Unit 9 Asma Spatial Orientation And Situational Awareness

Front 1

State the potential disorientation factors associated with empty field myopia

Back 1

Empty-field Myopia is a condition that occurs when flying on hazy days. The haze provides nothing specific to focus on and this causes the eye to focus 10 to 30 feet in front of your aircraft. So while you are looking, you are not seeing. An effective scan will help you avoid Empty-field Myopia. Look out in front of the aircraft and focus on something on the ground, then raise your eyes up to and above the horizon. This will force your eyes to focus beyond the 10-to-30 foot distance.

Front 2

State the potential disorientation factors associated with terrain size constancy

Back 2

Size constancy is very important in judging distance, and false cues are often responsible for aircraft mishaps resulting from illusions of focal visual origin. If the terrain descends to the approach end of the runway, the pilot tends to fly a steeper approach than he or she would if the approach terrain were level. If the approach terrain slopes up to the runway, on the other hand the pilot tends to fly a less steep approach than he or she would otherwise.

Front 3

State the potential disorientation factors associated with runway landing illusions

Back 3

A runway that is narrower than the pilot is accustomed can create a hazardous illusion on the approach to landing. Size constancy causes the pilot to perceive the narrow runway to be farther away (i.e. that the a/c is higher) than is actually the case, and the pilot may flare too late and touch down sooner than expected. Likewise, a runway that is wider than what a pilot is used to can lead to the illusion of being closer to the runway (i.e. lower) than reality, and the pilot may flare too soon and drop in from too high above the runway.

Front 4

State the potential disorientation factors associated with absent focal cues

Back 4

A well-known pair of approach to landing situations that create illusions because of the absence of adequate focal visual orientation cues are the smooth water (glassy water) and snow covered approach. A seaplane pilots perception of height is degraded substantially when the water below is still. For that reason, a pilot routinely sets up a safe descent rate and waits for the seaplane to touch down, rather than attempting to flare to a landing when the water is smooth. A blanket of fresh snow on the ground and runway also deprives the pilot of visual cues with which to estimate height, thus making the approach extremely difficult.

Front 5

State the potential disorientation factors associated with the whiteout approach

Back 5

An approach made under whiteout conditions can be as difficult as a black-hole approach. Lack of sufficient ambient visual orientation cues. Without peripheral visual cues to help provide orientation relative to the Earth, the pilot tends to feel that the aircraft is stable and situated appropriately but that the runway itself moves about or remains malpositioned.

Front 6

State the potential disorientation factors associated with autokinesis

Back 6

One puzzling illusion that occurs when ambient visual orientation cues are minimal is visual autokinesis. A small dim light seen against a dark background is an ideal stimulus for producing autokinesis. After 6-12 sec of visually fixating the light, one can observe it to move at up to 20 degrees/sec in a particular direction or in several directions in succession, but there is little apparent displacement of the object fixated. In general, the larger and brighter the object, the less the autokinetic effect. A small, solitary light or small group of lights seen in the dark can appear to move, when in fact they are stationary

Front 7

State the potential disorientation factors associated with optical flow

Back 7

The optical flow field appears to expand from a focal point, which indicates the direction of motion. For curved motion the expanding flow field tends to bend sideways, and the focal point is no longer defined. Grunwald et al (1991) have shown how parasitic image shifts, due to lags in a flight simulator with a head-coupled head-mounted display, distort the visual flow field. In straight and level flight, the parasitic image motions which occur during head movements will cause the expanding visual pattern to appear to bend, creating the illusion of a curved flight path. The bending effect is proportional to the ratio between the magnitude of the image shifts and the apparent velocity along the line of sight. The apparent velocity depends on the velocity to height ratio. Hence the angular errors induced by the bending effect increase with decreased velocity and increased altitude.

Front 8

Define vection

Back 8

Vection is the visually induced perception of self-motion in the spatial environment and can be a sensation of linear or angular motion. (I.e. the adjacent vehicle seen moving aft in the peripheral vision causes the subject to feel as though moving forward.) DH 210

Front 9

Define circular vection

Back 9

Illusions of self-rotation, caused by rotating scenes, are referred to as circular vection.

Front 10

Define linear vection

Back 10

Illusions of translational self-motion, caused by scenes moving in a flat plane, are referred to as linear vection.

Front 11

State the potential disorientation factors associated with linear vection

Back 11

In the absence of head motions, illusions of self-motion can be produced by moving images on a display. Illusions of self-motion can also be induced by somatosensory mechanisms, such as when walking in the dark, on a rotating platform, in the opposite direction to the platform motion

Front 12

What happens when both visual and vestibular motion cues are both present?

Back 12

When visual and vestibular motion cues are both present, there is an important non-linear interaction whereby rapidly occurring conflicts between visual and vestibular cues, especially those involving direction disparities, result in a precipitous decline in visually-induced vection and a temporary domination by the vestibular response.

Front 13

What does Zacharias and Young suggest that rotational self-motion is estimated by?

Back 13

That rotational self-motion is estimated by combining complementary visual and vestibular cues: low frequency visual cues are used to augment high frequency vestibular cues giving the capability of sensing head motion over a wide range of frequencies.

Front 14

State the potential disorientation factors associated with angular vection

Back 14

Vection is the visually induced perception of self-motion in the spatial environment and can be a sensation of linear or angular motion. (i.e. objects seen revolving around the subject in the flight simulator leads to a sense of self-rotation in the opposite direction)

Front 15

State the potential disorientation factors associated with concentric vection

Back 15

Vection is a visually induced perception of self-motion in the spatial environment and can be sensation of linear motion (linear vection) and angular motion (angular vection). (i.e. linear vection…the adjacent vehicle seen moving aft in the peripheral vision causes the subject to feel as though moving forward.)

Front 16

State the potential disorientation factors associated with false horizons

Back 16

Often the horizon perceived through ambient vision is not really horizontal. Quite naturally, this misperception of the horizontal creates hazards in flight. A sloping cloud deck, for example, is very difficult to perceive as anything but horizontal if it extends fro any great distance into the pilot’s peripheral vision.

Front 17

Define the black hole illusion

Back 17

A black-hole illusion involves approaching a runway under conditions with no lights before the runway and with city lights or rising terrain beyond the runway.

Front 18

When can a black hole illusion happen?

Back 18

A Black-Hole Approach Illusion can happen during a final approach at night (no stars or moonlight) over water or unlighted terrain to a lighted runway beyond which the horizon is not visible. In the example when peripheral visual cues are not available to help you orient yourself relative to the earth, you may have the illusion of being upright and may perceive the runway to be tilted left and upsloping. However, with the horizon visible you can easily orient yourself correctly using your central vision.
Black-hole illusion involves approaching a runway under conditions with no lights before the runway and with city lights or rising terrain beyond the runway.

Front 19

A particularly hazardous black hole illusion involves what?

Back 19

A particularly hazardous black-hole illusion involves approaching a runway under conditions with no lights before the runway and with city lights or rising terrain beyond the runway. These conditions may produce the visual illusion of a high-altitude final approach. If you believe this illusion, you may respond by lowering your approach slope.

Front 20

State the potential disorientation factors associated with the perspective illusion

Back 20

This illusion may make a pilot change (increase or decrease) the slope of his or her final approach. They are caused by runways with different widths, upsloping or downsloping runways, and upsloping or downsloping final approach terrain. Pilots learn to recognize a normal final approach by developing and recalling a mental image of the expected relationship between the length and the width of an average runway.

Front 21

What illusion do you get with an upsloping runway?

Back 21

Upsloping runway: A final approach over a flat terrain with an upsloping runway may produce the visual illusion of a high-altitude final approach. If you believe this illusion, you may respond by pitching the aircraft nose down to decrease the altitude, which, if performed too close to the ground, may result in an accident.

Front 22

What illusion do you get with a downsloping runway?

Back 22

Downsloping runway: A final approach over a flat terrain with a downsloping runway may produce the visual illusion of a low-altitude final approach. If you believe this illusion, you may respond by pitching the aircraft nose up to increase the altitude, which may result in a low-altitude stall or a missed approach.

Front 23

What illusion do you get with upsloping terrain

Back 23

Upsloping terrain: A final approach over an upsloping terrain with a flat runway may produce the visual illusion of a high-altitude final approach. If you believe this illusion, you may respond by pitching the aircraft nose down to decrease the altitude, which, if performed too close to the ground, may result in an accident.

Front 24

What illusion do you get with downsloping terrain

Back 24

Downsloping: A final approach over a downsloping terrain with a flat runway may produce the visual illusion of a low-altitude final approach. If you believe this illusion, you may respond by pitching the aircraft nose up to increase the altitude, which may result in a low-altitude stall or a missed approach.

Front 25

What illusion do you get with a narrow runway?

Back 25

Narrow runway: A final approach to an unusually narrow runway or an unusually long runway may produce the visual illusion of a high-altitude final approach. If you believe this illusion, you may respond by pitching the aircraft nose down to decrease the altitude, which, if performed too close to the ground may result in an accident.

Front 26

What illusion do you get with a wide runway?

Back 26

Wide runway: A final approach to an unusually wide runway may produce the visual illusion of a low-altitude final approach. If you believe this illusion, you may respond by pitching the aircraft nose up to increase the altitude, which may result in a low-altitude stall or a missed approach.

Front 27

State the potential disorientation factors associated with oculogyral illusions

Back 27

Is a false sensation of motion of an object viewed by such a subject. For example, if a vehicle with a subject inside is rotating about a vertical axis at a constant velocity and suddenly stops rotating, the subject experiences not only a somatogyral illusion of rotation in the opposite direction, but also an oculogyral illusion of an object in front of them moving in the opposite direction.

Front 28

State the potential disorientation factors associated with coriolis cross-coupling

Back 28

This is a false percept that results from stimulation of the semicircular canals by moving different canals into and out of the plane of motion during constant angular velocity. This is considered to be a cross coupled stimulation of the semicircular canals and it causes a sensation of movement in the direction of the constant angular velocity

Front 29

State the potential disorientation factors associated with somatogyral illusions

Back 29

False sensation or lack of sensation of self rotation in a subject undergoing unusual angular motion…. somatogyral illusions result from the inability of the semicircular canal to accurately register prolonged rotation (sustained angular velocity). Technically, it is the sensation of turning in the opposite direction that occurs during deceleration after a period of sustained angular velocity

Front 30

State the potential disorientation factors associated with somatogravic illusions

Back 30

Somatogravic illusions are caused by linear accelerations. These illusions involving the utricle and the saccule of the vestibular system are most likely under conditions with unreliable or unavailable external visual references

Front 31

State the potential disorientation factors associated with the inversion illusion

Back 31

The inversion illusion involves a steep ascent (forward linear acceleration) in a high-performance aircraft, followed by a sudden return to level flight. When the pilot levels off, the aircraft speed is relatively higher. This combination of accelerations produces an illusion that the aircraft is in inverted flight. The pilots response to this illusion is to lower the nose of the aircraft.

Front 32

What is the head-up illusion?

Back 32

The head-up illusion involves a sudden forward linear acceleration during level flight where the pilot perceives the illusion that the nose of the aircraft is pitching up. The pilot's response to this illusion would be to push the yoke or the stick forward to pitch the nose of the aircraft down. A night take-off from a well-lit airport into a totally dark sky (black hole) or a catapult take-off from an aircraft carrier can also lead to this illusion, and could result in a crash.

Front 33

What is the head-down illusion?

Back 33

The head-down illusion involves a sudden linear deceleration (air braking, lowering flaps, decreasing engine power) during level flight where the pilot perceives the illusion that the nose of the aircraft is pitching down. The pilot's response to this illusion would be to pitch the nose of the aircraft up. If this illusion occurs during a low-speed final approach, the pilot could stall the aircraft.

Front 34

State the potential disorientation factors associated with the G-excess illustion

Back 34

The G-excess illusion is another type of somatogravic illusion that results from the otolithic membrane displacement under G-Forces. Typically, the G-Excess illusion occurs in jets during a turn and head movement and causes uncommanded tilt in both pitch and roll The G-excess illusion during a turn in flight. G-induced excessive movement of the pilot’s otolithic membranes causes the pilot to feel an extra amount of head and body tilt, which is interpreted as an underbank of the aircraft when the pilot looks up to the inside of the turn. Correcting for the illusion, the pilot overbanks the aircraft and it descends