VISUAL ILLUSIONS

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VISUAL ILLUSIONS

• SSG RODRIGUEZ
• REFERENCES
• FM 1-301, TC 1-204

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VISUAL ILLUSIONS

• The purpose of this class is to give aircrew
  members the understanding of the illusions and
  disorientation that can be experienced while
  flying.
• Even with references outside the cockpit and the
  display of instruments inside, aircrew members
  must be aware and interpret information correctly.

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VISUAL ILLUSIONS

• Decreasing visual information increases the
  provability of spatial disorientation. Reduced
  visual reference also create several illusions
  that can induce spatial disorientation.
• The acronym that will help you remember the
  visual illusions is
• F.F.F. C.R.A.S.H. S.A.R.

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VISUAL ILLUSIONS

• FASCINATION (FIXATION) Occurs when crew ignore
  orientation cues and focus their attention on
  their object and goals. Target hypnosis is a
  common type of fascination. When a pilot intents
  to hit a target during gunnery run, the pilot may
  delay pull-up so long that the aircraft may hit
  the ground.
• Increasing scanning techniques will help avoid
  this illusion.

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VISUAL ILLUSIONS

• FLICKER VERTIGO A light flickering at a rate of
  4 to 20 cycles per sec. Nausea and vomiting in
  mild cases will occur. In severe cases
  convulsions and unconsciousness can be
  experienced. Fatigue, frustration and boredom
  tent to add to this problem. During the day, the
  sunlight flickering through the rotor blades will
  create this effect. During the night,
  anti-collision lights reflecting against overcast
  sky, haze, or the rotor system.
• Proper scanning techniques will decrease focusing
  on the flickering.

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VISUAL ILLUSIONS

• FALSE HORIZON Cloud formations may be confused
  with the horizon on the ground. Confusion may
  result when a crewmember looks up after being
  focused inside the cockpit for an extended period
  of time. Outside references for attitude are less
  obvious and reliable at night.
• Pilots should cross reference with instruments.

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VISUAL ILLUSIONS

• CONFUSION WITH GROUND LIGHTS At night, pilots
  can put the aircraft in very unusual attitudes to
  keep ground lights above them. They can mistake
  the ground lights for the horizon and seashore
  lights with stars. This cause the pilots to
  maneuver close to the sea or ground.
• Cross reference with instruments will help this
  illusion.

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VISUAL ILLUSIONS

• REVERSIBLE PERSPECTIVE At night, an aircraft
  may appear to be going away when is actually
  approaching. This occurs when one aircraft is
  flying parallel to another.
• Watch for the lights, if the are increasing in
  size the aircraft is coming at you and if they
  are decreasing is going away from you. A key to
  remember is If the red position light is on the
  RIGHT, the aircraft is RETURNING. RED, RIGHT,
  RETURN.

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VISUAL ILLUSIONS

• AUTOKINESIS When you stare at a static light in
  the dark, the light appears to move. If you take
  a lighted cigarette in a dark room, movement will
  begin in about 8 to 10 seconds. Your eyes are
  trying to find another visual reference point.
  This illusion is not limited to the darkness, it
  can happen at any time.
• Correct scanning is the most important solution
  to this problem. You should not stare at any
  object or light for more than 10 seconds.

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VISUAL ILLUSIONS

• SIZE-DISTANCE ILLUSION This results from viewing
  a light that increases and decreases in
  brightness. At night, an aircraft hovers next to
  your aircraft and turns the lights from dim to
  bright. The aircraft will appear to jump closer
  to you when it is in the same position.
• Awareness of the aircrafts position and proper
  scanning techniques will help you to determine if
  the aircraft is in fact moving closer to you.

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VISUAL ILLUSIONS

• HEIGHT PERCEPTION ILLUSION It is the feeling of
  being higher above the terrain than you really
  are. The lack of visual references in areas of
  poor contrast such as snow, water, or the desert
  will give you this illusion.
• Monitor the shadow cast by near objects, such as
  landing gear, or the aircraft shadow at a hover.

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VISUAL ILLUSIONS

• STRUCTURAL ILLUSION Caused by things that
  obscure the vision such as rain showers, heat
  waves, snow, or sleet.
• A straight line may appear to be curved when
  viewed in a desert heat wave, or through a
  bubble window.
• Be aware of the illusion and your surroundings
  and change the perspective of view to determine
  the object that you are trying to identify.

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VISUAL ILLUSIONS

• ALTERED PLAINS OF REFERENCE A sense of feeling
  that the pilot needs to climb when the altitude
  is adequate for crossing an obstacle.
• When flying over mountains, the pilots may feel
  the need to climb in altitude when they are well
  cleared of the mountains.
• Cross reference with the altimeters and altimeter
  settings and knowing the altitude of the object
  will help with this illusion.

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VISUAL ILLUSIONS

• RELATIVE MOTION This illusion is often
  encountered during a formation flight when pilots
  see the movement of other aircraft in their
  peripheral vision and interpret it as their own
  motion. Hovering over high grassy areas and
  focusing on the movement of the grass will give
  them a sense of aircraft movement.
• Proper scanning and use of reference points to
  include the members on the back calling the
  drifting of the aircraft will help with this
  illusion.

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VISUAL ILLUSIONS

• In conclusion, this class will give you the
  fundamental understanding of this illusions. It
  will take time and careful reviewing of your
  notes and books to get a full grasp of this
  illusions. You should review this at least once a
  week or before a day or night flight.
• Be aware of this illusions and recognize them as
  soon as they appear. If you need help, ask
  another crewmember to clarify what you are
  seeing. Always call it as you see it!

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QUESTIONS????