The average, healthy person eliminates pure alcohol at a fairly constant rate - about 1/3 to 1/2 oz. of pure alcohol per hour, which is equivalent to the amount of pure alcohol contained in any of the popular drinks listed in Table 1.
A DEADLY COMBINATION
Alcoholic beverages, used by many to "unwind" or relax, act as a social "ice-breaker," is a way to alter one's mood by decreasing inhibitions. Alcohol consumption is widely accepted, often providing the cornerstone of social gatherings and celebrations. Along with cigarettes, many adolescents associate the use of alcohol as a rite of passage into adulthood.
While its use is prevalent and acceptable in our society, it should not come as a surprise that problems arise in the use of alcohol and the performance of safety-related activities, such as driving an automobile or flying an aircraft. These problems are made worse by the common belief that accidents happen "to other people, but not to me." There is a tendency to forget that flying an aircraft is a highly demanding cognitive and psychomotor task that takes place in an inhospitable environment where pilots are exposed to various sources of stress.
Hard facts about alcohol
The erratic effects of alcohol
Table 2 summarizes some of the effects of various blood alcohol concentrations. The blood alcohol content values in the table overlap because of the wide variation in alcohol tolerance among individuals.
0.01-0.05 average individual appears normal (10-50 mg%) 0.03-0.12* mild euphoria, talkativeness, decreased inhibitions, (30-120 mg%) decreased attention, impaired judgment, increased reaction time 0.09-0.25 emotional instability, loss of critical judgment, (90-250 mg%) impairment of memory and comprehension, decreased sensory response, mild muscular incoordination 0.18-0.30 confusion, dizziness, exaggerated emotions (anger, (180-300 mg%) fear, grief) impaired visual perception, decreased pain sensation, impaired balance, staggering gait, slurred speech, moderate muscular incoordination 0.27-0.40 apathy, impaired consciousness, stupor, significantly (270-400 mg%) decreased response to stimulation, severe muscular incoordination, inability to stand or walk, vomiting, incontinence of urine and feces 0.35-0.50 unconsciousness, depressed or abolished reflexes, (350-500 mg%) abnormal body temperature, coma; possible death from respiratory paralysis (450 mg% or above) * Legal limit for motor vehicle operation in most states is .08 or .10% (80-100 mg of alcohol per dL of blood).
Studies of how alcohol affects pilot performance
Year General Pilots with Piots with Aviation BAC BAC Pilot of of Fatilities 0.02% or more* 0.04% or more * 1987 341 13.5% 8.5% 1988 364 6.6% 6.3% 1989 349 12.9% 8.0% 1990 367 14.2% 7.9% 1991 379 12.9% 7.9% 1992 396 11.9% 7.3% 1993 338 12.7% 8.9% *Some cases may include alcohol produced after death by tissue decomposition. BAC= Blood alcohol concentration
Table 3. Fatal general aviation accidents with alcohol as possible contributing factor.
Studies of fatal accidents
Table 3 shows the annual alcohol-related pilot fatalities in general aviation accidents between 1987 and 1993, as reported by the Forensic Toxicology Research Section of the FAA Civil Aeromedical Institute. This information is based on the analysis of blood and tissue samples from pilots involved in fatal aviation accidents.
Hangovers are dangerous
A hangover effect, produced by alcoholic beverages after the acute intoxication has worn off, may be just as dangerous as the intoxication itself. Symptoms commonly associated with a hangover are headache, dizziness, dry mouth, stuffy nose, fatigue, upset stomach, irritability, impaired judgment, and increased sensitivity to bright light. A pilot with these symptoms would certainly not be fit to safely operate an aircraft. In addition, such a pilot could readily be perceived as being "under the influence of alcohol."
You are in control
Flying, while fun and exciting, is a precise, demanding, and unforgiving endeavor. Any factor that impairs the pilot's ability to perform the required tasks during the operation of an aircraft is an invitation for disaster.
The use of alcohol is a significant self-imposed stress factor that should be eliminated from the cockpit. The ability to do so is strictly within the pilot's control.
Keep in mind that regulations alone are no guarantee that problems won't occur. It is far more important for pilots to understand the negative effects of alcohol and its deadly impact on flight safety.
Ideally, total avoidance of alcohol should be a key element observed by every pilot in planning or accomplishing a flight.
Alcohol avoidance is as critical as developing a flight plan, a good preflight inspection, obeying ATC procedures, and avoiding severe weather.