Oxygen & Pressurization

• Storage System
• Delivery System
• Mask or Cannula

Continuous Flow

• Placed over face, does not seal (wasteful), usually for passengers
• Used up to 28,000’ MSL

Diluter-Demand

• Supplies oxygen only when the user inhales through the mask
• Provides a tight seal over entire face (facial hair will interfere)
• Regulator allows mixing of cabin air and oxygen, or one-hundred percent oxygen, depending on altitude
• Used up to 40,000’ MSL

Pressure-Demand

• Air-tight seal over face, used when one-hundred percent oxygen is not sufficient
• Above 34,000’ MSL, mask provides positive pressure application of oxygen, and allows the user’s lungs to be pressurized (to a lower altitude)
• Regulator may be attached to mask or mounted on the flight deck (long hoses must be purged)
• Used above 40,000’ MSL

Electrical Pulse-Demand

• Detects an inhalation effort and provides oxygen flow during the initial portion of inhalation
• Does not waste oxygen (provided only during the breathing cycle)
• Can reduce the amount of oxygen needed by 50-85 percent compared to continuous flow
• May use internal barometer that compensates for increasing altitude by increasing oxygen delivered for each pulse

Nasal Cannula

• Plastic tubing that runs under nose
• Not as reliable as oxygen masks
• Continuous flow, meter must be checked periodically
• Not permitted above 18,000’ MSL (mask is required)

Oral-Nasal Rebreather

• Reservoir bag collects exhaled air, then mixes it with one-hundred percent oxygen
• Used up to 25,000’ MSL

Airline Drop-Down Units

• Also called ‘phase-dilution’, ‘phase-sequential’, or ‘dixie cup’
• Continuous flow, external reservoir bag collects one-hundred percent oxygen
• User to inhales until the bag has emptied, and a series of one-way valves allows the user to continue to inhale cabin air for a full breath, exhaled air is not collected
• Used up to 40,000’ MSL

Quick-Don Mask

• Unimpeded access, can be donned with one hand in five seconds or less by flight crew
• Accommodates prescription glasses
• Used up to 40,000’ MSL

Pulse Oximeter

• Used to measure the amount of oxygen in an individual’s blood, in addition to heart rate
• Measures the color changes that red blood cells undergo when they become oxygen saturated
• Useful for non-pressurized aircraft operating above 12,500’ MSL where supplemental oxygen is required to evaluate the need for supplemental oxygen

Aviator’s Breathing Oxygen (ABO)

• Stored as gas in a low-pressure (400-450psi) or high-pressure (1800-2200psi) canister
• Must be ‘Aviator’s Grade Breathing Oxygen’ (not medical or industrial grade)

Liquid Aviator’s Breathing Oxygen (LOX)

• Stored as a liquid, but must be stored at critical temperature of -197ºF
• 900:1 expansion ratio (3:1 space savings and 5:1 weight savings over gas ABO

Sodium Chlorate Candles

• Stored as a solid ‘candle’, with a 600:1 expansion ratio
• Sodium chlorate thermally decomposes and releases oxygen when heated to 350ºF
• Once activated, the chemical reaction cannot be stopped easily and produces heat

Molecular Sieve Oxygen Generators (MSOG)

• Portable oxygen generator that uses ambient air to produce oxygen by separating nitrogen and inert gasses to supply the aircraft

Pressure

• Ensure that there is enough oxygen pressure and quantity to complete the flight

Regulator

• Inspect for proper function, ensure outlet and plug are compatible

Indicator

• Don the mask and check the flow indicator to ensure a steady flow of oxygen

Connections

• Ensure that all connections are secured (lines, plug-in, coupling, mask)

Emergency

• Available for hypoxia, smoke/fumes, decompression, DCS; brief passengers on location and use

FAR 91.211(a) – Supplemental Oxygen

Oxygen Requirements

Above 12,500’ MSL

Required for crew after 30 minutes

Above 14,000’ MSL

Required for crew

Above 15,000’ MSL

Available for everyone

FAR 91.211(b) – Supplemental Oxygen: Pressurized Cabin Aircraft

Above FL250

10 minute supply available for each occupant for use during decompression/emergency descent

Above FL350 or 14,000’ MSL Cabin Pressure

• One pilot at the controls must use an oxygen mask at all times – unless quick-don oxygen masks are available to both pilots (below 41,000’ MSL)
• One pilot must use an oxygen mask for the time the other pilot leaves the flight deck

Above FL410

One pilot at the controls must use an oxygen mask at all times

FAR 135.89 – Pilot requirements: Use of oxygen