CFI Instrument Practical Test Standards, FAA-S-8081-9B, June 2001

II. Technical Subject Areas

B. Aeromedical Factors

    1. Hypoxia
      a. Oxygen deficiency of body enough to impair brain and other organ function
      b. High altitude hypoxia is due to reduced barometric pressure
      c. Signs and symtoms related to cabin pressure altitude
        1) 5,000 feet: deterioration in night vision
        2) 12,000 to 15,000 feet: impairment of judgment, memory, alertness, coordination and ability to make calculations, plus headache, drowsiness, dizziness and either euphoria or belligerence
        3) 15,000 feet: performance can seriously deteriorate in 15 minutes
        4) Above 15,000 feet: tunnel vision, cyanosis
        5) 18,000 feet: ability to take corrective action lost in 20-30 minutes
        6) 20,000 feet: ability to take corrective action lost in 5-12 minutes, followed by unconsciousness
      d. Factors that lower altitude at which significant effects of hypoxia may occur (increase susceptibility to hypoxia)
        1) Carbon monoxide
        2) Anemia
        3) Medications/drugs
          a) Alcohol
          b) Antihistamines
          c) Sedatives, tranquilizers
          d) Analgesics
        4) Extreme cold, heat or fever
        5) Anxiety
      e. Ability to recognize hypoxia can be improved by experiencing simulatied flight in an altitude chamber, provided by the FAA (FAA Airman Education Programs Branch (AAM-420), Civil Aeromedical Institute, Mike Monroney Aeronautical Center, Post Office Box 25082, Oklahoma City, Oklahoma 73125; telephone 405-954-6212)
      f. Preventive measures
        1) Refrain from alcohol, and do not smoke prior to flight
        2) Use only medications prescribed by a fight surgeon or aviation medical examiner
        3) Do not fly above 10,000 feet without supplemental oxygen on board
        4) Use supplemental oxygen at higher altitudes
          a) 14 CFR 91.211
            i) Pilots of unpressurized aircraft use supplemental oxygen when flying higher than 12,500 feet MSL for 30 minutes or more and at all times above 14,000 feet MSL
            ii) Every aircraft occupant must be provided supplemental oxygen above 15,000 feet MSL
          b) Use of supplemental oxygen is recommended (AIM 8-1-2) above
            i) 10,000 feet during the day
            ii) 5,000 feet at night
    Instrument Flying Handbook, FAA-H-8083-15, 1999
    AIM 8-1-2

Greg Gordon MD, CFII