FAA OFFICE OF AVIATION MEDICINE  CIVIL AEROMEDICAL INSTITUTE  PUBLICATIONS

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

• It's a sedative, hypnotic, and addicting drug.
• Alcohol quickly impairs judgment and leads to behavior that can easily contribute to, or cause accidents.

The erratic effects of alcohol

• Alcohol is rapidly absorbed from the stomach and small intestine, and transported by the blood throughout the body. Its toxic effects vary considerably from person to person, and are influenced by variables such as gender, body weight, rate of consumption (time), and total amount consumed.

• 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. This rate of elimination of alcohol is relatively constant, regardless of the total amount of alcohol consumed. In other words, whether a person consumes a few or many drinks, the rate of alcohol elimination from the body is essentially the same. Therefore, the more alcohol an individual consumes, the longer it takes his/her body to get rid of it.

• Even after complete elimination of all of the alcohol in the body, there are undesirable effects-hangover-that can last 48 to 72 hours following the last drink.

• The majority of adverse effects produced by alcohol relate to the brain, the eyes, and the inner ear-three crucial organs to a pilot.

• Brain effects include impaired reaction time, reasoning, judgment, and memory. Alcohol decreases the ability of the brain to make use of oxygen. This adverse effect can be magnified as a result of simultaneous exposure to altitude, characterized by a decreased partial pressure of oxygen.

• Visual symptoms include eye muscle imbalance, which leads to double vision and difficulty focusing.

• Inner ear effects include dizziness, and decreased hearing perception.

• If other variables are added, such as sleep deprivation, fatigue, medication use, altitude hypoxia, or flying at night or in bad weather, the negative effects are significantly magnified.

  
  

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  Type Beverage   Typical Serving   Pure Alcohol   
                       (oz.)        Content (oz.)  
  
  Table Wine             4               .48       
  
  Light Beer             12              .48       
  
  Aperitif              1.5              .38       
  Liquor                                           
  
  Champagne              4               .48       
  
  Vodka                  1               .50       
  
  Whiskey               1.25             .50       
  
  
  
  Table 1. Amount of alcohol in various alcoholic beverages.

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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).

Table 2. Some of the effects of various blood alcohol concentrations.

Studies of how alcohol affects pilot performance

• Pilots have shown impairment in their ability to fly an ILS approach or to fly IFR, and even to perform routine VFR flight tasks while under the influence of alcohol, regardless of individual flying experience.

• The number of serious errors committed by pilots dramatically increases at or above concentrations of 0.04% blood alcohol. This is not to say that problems don't occur below this value. Some studies have shown decrements in pilot performance with blood alcohol concentrations as low as the 0.025%.

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                        

Studies of fatal accidents

Hangovers are dangerous

You are in control

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.
 

Federal Aviation Regulation (FAR) 91.17 The use of alcohol and drugs by pilots is regulated by FAR 91.17. Among other provisions, this regulation states that no person may operate or attempt to operate an aircraft:  within 8 hours of having consumed alcohol  while under the influence of alcohol  with a blood alcohol content of 0.04% or greater  while using any drug that adversely affects safety

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.

General Recommendations

1. As a minimum, adhere to all the guidelines of FAR 91.17:
   • 8 hours from "bottle to throttle"
   • do not fly while under the influence of alcohol
   • do not fly while using any drug that may adversely affect safety
2. A more conservative approach is to wait 24 hours from the last use of alcohol before flying. This is especially true if intoxication occurred or if you plan to fly IFR. Cold showers, drinking black coffee, or breathing 100% oxygen cannot speed up the elimination of alcohol from the body.
3. Consider the effects of a hangover. Eight hours from "bottle to throttle" does not mean you are in the best physical condition to fly, or that your blood alcohol concentration is below the legal limits.
4. Recognize the hazards of combining alcohol consumption and flying.
5. Use good judgment. Your life and the lives of your passengers are at risk if you drink and fly.

Alcohol avoidance is as critical as developing a flight plan, a good preflight inspection, obeying ATC procedures, and avoiding severe weather.
 

ALCOHOL USE IN AMERICA Over 50% of American adults consume alcohol.  Per capita consumption is about 25 gallons per year.  Alcoholic beverages are marketed in a variety of forms, with wine and beer being the most liked.  Different alcoholic beverages have different concentrations of alcohol; however, their total alcohol content can be the same. For example, a pint of beer contains as much alcohol as a 5 1/2 ounce glass of table wine. Therefore, the notion that drinking low-concentration alcoholic beverages is safer than drinking hard liquor is erroneous.  The total alcohol content of any alcoholic beverage can be easily calculated using the following formula: "Proof" divided by 2 = percent pure alcohol.

 

Medical Facts for Pilots Publication AM-400-94/2  Written by: Guillermo J. Salazar, M.D.  Melchor J. Antuñano, M.D.  Prepared by: FAA Civil Aeromedical Institute  Aeromedical Education Division  AAM-400, P.O. Box 25082  Oklahoma City, Oklahoma 73125