CH.I.I.K5

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• Helicopter Flying Handbookp. 12-4
  Chapter 12: Night Operations › Night Vision › Night Scanning

  Night Vision Diet and general physical health have an impact on how well a person can see in the dark. Deficiencies in vitamins A and C have been shown to reduce night acuity. Other factors, such as carbon monoxide poisoning ... smoking, alcohol, and certain drugs can greatly decrease night vision. Lack of oxygen can also decrease night vision as the eye requires more oxygen per unit weight than any other part of the body. Night Scanning Good night visual acuity…

• Pilot's Handbook of Aeronautical Knowledgep. 17-22
  Chapter 17: Aeromedical Factors › Vision in Flight › Night Blind Spot

  Night Vision There are many good reasons to fly at night, but pilots must keep in mind that the risks of night flying are different than during the day and often times higher. [Figure 17-16] Pilots who are cautious ... educated on night-flying techniques can mitigate those risks and become very comfortable and proficient in the task. Night Blind Spot It is estimated that once fully adapted to darkness, the rods are 10,000 times more sensitive to light…

• Pilot's Handbook of Aeronautical Knowledgep. 17-24
  Chapter 17: Aeromedical Factors › Vision in Flight › Night Vision Protection

  This precaution increases the rate of dark adaptation at night and improves night visual sensitivity. Oxygen Supply Unaided night vision depends on optimum function and sensitivity of the rods of the retina. Lack of oxygen to the rods (hypoxia) significantly ... reduces their sensitivity. Sharp clear vision (with the best being equal to 20–20 vision) requires significant oxygen especially at night. Without supplemental oxygen, an individual’s night vision declines measurably at pressure altitudes above 4,000 feet. As altitude…

• Pilot's Handbook of Aeronautical Knowledgep. 17-23
  Chapter 17: Aeromedical Factors › Vision in Flight › Scanning Techniques

  Figure 17-18. Scanning techniques. Off-center viewing is another type of scan that pilots can use during night flying. It is a technique that requires an object be viewed by looking 10° above, below, or to either side ... object. [Figure 17-19] In this manner, the peripheral vision can maintain contact with an object. With off-center vision, the images of an object viewed longer than 2 to 3 seconds will disappear. This occurs because the rods reach…

• Helicopter Flying Handbookp. 12-2
  Chapter 12: Night Operations › Visual Deficiencies › Night Myopia

  Visual Deficiencies Night Myopia At night, blue wavelengths of light prevail in the visible portion of the spectrum. Therefore, slightly nearsighted (myopic) individuals viewing blue-green light at night may experience blurred vision. Even pilots with perfect vision find that ... image sharpness decreases as pupil diameter increases. For individuals with mild refractive errors, these factors combine to make vision unacceptably blurred unless they wear corrective glasses. Another factor to consider is “dark focus.” When light levels decrease, the focusing mechanism…

• 14 CFR Part 61 — Certification: Pilots, Flight Instructors, and Ground InstructorsOpen
  14 CFR § 61.57 Recent flight experience: Pilot in command.

  section do not apply to the examiner or the applicant during a practical test required by this part. (f) Night vision goggle operating experience. (1) A person may act as pilot in command in a night vision goggle operation with ... person performs and logs the following tasks as the sole manipulator of the controls on a flight during a night vision goggle operation— (i) Three takeoffs and three landings, with each takeoff and landing including a climbout, cruise, descent…