Medical Handbook For Pilots Chapter 08 – Alcohol

Everyone knows that alcohol impairs the efficiency of the human mechanism. This fact has been emphasized again and again-in newspapers, magazines, television, and other media throughout the world. Studies have positively proved that drinking and performance deterioration are closely linked. Estimates indicate that alcohol is a major factor in nearly 50% of all automobile accidents. Analyses of aircraft accidents over the past several years implicated alcohol as a contributing factor in almost 40% of the crashes in the early 1960’s. Discovery of the problem, education, and regulation had decreased this factor to around 20% in the late 1960’s and early 1970’s.

In “hangar sessions” among experienced pilots, there is almost 100% agreement that drinking and flying don’t mix. Yet, the accident record shows that far too many pilots have ignored their own better judgment and paid with their lives. An automobile moves in only two dimensions. An airplane moves in three, making its safe operation infinitely more complex. Therefore, any pilot who is not in top condition is severely handicapped. Even straight-and-level flight from one point to another requires a high degree of judgment, attention, coordination, and skill. Hundreds of decisions must be made, some on the basis of incomplete information (adverse weather, etc.). Obviously, then, anything which detracts from your ability to make successive decisions which are correct will increase your chances of having an accident.

What is alcohol; and how does it affect your performance as a pilot? The alcohol you consume in beer and mixed drinks is simple ethyl alcohol, a central nervous system depressant. From a medical point of view, it acts upon your body much like a general anesthetic (ether, chloroform, etc.). The “dose,” of course, is generally much lower and more slowly consumed in the case of alcohol. But the basic effects on your system are similar.

Alcohol is easily and quickly absorbed by the digestive tract. Your blood stream absorbs about 80% to 90% of the alcohol in a highball within 30 minutes after you have drained your glass. Beer works a little slower, but not much.

You have undoubtedly heard time and again that alcohol is a depressant, not a stimulant. Yet after one or two drinks you certainly feel stimulated. This sensation is misleading and occurs because part of the depressant action of alcohol, working on the brain, brings about a release from the usual restraints and inhibitions. You may enjoy a feeling of security, well-being, confidence, and freedom from pressure. In reality, however, your thinking has become sluggish, you respond to urgent situations less efficiently, and your ability to perform simple tasks with speed and accuracy is hampered. If, in addition, you happen to be fatigued, hungry, or under stress, these handicaps will be compounded.

The effect of alcohol is greatly multiplied when a person is exposed to altitude. Two dunks on the ground are equivalent to three or four at altitude. The reason for this is that, chemically, alcohol interferes with the ability of the brain to utilize oxygen. The effects are rapid-first because alcohol passes so quickly into the bloodstream, and second because the brain is a highly vascular organ, immediately sensitive to changes in the blood’s composition. For the pilot, then, the lower oxygen availability at altitude, along with the lower capability of his brain (under the influence of alcohol) to use what oxygen is there; adds up to a deadly combination.

Your body requires about 3 hours to rid itself of all the alcohol contained in one mixed drink or one beer. The Federal Aviation Regulations make it illegal to fly for at least 8 hours after taking a single drink. Most wise pilots allow a minimum of 12 hours between “the bottle and the throttle.” The general rule for commercial airlines is 24 hours.

The subtle effects of a hangover can be just as hazardous as the state of intoxication itself. Morning-after weariness dulls your system and detracts from peak efficiency. Recent research by the FAA’s Office of Aviation Medicine indicates that some functions may require up to 2 days for complete recovery following a “binge.”

Do not drink alcohol in any form during the 8-hour period preceding flight, and do not overindulge during the 24 hours before flight. Don’t invite disaster by letting alcohol and hypoxia gang up on you!