Human factors · Canadian Paragliding Exam Study Guide

Hypoxia: not enough oxygen

Hypoxia is a lack of sufficient oxygen in the blood (and therefore in the brain). As you climb, the air pressure drops and each breath brings less oxygen. At 10,000 ft (3,000 m) most people are already mildly affected; at 18,000 ft the pressure is half of sea level.

Why it is dangerous: the body has no alarm for hypoxia. An early symptom is often euphoria, a feeling of well-being and confidence, while judgment and reactions are already getting worse.

Warning signs: a tingling sensation in the fingers and toes, euphoria, headache, dizziness, blue lips or fingernails, poor judgment, slow reactions, narrowed or dim vision, unusual fatigue, then unconsciousness. Exam answer for "warning signs of hypoxia": tingling in the tips of the toes and fingers and a great feeling of euphoria → both.

Must-pass idea: the warning signs of hypoxia

The P4 asks for the warning signs of hypoxia at high altitude as a † question. The answer is both: a tingling sensation in the tips of the fingers and toes and a great feeling of euphoria. It is wrong to say "there are no signs"; the signs exist, but euphoria makes you ignore them.

Relief: descend and/or breathe supplemental oxygen.

What makes hypoxia worse at the same altitude: alcohol (their effects add together: one drink at 6,000 ft is like two at sea level), smoking (carbon monoxide takes the place of oxygen in the blood), fatigue, cold, being out of shape or living at sea level, and a recent blood donation. Altitude also reduces visual acuity, especially at dusk.

The oxygen rules (CAR 605.31 and 605.32)

Between 10,000 and 13,000 ft ASL: you may fly at most 30 minutes without supplemental oxygen. Any longer and you must be using oxygen.
Above 13,000 ft ASL: oxygen is always mandatory, for the whole time you are above 13,000 ft.
The oxygen supply you carry must last for the whole period that requires it (the whole time above 13,000 ft, and the time beyond 30 minutes between 10,000 and 13,000 ft). There is no "one hour is enough" rule for private pilots; that figure is for commercial air transport.
Below 10,000 ft no oxygen is required, but the HAGAR guide recommends staying below 10,000 ft without oxygen if you are unfit or live at sea level.

Nepal bridge: you fly higher than most Canadians

Flying at 4,000–5,000 m near Annapurna is normal for some of you, and you know the headache and the cold. Canadian law puts numbers on it: 10,000 ft, 30 minutes, 13,000 ft. Learn them in feet. And remember that on a tandem you are responsible for the passenger's oxygen too.

Hyperventilation: breathing too much

Hyperventilation is breathing faster or deeper than your body needs. It is usually caused by anxiety, fear, tension or intense concentration, for example in your first strong thermal or during a collapse. Breathing too much blows off carbon dioxide and upsets the balance of oxygen and carbon dioxide in the blood; the brain gets less blood.

Symptoms look like hypoxia: dizziness, tingling in the hands and feet, a tight band around the head, a feeling of cold, cramps and spasms of the hands, and, strangely, a feeling that you cannot get enough air. It can happen at any altitude, including on launch.

Treatment: consciously slow your breathing to about 10–12 breaths per minute, breathe shallowly, talk out loud, or breathe into cupped hands. Supplemental oxygen does not treat hyperventilation (there is already plenty of oxygen; the problem is too little carbon dioxide).

Which statement about hyperventilation is FALSE?

True: it has symptoms similar to hypoxia and can occur at any altitude. True: it causes an oxygen–carbon dioxide imbalance. True: it is often caused by tension or anxiety. False: its treatment requires supplemental oxygen. Slow breathing is the treatment.

Alcohol

CAR 602.03: alcohol and drugs

No person shall act as a crew member of an aircraft within 12 hours after consuming an alcoholic beverage, while under the influence of alcohol, or while using any drug that impairs the person's faculties to the extent that safety is endangered. You may not carry a passenger who is intoxicated (CAR 602.04). That last rule matters for tandem pilots.

12 hours, not 8

Older Canadian study material and some older exam questions say 8 hours. The regulation was changed in December 2018 to 12 hours. Learn 12. Transport Canada's own advice is even stricter: allow at least 24 hours between the last drink and take-off, because the body clears alcohol at a fixed rate and coffee, food, oxygen or sleep do not speed it up.

Why alcohol is so bad for pilots: even 0.05% blood alcohol measurably reduces piloting skill; alcohol collects in the fluid of the inner ear and stays there after the blood is clear, which causes the poor balance and disorientation of a hangover; it reduces visual acuity; and its effects add to hypoxia.

Drugs and medications

Take no medicine before flying unless a Civil Aviation Medical Examiner (CAME) or a doctor familiar with aviation has said it is safe. This is the exam's preferred answer over "allow 8 hours", "allow 48 hours to check side effects", or "only common over-the-counter remedies".
Antihistamines (for hay fever and allergies), cough medicines, sleeping pills and appetite suppressants do adversely affect a pilot: drowsiness, slower thinking, worse coordination. The statement "antihistamines do not adversely affect the pilot" is false.
Herbal remedies and energy supplements count too.
Illegal drugs, including cannabis, and flying do not mix, and impairment can last far longer than the "high".

The combination question (P4)

True statements: blood donation increases the effect of hypoxia; alcohol decreases visual acuity; higher altitude decreases visual acuity; alcohol in the inner-ear fluid causes disorientation. False statements: "antihistamines do not affect the pilot"; "smoking increases visual acuity" (smoking decreases it). When the exam lists six statements and asks for the correct combination, tick each one T or F first.

Fitness to fly: the IMSAFE check

CAR 602.02 says you may not act as a pilot if you have any reason to believe you are fatigued or otherwise unfit. Before every flight run IMSAFE:

Illness: a cold blocks your ears and sinuses; fever slows your brain.
Medication: anything taken in the last 24 hours?
Stress: family, money, work. Stress eats attention.
Alcohol: 12 hours minimum by law, 24 hours recommended.
Fatigue: the number-one hidden cause of bad decisions.
Emotion / Eating: upset, angry, hungry, dehydrated?

Peer pressure and ego are human factors too: the desire to fly because others are flying, or to look good, has killed many experienced pilots.

Decompression sickness (the bends) and scuba diving

At altitude, nitrogen dissolved in your tissues can form bubbles: pain in the joints (the bends), and in bad cases chest pain or collapse. It is rare below 20,000 ft unless you have been scuba diving, which loads the body with extra nitrogen. Then it can occur as low as 8,000 ft.

After a no-decompression dive: do not fly for 12 hours.
After a dive that needed decompression stops, or before any flight above 8,000 ft: wait 24 hours.
Remedy in flight: descend.

Ears and sinuses

Air in the middle ear and sinuses expands as you climb and escapes easily. On descent, especially a fast one, the air must get back in through the narrow Eustachian tube. If you have a cold or throat infection, the tube can close like a flap, the eardrum is pushed in, and you get severe pain, reduced hearing, even a burst eardrum (barotrauma).

Clear your ears by swallowing, yawning, chewing, moving the jaw, or holding the nose and blowing gently (Valsalva). If the pressure will not clear, climb a little, clear the ears, and descend slowly, clearing often. Do not fly with a heavy cold.

Vision and scanning

Flying VFR is see and be seen. Vision is your main collision-avoidance instrument, and it is affected by hypoxia, carbon monoxide, alcohol, drugs, fatigue and smoking. Wear the correct prescription glasses and good sunglasses.

Scan the sky in sectors, and regularly focus on a distant object to avoid empty-field myopia, where the eyes relax to a short focus and you stop seeing distant aircraft against an empty sky. In a gaggle, scan constantly between the gliders near you; increase separation in turbulence (a collapse can move a wing sideways very fast); and if you are uncomfortable, leave the gaggle.

Disorientation

Spatial disorientation is a wrong sense of position, attitude or movement. On the ground you orient by vision, by muscle sense, and by the inner ear (which senses acceleration). In cloud, in whiteout or over featureless terrain, vision fails and the inner ear lies: in a prolonged steady turn (a spiral!) the sense of turning fades, and when you stop the turn you feel you are turning the other way. This has caused many accidents.

Rules: never lose sight of the ground, never enter cloud, and be ready for false sensations when exiting a long spiral.

Cold and dehydration

Temperature drops about 2 °C per 1,000 ft (about 6.5 °C per 1,000 m). A 30 °C launch can mean 5 °C at cloud base. Hypothermia brings shivering, clumsiness, confusion and bad decisions. Dress for altitude, wear gloves, and drink before and during long flights: dehydration mimics fatigue and worsens hypoxia.

The Category 4 medical (for HAGAR and Class E)

To fly in Class E airspace with a HAGAR, the CARs require a Category 1, 3 or 4 medical certificate. Hang glider and paraglider pilots use the Category 4:

You complete a medical declaration (Transport Canada form 26-0297), sign it, have it witnessed, and email it to a Transport Canada Centre. No doctor's examination is needed unless you have one of the conditions listed on the form. If you do, you must be examined by a Civil Aviation Medical Examiner (CAME), not a family doctor.
Transport Canada's service standard for a new medical certificate is 40 working days. Apply early.
The certificate must be in your hands before you write the HAGAR, and the examiner may ask to see it.
A glider-type Category 4 certificate is valid for 60 months (5 years).

Key numbers from this module

Oxygen: 10,000–13,000 ft ASL max 30 min without; above 13,000 ft always; supply for the whole period.
Alcohol: 12 hours by law (was 8 before Dec 2018); 24 hours recommended; no intoxicated passengers.
Hyperventilation treatment: slow breathing (10–12/min), not oxygen.
Diving: 12 h after a no-decompression dive; 24 h after decompression dives or before flying above 8,000 ft.
Hypoxia signs: tingling fingers/toes + euphoria.
Temperature drops about 2 °C per 1,000 ft.
Category 4 medical: declaration form 26-0297, witnessed, 40 working days, CAME only if a listed condition applies.