George O’Connor, Jr., ATP, CFII,

MEI

Introduction The Atmosphere Hypoxia and Hyperventilation Medical Factors Oxygen Systems Questions

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Composition to 300,000 ft.

Nitrogen 78%

Oxygen 21%

Trace Gases 1%

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Definition:

A state of oxygen deficiency in blood, cells and tissues sufficient to impair

human functions

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At Sea Level O2Hb Sat = 98%At 10,000 ft O2Hb Sat = 87%

Threshold for Hypoxic Hypoxia

At FL340 O2Hb Sat = 33%Insufficient to Support Life

At FL340 w/100% O2 O2Hb Sat = 98%At FL430 w/100% O2 O2Hb Sat = 72%At FL430 w/100% O2 Under Pressure O2Hb Sat = 87%

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Altitude Rate of ascent Duration of

exposure Environmental

Pressure Physical fitness

Individual tolerance Physical activity Psychological Medication and

drugs

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Euphoria Lightheadedness Apprehension Headache Dizziness Fatigue Nausea

Hot/cold flashes Blurred vision Tunnel vision Tingling Numbness Anger Belligerence

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Increase in rate and/or depth of breathing

Cyanosis Mental confusion Poor judgment Loss of muscle coordination Euphoria Belligerence Unconsciousness

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The abnormal increase in the rate and depth of breathing

Caused by an abnormally low level of carbon dioxide in the blood

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Anxiety Emotions Fear Apprehension Pain Pressure breathing Hypoxia

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Do not panic

Control your rate and depth of

breathing

Check your oxygen equipment – it

may be hypoxia

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FAR 91.211

•At cabin pressure altitudes above 12,500 feet (MSL) up to and including 14,000 feet (MSL) unless the required minimum flight crew is provided with and uses supplemental oxygen for that part of the flight at those altitudes that is of more than 30 minutes duration;

At cabin pressure altitudes above 14,000 feet (MSL) unless the required minimum flight crew is provided with and uses supplemental oxygen during the entire flight time at those altitudes; and(3) At cabin pressure altitudes above 15,000 feet (MSL) unless each occupant of the aircraft is provided with supplemental oxygen.

The amount of time an individual is able to perform flying duties

efficiently in an environment with inadequate

oxygen supply.

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FL180……..20 – 30 minutesFL220………8 – 10 minutesFL250………..3 – 5 minutesFL280…….. 2.5 – 3 minutesFL300………..1 – 2 minutesFL350……..30 – 60 secondsFL400……..15 – 20 secondsFL430………9 – 12 secondsFL500………9 – 12 seconds

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Don oxygen masks/mic switches

Assure oxygen flow

Initiate rapid descent to 10,000 ft.

Advise ATC as soon as practicable

Check on crew and passengers

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Caused by upper respiratory infections

Usually occurs on descent Can occur on ascent Severe, sudden pain

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Stop descent/ascent Valsalva Cough against pressure Reverse direction of the

pressure change• Vasoconstrictors (on descent only)

• See Flight Surgeon

Normal Inner ear Exposure to External Pressure

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DECOMPRESSION SICKNESS

TINY BUBBLES = BIG TROUBLE

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Gastrointestinal Gas Expansion is the most common symptom experienced with a rapid decompression.• Not serious at low or

intermediate altitudes• Above FL250 enough

distention may occur to produce severe pain which can result in unconsciousness

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10,000 feet 1.5 liters FL200 2.4 liters FL300 4.0 liters FL400 7.6 liters FL430 9.0 liters FL500 17.0 liters

1 liter of gas at ground level expands to:

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CHECK OXYGEN PRESSURECHECK OXYGEN PRESSURE

JULY - 600 psi JANUARY - 550 psi

When volume is constant, the pressure of a gas increases or decreases proportionally to an increase or

decrease in its temperature.

At 1800 PSI and 32F = 80% Usable Capacity

2 Pilots + 2 Passengers = 6 using oxygen Assuming a 50(cu ft) O2 tank 52 minutes corrected for 80% = 42 minutes 02

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An adequate P.R.I.C.E. Check before, during, and after your flight should ensure your emergency equipment will work when you depend on it to

save your life.

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Pressure

Regulator

Indicator

Connections

EMERGENCY

P

R

I

C

E

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P ressureressure

Check for adequate pressure readings on BOTH the refiller

port site and the instrument panel.The readings should match.

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R egulatoregulator

Check for oxygen flow in BOTH the Normal and 100% settings.

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I ndicatorndicator

Ensure the indicator shows you are getting oxygen flow.

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C onnectionsonnections

Check connections to makesure all are tightly connected.

Check by pushing further together rather than trying to

pull apart.

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Explosive − Total cabin pressure loss in less

than 1 second Rapid Decompression

− Total cabin pressure loss in less than 1 – 10 seconds

− Danger from pressure differential Slow Decompression

− Total cabin pressure loss in greater than 10 seconds

− Danger from insidiousness

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Disadvantages of PressurizationDisadvantages of Pressurization

PRIMARY AND MOST CRITICAL

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• KING AIR 200

• TWO PILOT CREW

• CRUSING AT FL270

• WINDSHIELD SHATTERED

• PILOTS DUMPED CABIN

• NO OXYGEN MASKS DONNED

• AIRCRAFT ENTERED TERMINAL VELOCITY

• Regained Comsciousness at 13,000 MSL

• Regained Control at 7,000 MSL

• Radar indicated they lost 20,000 feet in 90 seconds

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