Aeromedical Commentary

General Information for Aeromedical

The pilot is the weakest part of an aircraft. The more you know about how your own biology interacts with the conditions of flight, the better prepared you are to accommodate it, and to know when it would be unsafe to fly.

Question-by-Question Explanation of Aeromedical

8.01 As it says in CARs 404.06, you may not "exercise the privileges of the permit, licence or rating" if you are under a physical disability. That means you may not fly.  You don't have to tell Transport nor turn in your licence. It makes no difference whether you are captain or first officer or whether your passenger is a pilot. You can still be a passenger, of course. It might be unwise, but it's not illegal.

8.02 The symptoms of hyperventilation (breathing too quickly and deeply) are similar to the symptoms of hypoxia (not getting enough oxygen).  At high altitudes, rather than trying to tell the difference, you give the person some oxygen and if that doesn't help within three or four breaths, then you treat for hyperventilation.  Below 8000', it is very unlikely someone could become hypoxic, so you immediately treat for hyperventilation, which requires the person to breath slowly, and not so deeply.

(1) During a climb, the pressure inside the ear is greater than the pressure outside the ear, and the pressure tends to release with very little problem. Your ears "pop." This is the pressure inside your ears escaping through the eustachian tubes that connect your middle ear to the back of your throat.
(2) During a descent, the pressure outside is greater, and that pressure difference tends to close the eustachian tubes so pressure cannot equalize. If you continue to descend, damage to the eardrum could result. As you fly more, you will probably find that you can handle more rapid descents, but you must remember that your passengers are not necessarily so acclimatized. Make it a rule for yourself to use 500 fpm as a maximum descent rate with passengers, or 300 fpm if a small child is on board.
(3) Using 100% oxygen can result in ear pain some hours after the flight, as the pure oxygen trapped in your middle ear is absorbed by the tissue, leaving lower pressure.
(4) When flying after SCUBA diving, damage to joints can occur, but not to ears.

Eustacian tubes

(1) Using the swallowing muscles can help to open the eustachian tubes, giving an opportunity for pressure to release.
(2) Yawning also helps to open the eustachian tubes.
(3) The Valsalva manoeuver consists of plugging your nose, closing your mouth and blowing out through your ears. That sounds ludicrous, but it is the most effective equalizing technique. However, doing a Valsalva (or pressurizing your ears by climbing to altitude) when you have a cold can force bacteria into your middle ear, causing an ear infection.

8.05 A SCUBA diver's training includes information on how long she must wait between diving and flying, but if you know one of your passengers is a diver, it doesn't hurt to ensure they have waited long enough. If you are going to fly above 8000', the diver must always wait 24 hours before flight. If you will be flying below 8000' and the dive has not required decompression stops, 12 hours should be sufficient.

(1) Financial or family problems definitely contribute to fatigue.
(2) When a normally attentive student starts skipping checklist items, forgetting flaps or taxiing for the wrong runway, I ask him, "did you get enough sleep last night? Is there anything on your mind?" I tell my students not to hesitate to cancel a lesson if they have not slept properly or have worries at home. The difference in piloting performance is dramatic. CARs 602.02 forbid you to fly if you are fatigued or are likely to become fatigued during the flight.
(3) Altitude increases fatigue.
(4) Hunger increases fatigue, too, but the answer is that a fatigued person should not fly at all, food or no food.

The A.I.P. recommends against donating blood at all if you are an active pilot, but says if they do, to wait 48 hours.

Usually a general anaesthetic is administered for an operation, which itself might be a reason not to fly, notwithstanding any delayed reaction to the anaesthetic. Your doctor can tell you when it's safe to fly.

The A.I.P. doesn't make this one mandatory, leaving room for judgement on the part of the pilot. If your jaws are throbbing and you're drooling blood, go home, not to the\airport.  The A.I.P. says, "common sense suggests waiting at least 24 hours before flying."

The higher the altitude, the less it takes to get you drunk. The law says to wait at least eight hours before flying, but the A.I.P. recommends at least 24 hours. Alcohol impairs judgement and balance, and you need both when flying.  Here's a joke about that.

(1) The manufacturer may not know the effects of the drug at altitude.
(2) The question asks which is the safest rule and this is definitely it. If there are over the counter drugs you want to take, bring them along to your next medical and ask the CAME if they are permissible, and if not, how long you should wait before flying.
(3) & (4) You have no way of knowing how long the drug or its side effects will persist in your system.

8.12 & 8.13
The table in CARs 424.04 is out of date and so is AIP-LRA 3.2.4 when giving the validity period of a medical for different licence holders. This document on the Transport Canada site announces the changes that are now in effect. A medical used be valid for two years for a private pilot under 40 and one year for a private pilot 40 and up.  It is now five years (60 months) for the private pilot under 40 and two years (24 months) for the private pilot who has reached 40.  If you have one of these questions on your PSTAR, make sure it isn't marked with an outdated answer key. You can't afford to lose more than five marks on the whole test.  

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This page written 8 October 2002 by Robyn Stewart.  Last revised 3 July 2003.

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