bfu.admin.ch Büro für Flugunfalluntersuchung] (Switzerland)
* [[Air Accidents Investigation Branch]] (UK)
* [[National Transportation Safety Board]] (USA)
* [http://eccairs-www.jrc.it/ European Co-ordination Center for Aircraft Incident Reporting Systems] (ECCAIRS)
* [[International Civil Aviation Organisation]]

==Safety Improvement Initiatives==
The Safety Improvement Initiatives are aviation safety partnerships between regulators, manufacturers, operators and professional unions, research organisations, international organisations to further enhance safety.
The major Safety initiatives worldwide are:
*[http://www.cast-safety.org/ '''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. 
* [http://easa.europa.eu/essi/webapp/essi/www/index.php '''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.

==Regulation==
* [[Department of Infrastructure, Transport, Regional Development and Local Government]] ([[Australia]])
* [[Transport Canada]]
* [[European Aviation Safety Agency]]
* [[Irish Aviation Authority]]
* [[Civil Aviation Authority (United Kingdom)|Civil Aviation Authority]] ([[United Kingdom]])
* [[Federal Aviation Administration]] ([[United States]])
** [[Federal Aviation Regulations]]

==See also==
{{Portal|Aviation}}
{{Wikipedia-Books|Aviation}}
* [[Aerospace engineering]]
* [[Aircraft]]
* [[Aircraft hijacking]]
* [[Aircraft safety card]]
* [[Airline complaints]]
* [[Airport security]]
* [[Avionics]]
* [[Avionics software]]
* [[Aviation]]
* [[Aviation archaeology]]
* [[Aviation history]]
* [[Aviation Safety Network]]
* [[Aviation Safety Reporting System]]
* [[Ballistic Recovery Systems]]
* [[Canadian Air Transport Security Authority]]
* [[Counter terrorism]] 
* [[Charlie Victor Romeo]]
* [[Crashworthiness]]
* [[Department of Homeland Security]]
* [[Emergency aircraft evacuation]]
* [[Federal Air Marshal Service]]
* [[Federal Flight Deck Officer]]
* [[Flight planning]]
* [[Flight training]]
* ''[[Ferguson v. NTSB]]''
* [[General aviation]] ([[General aviation in Europe|in Europe]])
* [[Hazard analysis]]
* [[Human reliability]]
* [[IATA Operational Safety Audit]]
* [[Pre-flight safety demonstration]]
* [[Preflight Planning Dispatch Checklist]]
* [[JACDEC|Jet Airliner Crash Data Evaluation Centre]]
* [[Lasers and aviation safety]]
* [[List of air carriers banned in the European Union]]
* [[Mid-air collision]]
* [[NASA]]
* [[Pilot error]]
* [[Road traffic safety]]
* [[Safety of emergency medical services flights]]
* [[SKYbrary]]
* [[Swiss Cheese model]]
* [[Terrorism]]
* [[Transportation Security Administration]]
* [[Tombstone mentality]]
* [[Transportation safety in the United States]]
* [[Wind shear]]

==Notes==
{{Reflist|2}}

==External links==
*{{dmoz|Science/Technology/Aerospace/Aeronautics/Safety_of_Aviation/|Air Safety}}
*[http://www.skybrary.aero/index.php/Portal:Safety_Behaviours_-_Guide_for_Pilots Safety Behaviours, a guide for pilots (comprehensive human factors information)]
*[http://asrs.arc.nasa.gov/ NASA Aviation Safety Reporting System (ASRS)]
*[http://www.airdisaster.com/ Airdisaster] - Database of Airborne Accidents
*[http://aviation-safety.net/ Latest Aviation Safety Occurrences at the Aviation Safety Network]
*[http://www.gao.gov/atext/d0433.txt Aviation Safety: Advancements Being Pursued to Improve Airliner Cabin Occupant Safety and Health, 2003]
* [[Frontline (U.S. TV series)]] - [http://www.pbs.org/wgbh/pages/frontline/flyingcheap/ Flying Cheap] - February 9, 2010. One year after the deadly crash of [[Colgan Air Flight 3407|Continental 3407]], FRONTLINE investigate the safety issues associated with [[regional airline]]s.

{{DEFAULTSORT:Air Safety}}
[[Category:Air safety]]
[[Category:Occupational safety and health]]

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