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High Altitude Operations

Objective​

To understand the physiology, equipment, and regulations regarding high altitude flights, including pressurization and oxygen systems.

Motivation​

High altitude flight presents unique risks and challenges that must be mitigated through various equipment requirements. A commercial pilot preparing to fly at high altitudes needs to understand the equipment and human factors involved.

Timing​

45 minutes

Format​

Elements​

  • Altitude and air density
    • Hypoxia
    • Time of useful consciousness
    • Supplement oxygen
  • Regulations
    • 91.211(a): Minimum oxygen requirements
    • 91.211(b): Pressurize aircraft oxygen requirements
  • Supplement oxygen systems
    • Continuous flow systems
      • Constant flow
      • Adjustable flow
      • Altitude-compensated flow
    • Oxygen masks
      • Oronasal rebreather: Bag
      • Cannula
    • Electrical pulse-demand systems
    • Higher-altitude systems
      • Diluter-demand: Mask with tight seal
        • Generally good up to 40,000'
      • Pressure-demand
        • Allows for pressures above 40,000'
  • Pulse oximeters
    • >90 is good
  • Pressurization
    • Principle of operation
    • Components of a pressurization system
      • Airtightness
      • Compressed air delivery
      • Controller to regular pressure
      • Safety dump valve
    • Turbo-charged pressurized aircraft
      • Regulator operation
      • Outflow valve
      • Dump valve
    • Cabin instrumentation
    • Decompression
      • Slow decompression: < 10 sec
      • Rapid decompression: Lungs decompress faster than cabin
      • Explosive decompression: Cabin loses pressure faster than lungs can decompression (.2-.5s)
        • Lung damage
        • Hypoxia
        • Loss of consciousness
        • Decompression sickness
        • Fog, debris, noise

References​