Tuesday, June 9, 2009

Aero Medical Facts (part 1 of 3)

Pilot performance can be seriously degraded by both prescribed and over-the-counter medications, as well as the medical conditions for which they are taken. Many medications such as tranquilizers, sedatives, strong pain relievers, cough suppressant preparations, antihistamines, blood pressure drugs, muscle relaxants, agents to control diarrhea and motion sickness have side effects that may impair judgment, memory alertness, coordination, vision, and the ability to make calculations. Medications to especially watch are antihistamines. Many over-the-counter cold formulas and inhalers have antihistamines. A stuffy nose might just be a reason not to fly.
As little as 1 ounce of liquor, 1 bottle of beer, or 4 ounces of wine can impair flying skills, alcohol consumed in these small amounts is detectable on the breath and in the blood for 3 hours. Don't discount the hangover. Flying under the influence or with the effects of alcohol is stupid as well as illegal. Since a pilot may be under the influence 8 hours after drinking moderate amounts of alcohol, a good rule of thumb is "12 hours between the bottle and the throttle." This is obviously only a rule of thumb, heavy drinking might call for a 24-hour rest prior to flying. You have to be the judge.FatigueThe Aeronautical Manual (AIM) describes fatigue as either acute (short term) or chronic (long term). Acute fatigue occurs daily due to strenuous muscular effort, mental strain, etc. Adequate rest along with proper diet and exercise is the best prevention. Chronic fatigue occurs when one does not fully recover from acute fatigue. With chronic fatigue, judgment becomes impaired and recovery requires prolonged rest. Fatigue is an insidious killer. One may become fatigued slowly over a period of time and not be aware of his/her condition If you think you are fatigued and if possible fly another day because fatigue can impair you decision making to a great extent.
Stress from everyday life can have a devastating effect on pilot performance. The fact is it's a rare person that can leave their difficulties on the ground. Stress like fatigue is insidious and when both are present, you are in an extremely dangerous situation.
Severe emotionally upsetting events including family troubles, death of a family member, loss of a job, or financial troubles can affect your ability to fly safely. Give yourself some healing time before your next flight
Hypoxia is a state of oxygen deficiency in the body sufficient to impair functions of the brain and other organs. When you increase altitude, the level of oxygen remains the same as ground level; however, the pressure needed to get the oxygen into your lungs just isn't there. Therefore, at altitudes above 5,000 feet your night vision is impaired and above 12,000 feet of altitude you may start suffering the effects of hypoxia. Hypoxia causes problems with judgment, memory, alertness, coordination, and the ability to make calculations. Physical effects you might notice are headache, drowsiness, dizziness and most serious of all, a profound sense of well being or perhaps belligerence. As altitude is increased the period of time before the onset of symptoms is shortened.
5,000 feet
Night vision impairment.
12,000 to 15,000 feet
Hypoxic symptoms begin.
Serious performance deteriorate within 15 min.Periphery
vision narrows causing a tunnel vision effect.Fingernails and lips turn blue
18,000 feet
Twenty to 30 minutes of useful consciousness. After that
pilot will be unable to take corrective action
20,000 feet
The pilot has 5 to 12 minutes until he/she is
totally unconsciousness

To prevent hypoxia above 10,000 feet during the day and 5,000 feet at night, pilots are encouraged to use supplemental oxygen.According to Federal Aviation Regulations (FARs) require that the flight crew use supplemental oxygen after 30 minutes of exposure to pressure altitudes between 12,500 and 14,000 feet. Above 15,000 feet, crew and passengers have to use supplemental oxygen.

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