View source for Spatial disorientation

{{short description|Inability of a person to correctly determine their body position in space}}
'''Spatial disorientation''' is the inability to determine position or relative motion, commonly occurring during periods of challenging visibility, since [[visual system|vision]] is the dominant sense for orientation. The [[auditory system]], [[vestibular system]] (within the [[inner ear]]), and [[proprioceptive system]] (sensory receptors located in the skin, muscles, tendons and joints) collectively work to coordinate movement with balance, and can also create illusory nonvisual sensations, resulting in spatial disorientation in the absence of strong visual cues.

In aviation, spatial disorientation can result in improper perception of the [[Orientation (geometry)|attitude]] of the aircraft, referring to the orientation of the aircraft relative to the horizon.  If a pilot relies on this improper perception, this can result in inadvertent turning, ascending or descending. For aviators, proper recognition of aircraft attitude is most critical at night or in poor weather, when there is no visible horizon; in these conditions, aviators may determine aircraft attitude by reference to an [[attitude indicator]]. Spatial disorientation can occur in other situations where visibility is reduced, such as diving operations.

== Flight safety, history, and statistics ==
[[File:Barany Chair equilibrium test.jpg|thumb|right|Equilibrium test being administered to prospective pilot, via [[Bárány chair]]]]{{Further|Sensory illusions in aviation}}
Spatial orientation in flight is difficult to achieve because numerous sensory stimuli (visual, vestibular, and proprioceptive) vary in magnitude, direction, and frequency. Any differences or discrepancies between visual, vestibular, and proprioceptive sensory inputs result in a sensory mismatch that can produce illusions and lead to spatial disorientation. The visual sense is considered to be the largest contributor to orientation.<ref name=ATSB-SD2007/>{{rp|4}}

While testing an early [[turn and slip indicator]] devised by his friend [[Elmer Sperry]] in 1918, [[United States Army Air Corps]] pilot [[William Ocker]] entered a [[graveyard spiral]] while flying through clouds without visual references; the turn indicator showed he was in a turn, but his senses told him he was in level flight. Emerging from the clouds, Ocker was able to recover from the dive.<ref>{{cite journal |url=https://www.inventionandtech.com/content/father-blind-flying-0 |title=The Father Of Blind Flying |date=Fall 2008 |author=Wolverton, Mark |volume=23 |issue=3 |journal=Invention and Technology |access-date=11 February 2021 |publisher=American Heritage Institute}}</ref> In 1926, Ocker was subjected to a [[Bárány chair]] equilibrium test by Dr. [[David A. Myers]] at [[Crissy Field]]; the resulting duplication of the somatogyral illusion he had experienced and a subsequent re-test, which he passed using the turn indicator,<ref name=AFEHRI-Ocker>{{cite web |url=https://www.airuniversity.af.edu/Portals/10/AFEHRI/documents/EnlistedHistory/ocker.pdf |title=Sergeant William Charles Ocker: The Army's third enlisted pilot |author=Chivalette, William I. |publisher=Air Force Enlisted Heritage Research Institute |date=1998 |access-date=11 February 2021}}</ref> led him to develop and champion instrumented flight.<ref name=AS-2008/> Sperry would go on to invent the [[gyrocompass]] and [[attitude indicator]], both of which were being tested by 1930.<ref name=ACSC-88>{{cite report |url=https://apps.dtic.mil/dtic/tr/fulltext/u2/a194001.pdf |archive-url=https://web.archive.org/web/20191101162824/https://apps.dtic.mil/dtic/tr/fulltext/u2/a194001.pdf |url-status=live |archive-date=November 1, 2019 |title=The evolution of instrument flying in the U.S. Army |author=McIntosh, David M. |date=1988 |publisher=Air Command and Staff College |access-date=11 February 2021}}</ref>{{rp|8}} With Lt. Carl Crane, Ocker published the instructional text ''Blind Flying in Theory and Practice'' in 1932.<ref name=AS-2008>{{cite magazine |url=https://www.airspacemag.com/military-aviation/the-disorient-express-474780/?all |title=The Disorient Express |author=LeCompte, Tom |date=September 2008 |magazine=Air & Space |publisher=Smithsonian Institution |access-date=11 February 2021}}</ref> Influential advocates of instrumented flight training included [[Albert Hegenberger]] and [[Jimmy Doolittle]].<ref name=ACSC-88/>{{rp|8}}

In 1965, the [[Federal Aviation Agency]] of the United States issued Advisory Circular AC 60-4, warning pilots about the hazards of spatial disorientation, which may result from operation under [[visual flight rules]] in conditions of marginal visibility.<ref name=AC60-4>{{cite web |url=https://dotlibrary.specialcollection.net/Document?db=DOT-ADVISORY&query=(select+198) |title=AC 60-4: Pilot's Spatial Disorientation |author=Moore, George S. |date=February 9, 1965 |publisher=Federal Aviation Agency |access-date=11 February 2021}}</ref> A new version of the advisory was issued in 1983 as AC 60-4A, defining spatial disorientation as "the inability to tell which way is 'up.{{' "}}<ref name=AC60-4A>{{cite web |url=https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC60-4A.pdf |title=AC 60-4A: Pilot's Spatial Disorientation |author=Hunt, Kenneth S. |date=February 9, 1983 |publisher=Federal Aviation Administration |access-date=11 February 2021}}</ref>

Statistics show that between 5% and 10% of all general aviation accidents can be attributed to spatial disorientation, 90% of which are fatal.<ref name=FAA-spatial>{{cite web |url=https://www.faa.gov/pilots/safety/pilotsafetybrochures/media/spatiald.pdf |title=Medical Facts for Pilots: Spatial Disorientation, safety brochure AM-400-03/1 |author=Antuñano, Melchor J. |access-date=9 February 2021 |publisher=Federal Aviation Administration}}</ref> Spatial-D and [[G-LOC|G-force induced loss of consciousness (g-LOC)]] are two of the most common causes of death from human factors in military aviation.<ref name=Jedick>{{cite web |url=http://goflightmedicine.com/spatial-disorientation/ |title=Spatial Disorientation |author=Jedick, Rocky 'Apollo' |publisher=Go Flight Medicine |date=1 April 2013 |access-date=30 July 2016}}</ref> A study on the prevalence of spatial disorientation incidents concluded that "if a pilot flies long enough ... there is no chance that he/she will escape experiencing at least one episode of [spatial disorientation]. Looked at another way, pilots can be considered to be in one of two groups; those who have been disorientated, and those who will be."<ref name=ATSB-SD2007>{{cite report |url=https://www.atsb.gov.au/media/29971/b20070063.pdf |title=An overview of spatial disorientation as a factor in aviation accidents and incidents |author=Newman, David G. |date=3 December 2007 |publisher=Australian Transport Safety Bureau |isbn=978-1-921165-52-8 |access-date=11 February 2021 |archive-date=19 September 2020 |archive-url=https://web.archive.org/web/20200919000527/https://www.atsb.gov.au/media/29971/b20070063.pdf |url-status=dead }}</ref>{{rp|2}}

== Physiology ==
There are four physiologic systems that interact to allow humans to orient themselves in space. Vision is the dominant sense for orientation, but the vestibular system, proprioceptive system and auditory system also play a role.{{cn|date=June 2022}}

Spatial orientation (the inverse being spatial disorientation, aka ''spatial-D'') is the ability to maintain body orientation and posture in relation to the surrounding environment (physical space) at rest and during motion. Humans have evolved to maintain spatial orientation on the ground. Good spatial orientation on the ground relies on the use of visual, auditory, vestibular, and proprioceptive sensory information. Changes in linear acceleration, angular acceleration, and gravity are detected by the vestibular system and the proprioceptive receptors, and then compared in the brain with visual information.{{cn|date=June 2022}}

The three-dimensional environment of flight is unfamiliar to the human body, creating sensory conflicts and illusions that make spatial orientation difficult and sometimes impossible to achieve. The result of these various visual and nonvisual illusions is spatial disorientation.<ref>{{cite book |last1=Previc |first1=Fred H. |last2=Ercoline |first2=William R. |date=2004 |title=Spatial disorientation in aviation |location=Reston, Virginia |publisher=American Institute of Astronautics and Aeronautics |isbn=978-1-60086-670-8 |doi=10.2514/4.866708}}</ref><ref name=Jedick/><ref>{{cite web|url=http://www.britannica.com/EBchecked/topic/558427/spatial-disorientation|title=Spatial disorientation - physiology |website=Britannica |access-date=30 July 2016}}</ref> Various models have been developed to yield quantitative predictions of disorientation associated with known aircraft accelerations.<ref>{{cite conference |last1=Newman |first1=Michael C. |last2=Lawson |first2=Ben D. |last3=Rupert |first3=Angus H. |last4=McGrath |first4=Braden J. |title=AIAA Modeling and Simulation Technologies Conference |date=August 13–16, 2012 |chapter=The role of perceptual modeling in the understanding of spatial disorientation during flight and ground-based simulator training |conference=AIAA modeling and simulation technologies conference |location=Minneapolis, Minnesota |doi=10.2514/6.2012-5009 |publisher=American Institute of Aeronautics and Astronautics|isbn=978-1-62410-183-0 }}</ref>

== The vestibular system and sensory illusions ==
{{main|Sensory illusions in aviation}}
[[File:Blausen 0329 EarAnatomy InternalEar.png|thumb|right|upright=1.5|Inner ear]]
The vestibular system detects linear and angular (rotational) acceleration using specialized organs in the inner ear. Linear accelerations are detected by the [[otolith organs]], while angular accelerations are detected by the [[semicircular canals]].

=== Misleading sensations ===
Without a visual reference or cues, such as a visible horizon, humans will rely on non-visual senses to establish their sense of motion and equilibrium. During the abnormal acceleratory environment of flight, the [[Vestibular system|vestibular]] and [[proprioceptive system]]s can be misled, resulting in spatial disorientation. When an aircraft is maneuvering, inertial forces can be created by changes in vehicle speed (linear acceleration) and/or changes in direction (rotational acceleration and [[centrifugal force]]), resulting in perceptual misjudgment of the vertical, as the combined forces of gravity and inertia do not align with what the vestibular system assumes is the vertical direction of gravity (towards the center of the Earth).

Under ideal conditions, visual cues will provide sufficient information to override illusory vestibular inputs, but at night or in poor weather, visual inputs can be overwhelmed by these illusory nonvisual sensations, resulting in spatial disorientation. Low visibility flight conditions include night,<ref name=AC60-4/> over water or other monotonous/featureless terrain that blends into the sky,<ref name=AC60-4/> [[Whiteout (weather)|white-out weather]],<ref name=AC60-4/> or inadvertent entry into [[instrument meteorological conditions]] after flying into fog or clouds.

[[File:Load factor and the g-force in turn.svg|thumb|left|Lift (L) and weight/gravity (w) forces acting on an aircraft making a banked or coordinated turn]]
For example, in an aircraft that is making a [[Banked turn#Banked turn in aeronautics|coordinated (banked) turn]], no matter how steep, occupants will have little or no sensation of being tilted in the air unless the horizon is visible, as the combined forces of lift and gravity are felt as pressing the occupant into the seat without a lateral force sliding them to either side.<ref>{{cite news |url=https://japantoday.com/category/national/ana-pilots-unaware-for-20-seconds-that-plane-was-almost-turning-upside-down |title=ANA pilots unaware for 17 seconds that plane was almost turning upside down |date=August 31, 2012 |work=Japan Today |access-date=11 February 2021 |quote=The aircraft tipped more than 130 degrees to the left at one point, but the darkness outside meant many of those on board did not realize the craft had almost flipped over.}}</ref> Similarly, it is possible to gradually climb or descend without a noticeable change in pressure against the seat. In some aircraft, it is possible to execute a loop without pulling negative g-forces so that, without visual reference, the pilot could be upside down without being aware of it.{{Citation needed|date=March 2011}} A gradual change in any direction of movement may not be strong enough to activate the vestibular system, so the pilot may not realize that the aircraft is accelerating, decelerating, or banking.

[[File:BASIC_Flight_instruments_Improved.svg|thumb|right|Standard set of [[flight instruments]], including [[attitude indicator]] (top center) and [[turn and slip indicator]] (bottom left)]]
Gyroscopic [[flight instruments]] such as the [[attitude indicator]] (artificial horizon) and the [[turn and slip indicator]] are designed to provide information to counteract misleading sensations from the non-visual senses.

===Otoliths and somatogravic illusions===
Two otolith organs, the saccule and utricle, are located in each ear and are set at right angles to each other. The utricle detects changes in linear acceleration in the horizontal plane, while the saccule detects linear accelerations in the vertical plane; humans have evolved to assume the vertical acceleration is caused by gravity. However, the saccule and utricle can provide misleading sensory perception when gravity is not limited to the vertical plane, or when vehicle speeds and accelerations result in inertial forces comparable to the force of gravity, as the otoliths only detect acceleration, and cannot distinguish inertial forces from the force of gravity.<ref name=FAA-spatial/> Some examples of this include the inertial forces experienced during a vertical take-off in a helicopter or following the sudden opening of a parachute after a free fall.{{cn|date=June 2022}}

Illusions caused by the otolith organs are called somatogravic illusions and include the Inversion, Head-Up, and Head-Down Illusions. The Inversion Illusion results from a steep ascent followed by a sudden return to level flight; the resulting relative increase in forward speed produces an illusion the aircraft is inverted.<ref name=FAA-spatial/> The Head-Up and Head-Down illusions are similar, involving sudden linear acceleration (Head-Up) or deceleration (Head-Down), leading to a misperception the nose of the aircraft is pitching up (Head-Up) or down (Head-Down); the aviator could be fooled into pitching the nose down (Head-Up) or up (Head-Down) in response, leading to a crash or a stall, respectively.<ref name=FAA-spatial/>

Typically, the Head-Up illusion occurs during take-off, as a strong linear acceleration is used to generate lift over the wing and flaps. Without a visual reference, the pilot may assume from the vestibular system the nose has pitched up and command a dive; if this occurs during take-off, the aircraft may not have sufficient altitude to recover before crashing into the ground.<ref name=ATSB-SD2007/>{{rp|7}}

===Semicircular canals and somatogyral illusions===
[[Image:innernvestib.jpg|thumb|right|[[Inner ear]] with semicircular canals shown, likening them to the roll, pitch and yaw axis of an aircraft]]
In addition, the inner ear contains rotational [[accelerometer]]s, known as the semicircular canals, which provide information to the lower brain on rotational accelerations in the [[flight dynamics|pitch, roll and yaw axes]]. Changes in angular velocity are detected from the relative motion between the fluid in the canals and the canal itself, which is fixed to the head; because of inertia, the fluid in the canals tends to lag when the head moves, signaling a rotational acceleration. However, semicircular canal output ceases after prolonged rotation (beyond {{val|15|-|20|u=s}}) as the fluid has now been entrained into motion through friction, matching the motion of the head. If the rotation is then stopped, the perceived motion signal from the inner ear indicates the aviator is now turning in the opposite direction from actual travel, as the fluid continues to move while the canal has stopped.<ref name=FAA-spatial/> In addition, the inertia of the fluid means the detection threshold of rotational acceleration is limited to approximately 2°/sec{{sup|2}}; angular accelerations below this value cannot be detected.<ref name=ATSB-SD2007/>{{rp|5}} Specific common somatogyral illusions induced by the semicircular canals are the Leans, Graveyard Spin, Graveyard Spiral, and Coriolis.

{{main|The leans}}
If the aircraft enters an unnoticed, prolonged turn gradually, then suddenly returns to level flight, [[the leans]] may result. The gradual turn sets the fluid into the semicircular canals into motion, and rotational acceleration of two degrees per second (or less) cannot be detected. Once the aircraft suddenly returns to level flight, the continued fluid motion gives the sensation the aircraft is banking in the opposite direction of the turn that just ended; the aviator may attempt to correct the misperception of the vertical by banking into the original turn.<ref name=FAA-spatial/> The leans is considered the most common form of spatial disorientation.<ref name=ATSB-SD2007/>{{rp|9}}

{{main|Graveyard spiral|Graveyard spin}}
[[File:FAA PHAK 2008 Fig 16-5 Graveyard spiral.png|thumb|right|Graveyard spiral and graveyard spin]]
The [[graveyard spiral]] and [[graveyard spin]] are both caused by the acclimation of the semicircular canals to prolonged rotation; after a banked turn (in the case of the graveyard spiral) or spin (for the graveyard spin) of approximately 20 seconds, the fluid in the semicircular canals has been entrained into motion by friction, and the vestibular system no longer perceives a rotational acceleration. If the aviator then ends the turn or spin and returns to level flight, the continued motion of the fluid will cause a sensation the aircraft is turning or spinning in the opposite direction, and the pilot may re-enter the original turn or spin inadvertently; the aviator may not recognize the illusion before the aircraft loses too much altitude, resulting in a collision with terrain<ref name=FAA-spatial/> or the [[g-force]]s on the aircraft may exceed the structural strength of the [[airframe]], resulting in catastrophic failure. One of the most infamous mishaps in aviation history involving the graveyard spiral is [[John F. Kennedy Jr. plane crash|the crash involving John F. Kennedy Jr.]] in 1999.<ref name="auto">{{Cite web |url=https://goflightmedicine.com/jfk-jr-piper-saratoga-mishap/ |title=JFK Jr Piper Saratoga Mishap |author=Jedick, Rocky 'Apollo' |publisher=Go Flight Medicine |date=April 15, 2014}}</ref>

Once an aircraft enters conditions under which the pilot cannot see a distinct visual horizon, the drift in the inner ear continues uncorrected.  Errors in the perceived rate of turn about any axis can build up at a rate of 0.2 to 0.3 degrees per second.{{citation needed|date=July 2016}}  If the pilot is not proficient in the use of gyroscopic flight instruments, these errors will build up to a point that control of the aircraft is lost, usually in a steep, diving turn known as a [[graveyard spiral]].  During the entire time, leading up to and well into the maneuver, the pilot remains unaware of the turning, believing that the aircraft is maintaining straight flight.<ref>{{cite book |url=https://books.google.com/books?id=wjVPDwAAQBAJ&pg=PA125 |title=VPNavy! USN, USMC, USCG and NATS Patrol Aircraft Lost or Damaged During World War II |author=Campbell, Douglas E. |edition=2018 |date=2018 |publisher=Syneca Research |isbn=978-1-387-49193-3}}</ref>{{rp|125}}

In a 1954 study (180 – Degree Turn Experiment), the University of Illinois Institute of Aviation found that 19 out of 20 non-instrument-rated subject pilots went into a graveyard spiral soon after entering simulated instrument conditions.  The 20th pilot also lost control of his aircraft, but in another maneuver. The average time between onset of instrument conditions and loss of control was 178 seconds.<ref>{{cite book| publisher=University of Illinois |first1=Leslie |last1=Aulls Bryan |last2=Stonecipher |first2=Jesse W. |last3=Aron |first3=Karl |year=1954 |asin=B0007EXGMI |title=180-degree turn experiment |url=https://archive.org/details/180degreeturnexp11brya/mode/2up|ol=207786M |lccn=a54009717 |oclc=4736008}}</ref>

{{main|Coriolis effect (perception)}}
Spatial disorientation can also affect [[instrument flight rules|instrument-rated]] pilots in certain conditions. A powerful tumbling sensation ([[Vertigo (medical)|vertigo]]) can result if the pilot moves his or her head too much during instrument flight. This is called the [[Coriolis effect (perception)|Coriolis illusion]]. Because the semicircular canals are set in three different axes of rotation, if the aviator suddenly moves their head during a rotational acceleration, one canal may abruptly start to detect an angular acceleration while another ceases, resulting in a tumbling sensation.<ref name=ATSB-SD2007/>{{rp|9}}

== Visual illusions ==
Even with good visibility, misleading visual inputs such as sloping cloud decks, unfamiliar runway grades, or false horizons can also form [[optical illusion]]s, resulting in the pilot misjudging the vertical orientation, aircraft speed or altitude, and/or distance and [[depth perception]]; these could even combine with nonvisual illusions from the vestibular and proprioceptive systems to produce an even more powerful illusion.<ref name=FAA-spatial-vis>{{cite web |url=https://www.faa.gov/pilots/safety/pilotsafetybrochures/media/SpatialD_VisIllus.pdf |title=Medical Facts for Pilots: Spatial Disorientation, Visual Illusions; safety brochure AM-400-00/1 |author=Antuñano, Melchor J. |access-date=9 February 2021 |publisher=Federal Aviation Administration}}</ref>

== Examples ==
{|class="wikitable sortable" style="text-align:center;font-size:90%;"
|+Selected list of aviation accidents attributed to spatial disorientation
|-
! Date !! Location !! style="width:15%;" | Accident/Flight !! class="unsortable" | Notes & Refs.
|-
| {{dts|1959|02|03|abbr=on}} || [[Clear Lake, Iowa]], USA || [[The Day the Music Died]]
|style="text-align:left;" | Crash of [[Beechcraft Bonanza]] that killed [[Buddy Holly]], [[Ritchie Valens]], and [[The Big Bopper|"The Big Bopper" J. P. Richardson]]; pilot was not qualified for instrumented flight but took off into deteriorating weather because the passengers were important. Forensic evidence showed the aircraft was in a steep right bank (90°), nose-down attitude at {{convert|3000|ft/min|abbr=on}} when it crashed.<ref>{{cite web |url=https://www.aopa.org/news-and-media/all-news/2009/february/01/safety-pilot-landmark-accidents-the-day-the-music-died |title=Safety Pilot Landmark Accidents: The Day the Music Died |author=Landsberg, Bruce |author-link=Bruce Landsberg |date=February 1, 2009 |publisher=Aircraft Owners and Pilots Association |access-date=11 February 2021}}</ref>
|-
| {{dts|1963|03|05|abbr=on}} || [[Camden, Tennessee]], USA || [[1963 Camden PA-24 crash]]
|style="text-align:left;" | Four deaths, including singer [[Patsy Cline]].
|-
| {{dts|1964|07|31|abbr=on}} || Brentwood, [[Nashville, Tennessee]], USA || 1964 Beechcraft Debonair crash
|style="text-align:left;" | It is believed{{according to|date=June 2020}} that singer [[Jim Reeves]] was suffering from spatial disorientation when his Beechcraft aircraft crashed in the Brentwood area of Nashville, Tennessee, during a violent thunderstorm on July 31, 1964, claiming the lives of both Reeves and his pianist Dean Manuel.
|-
| {{dts|1978|01|01|abbr=on}} || [[Arabian Sea]], near [[Chhatrapati Shivaji Maharaj International Airport|Santacruz Airport]], [[Bombay]], India || [[Air India Flight 855]]
|style="text-align:left;" |
|-
| {{dts|1978|10|21|abbr=on}} || [[Bass Strait]], Australia || [[Disappearance of Frederick Valentich]]
|style="text-align:left;" |
|-
| {{dts|1992|06|06|abbr=on}} || [[Darién Gap]], near [[Tucutí]], Panama || [[Copa Airlines Flight 201]]
|style="text-align:left;" |
|-
| {{dts|1999|07|16|abbr=on}} || [[Atlantic Ocean]], off the west coast of [[Martha's Vineyard]], Massachusetts, USA || [[John F. Kennedy Jr. plane crash]]
|style="text-align:left;" | Crash occurred during a [[night]] flight over water near [[Martha's Vineyard]]. Subsequent investigation pointed to spatial disorientation as a probable cause of the accident.<ref>{{cite report |url=https://www.ntsb.gov/about/employment/_layouts/ntsb.aviation/brief2.aspx?ev_id=20001212X19354&ntsbno=NYC99MA178&akey=1 |title=NTSB Identification: NYC99MA178 |date= |publisher=National Transportation Safety Board |access-date=11 February 2021}}</ref> Because of pilot [[John F. Kennedy Jr.]]'s fame, the cause of the crash led to extensive reporting of spatial disorientation in the press in 1999.<ref name="auto"/>
|-
| {{dts|2000|01|10|abbr=on}} || [[Niederhasli]], Switzerland || [[Crossair Flight 498]]
|style="text-align:left;" |
|-
| {{dts|2000|08|23|abbr=on}} || [[Persian Gulf]], near [[Bahrain International Airport]], Bahrain || [[Gulf Air Flight 072]]
|style="text-align:left;" |
|-
| {{dts|2000|10|16|abbr=on}} || [[Hillsboro, Missouri]], USA || 2000 Cessna 335 crash
|style="text-align:left;" | Left-side attitude indicator failed and pilot kept turning his head to cross-check the right-side (co-pilot position) attitude indicator, leading to spatial disorientation;<ref>{{cite report |url=https://www.ntsb.gov/investigations/AccidentReports/Reports/AAB0202.pdf |title=Aircraft Accident Brief AAB-02/02, Accident Number CHI01MA011 |date=2002 |publisher=National Transportation Safety Board |access-date=28 February 2021}}</ref> the crash killed Missouri Governor [[Mel Carnahan]].<ref>{{cite news |url=https://www.aopa.org/news-and-media/all-news/2002/june/06/spatial-disorientation-doomed-carnahan-flight |title=Spatial disorientation doomed Carnahan flight |date=June 6, 2002 |publisher=Aircraft Owners & Pilots Association |access-date=28 February 2021}}</ref>
|-
| {{dts|2004|01|03|abbr=on}} || [[Red Sea]], near [[Sharm El Sheikh International Airport]], Egypt || [[Flash Airlines Flight 604]]
|style="text-align:left;" | Disputed cause: possible pilot error (from spatial disorientation) or mechanical/software malfunctions
|-
| {{dts|2005|03|15|abbr=on}} || near Campbeltown, Argyll, Scotland || [[2005 Loganair Islander accident]]
|style="text-align:left;" |
|-
| {{dts|2007|01|01|abbr=on}} || [[Makassar Strait]] off [[Majene]], [[Sulawesi]], Indonesia || [[Adam Air Flight 574]]
|style="text-align:left;" |Due to the crew's focus on troubleshooting a problem with the [[Inertial navigation system|INS]], they had disconnected the autopilot without noticing and did not realize that they were in a descent until recovery was improbable. The [[G-force|G forces]] on the aircraft were stressing the hull of the aircraft and further disoriented the crew until the aircraft broke up in mid-air.
|-
| {{dts|2007|05|05|abbr=on}} || [[Douala International Airport]], Cameroon || [[Kenya Airways Flight 507]]
|style="text-align:left;" |
|-
| {{dts|2007|11|30|abbr=on}} || Türbetepe, [[Keçiborlu]], [[Isparta Province]], Turkey || [[Atlasjet Flight 4203]]
|style="text-align:left;" |
|-
| {{dts|2008|09|14|abbr=on}} || [[Perm, Russia]] || [[Aeroflot Flight 821]]
|style="text-align:left;" |
|-
| {{dts|2009|06|01|abbr=on}} || over [[Atlantic Ocean]], near waypoint TASIL || [[Air France Flight 447]]
|style="text-align:left;" |
|-
| {{dts|2010|05|12|abbr=on}} || [[Tripoli International Airport]], Libya || [[Afriqiyah Airways Flight 771]]
|style="text-align:left;" |
|-
| {{dts|2010|08|24|abbr=on}} || near [[Shikharpur, Narayani|Shikharpur]], Nepal || [[Agni Air Flight 101]]
|style="text-align:left;" |
|-
| {{dts|2012|10|01|abbr=on}} || Upper Kandanga, [[Queensland]], Australia || [[2012 Queensland DH.84 Dragon crash]]
|style="text-align:left;" | Vintage aircraft named ''Riama''
|-
|Mar 19, 2016
|[[Rostov-on-Don]], Russia
|[[Flydubai Flight 981]]
|
|-
| {{dts|2018|05|12|abbr=on}} || near [[Centennial Airport]], Colorado, USA || Cirrus SR22 crash
|style="text-align:left;" | Federal investigators determined that pilot disorientation in difficult weather conditions likely was the cause of a fatal small plane crash.<ref>{{Cite web|url=https://coloradosun.com/2019/11/12/robert-marquis-plane-crash-centennial-airport-colorado/|title = Pilot disorientation caused deadly crash near Centennial Airport that left engine lodged in home, NTSB rules|date = 31 May 2023}}</ref><ref>{{Cite web|url=https://sentinelcolorado.com/metro/pilot-disorientation-blamed-in-fatal-crash-near-denver/|title = Pilot disorientation blamed in fatal crash after leaving Centennial Airport|date = 31 May 2023}}</ref>
|-
| {{dts|2019|02|23|abbr=on}} || [[Trinity Bay (Texas)|Trinity Bay]], [[Texas]], USA || [[Atlas Air Flight 3591]]
|style="text-align:left;" | The crash of the [[Boeing 767]] cargo jet was caused by the inappropriate response by the first officer as the pilot flying to an inadvertent activation of the plane's go-around mode at a high altitude (6,200 feet), which led to his spatial disorientation.<ref>{{Cite web|url=https://www.aircargonews.net/airlines/freighter-operator/ntsb-releases-atlas-air-freighter-crash-findings/|title = NTSB releases Atlas Air freighter crash findings|date = 15 July 2020}}</ref><ref>{{Cite web|url=https://www.ntsb.gov/investigations/pages/DCA19MA086.aspx|title=DCA19MA086.aspx}}</ref>
|-
| {{dts|2019|04|09|abbr=on}} || near [[Aomori Prefecture]], Japan || 2019 JASDF F-35 crash
|style="text-align:left;" | First crash of an [[F-35]]A;<ref>{{cite news |url=https://www.japantimes.co.jp/news/2019/06/07/national/remains-japan-asdf-pilot-found-two-months-f-35a-fighter-crash-off-aomori/ |title=Remains of Japan ASDF pilot found, two months after F-35A fighter crash off Aomori |date=June 7, 2019 |work=The Japan Times |access-date=11 February 2021}}</ref> pilot descended rapidly during a simultaneous left-hand turn.<ref>{{cite news |url=https://www.defensenews.com/global/asia-pacific/2019/06/10/japan-blames-spatial-disorientation-for-f-35-crash/ |title=Japan blames spatial disorientation for F-35 crash |author=Yeo, Mike |date=June 10, 2019 |work=Defense News |access-date=11 February 2021}}</ref><ref>{{Cite news|url=https://www.bbc.com/news/world-asia-48578178 |title=Japan pilot crashed after 'spatial disorientation' |work=BBC News |date=2019-06-10 |access-date=2019-06-10|language=en-GB}}</ref>
|-
| {{dts|2020|01|26|abbr=on}} || [[Calabasas, California]], USA || [[2020 Calabasas helicopter crash]]
|style="text-align:left;" | Ara Zobayan, the helicopter pilot in the [[2020 Calabasas helicopter crash|fatal accident]] that killed [[Kobe Bryant]] along with his daughter [[Gianna Bryant|Gianna]] and six others on January 26, 2020, was determined to have likely experienced spatial disorientation according to NTSB investigation.<ref>{{Cite news|url= https://www.nba.com/news/investigators-report-bryants-pilot-got-disoriented-in-clouds |title=Investigators report Kobe Bryant's pilot got disoriented in clouds|date=2021-02-09|access-date=2021-02-10}}</ref>
|}

== See also ==
* {{annotated link|Balance disorder}}
* {{annotated link|Bárány chair}}
* {{annotated link|Broken escalator phenomenon}}
* {{annotated link|Brownout (aeronautics)}}
* {{annotated link|Dizziness}}
* {{annotated link|Sense of balance|Equilibrioception}}
* {{annotated link|Ideomotor phenomenon}}
* {{annotated link|Illusions of self-motion}}
* {{annotated link|Motion sickness}}
* {{annotated link|Pilot error}}
* {{annotated link|Proprioception}}
* [[Sense of direction]]
* {{annotated link|Sensory illusions in aviation}}
* {{annotated link|Situation awareness}}
* [[Spatial ability]]
* [[Topographical disorientation]]

== References ==
{{Reflist}}

== External links ==
* {{cite web|url=http://www.graybiel.brandeis.edu/history/history.html|title=Ashton Graybiel Spatial Orientation Laboratory – Brandeis University|access-date=30 July 2016}}

[[Category:Aviation risks]]
[[Category:Vision]]
[[Category:Proprioception]]