II. Task I: High Altitude Operations
Where do you find information on supplemental oxygen requirements? What does the regulation say?
91.211 Supplemental Oxygen 1) 12500-14000: minimum flight crew is provided with oxygen on flights more than 30 min. 2) 14000-15000: Required crew members must use supplemental oxygen 3) 15000+: each occupant must be provided with supplemental oxygen. For Pressurized aircraft: 1) at least a 10-min O2 supply available for each occupant 2) one pilot must be wearing a secured and sealed mask. Exception: not n/a below FL250 if two pilots are at controls and both have quick donning masks - can be put on (secured and sealed) with one hand within 5 seconds. This means if one pilot leaves controls for any reason, the other pilot needs to put on the mask.
What is a cannula?
A canulla is an ergonomic piece of plastic tubing that runs under the nose to administer oxygen to the user. Canullas are typically more comfortable than masks, but may not provide an adequate flow of oxygen as reliably as masks when operating at higher altitudes.
Why do we use aviator's oxygen instead of medical?
Aviator's oxygen is 99.5% O2, so freezing doesn't occur at high altitudes. Medical oxygen has too much water in it so it'd freeze.
What are the three types of supplemental oxygen systems?
Diluter-Demand: Supply oxygen only when the user inhales through the mask. The mask provides a tight seal over the face to prevent dilution up to 40,000'. Pressure-Demand: Similar to diluter-demand, except that oxygen is supplied to the mask under pressure at cabin altitudes above 34,000'. Pressure-demand regulators create airtight and oxygen-tight seals, but they also provide a positive pressure application of oxygen to the mask face piece that allows the user's lungs to be pressurized with oxygen. Continuous-Flow: usually provided for passengers. The passenger mask typically has a reservoir bag that collects oxygen from the continuous-flow oxygen system during the time when the mask user is exhaling.
What is rapid decompression? Explosive? How do you recover from decompression?
During a rapid decompression, there may be a noise, and the cabin can fill with fog (from the rapid decrease in temperature), dust, or flying debris. Ears may pressurize and it by be difficult to catch your breath. The primary danger is hypoxia if supplemental oxygen is not administered immediately In an explosive decompression, the change of cabin pressure occurs faster than the lungs can decompress (<0.5 seconds) Recovery from all decompressions is similar and includes donning oxygen masks and making an emergency descent (mask first to prevent loss of consciousness)
What is a physiological hazard associated with high altitudes?
Hypoxia (Hypoxic, Stagnant, Hypemic, Histotoxic)
How does a pressurization system work?
In a typical pressurization system, the cabin, flight compartment, and baggage compartments are incorporated into a sealed unit capable of containing air under a pressure higher than outside atmospheric pressure. On aircraft powered by turbine engines, bleed air from the engine compressor section is used to pressurize the cabin.
How must aviators care and store portable oxygen? How often should the O2 container be inspected, and what mnemonic is used?
O2 is stored inside a portable O2 container. O2 is flammable so be careful. Cans should be inspected regularly. Inspection - must be inspected EVERY FLIGHT (use PRICE acronym) PRICE - checklist Pressure - in proper range Regulator - verify it is working Indicator - very it is moving/indicating properly Connected properly Emergency - ready to use in case of emergency
Whats an analogy to use for the pressurization? What is cabin pressure usually set to? Give a summary of the pressurization system.
Pressurized aircraft are sort of like a soda can. The pressure on this inside is different than on the outside. We want the cabin pressure in aircraft to 8,000' pressure. Some newer plans get it down to 6,000'. Air comes in through engines to pressurize the cabin, there is an outflow valve and a safety dump valve to ensure safe pressures are maintained and they do not get too low or high.
