Pilots' knowledge of the relationship between alcohol consumption and levels of blood alcohol concentration

The U.K. Civil Aviation Authority is currently proposing that a maximum BAC (Blood Alcohol Concentration) limit of just 0.02% should be imposed on United Kingdom pilots. In this survey of 477 pilots, it was found that a large proportion could not determine when their BAC was likely to fall below this level after drinking alcohol and could, therefore, potentially inadvertently infringe the proposed regulation. Another large proportion of pilots felt that they were safe to fly before their BAC had dropped below 0.02%, which may be indicative of a willingness to infringe the regulations. Estimates of when it was safe to fly also became more inaccurate as the amount drunk increased and varied with the type of alcoholic beverage consumed. It was also found that the conclusions drawn were heavily dependent upon the formula used to estimate BAC. This methodological problem identified has considerable implications for the study of alcohol consumption when flying.