This figure —0.24%—initiated a Canadian Transportation Safety Board recommendation to require substance abuse programs—including drug and alcohol testing—for all personnel engaged in safety-sensitive functions.
The safety recommendation was part of a final investigative report detailing the April 13, 2015, Carson Air cargo flight accident that killed a captain and first officer. Post-mortem toxicological screening revealed that the captain’s blood alcohol content was 0.24%—a level necessitating consumption of approximately 14 drinks over the previous 4-hr. period.
Given several witness statements and extensive research, the board concluded that the captain’s increased tolerance to the effects of alcohol likely allowed his impairment to go undetected for a long time and that intoxication “almost certainly” played a role in the accident.
As part of its recommendation, the Transportation Safety Board acknowledged Canadian criminal code and aviation regulation prohibitions on operating an aircraft while impaired by alcohol. It also recognized the Civil Aviation Medicine branch’s mandate to conduct regular medical fitness exams of aircrew members.
The board contended, however, that the current framework relies too heavily on self-policing and voluntary disclosure. After citing previous accident investigations in which drugs and alcohol were contributing factors, the board concluded: “There is an increased risk that undisclosed cases of drug or alcohol dependence in commercial aviation will go undetected, placing the traveling public at risk.”
While the board did not specifically dictate the type of personnel that should be considered safety-sensitive for purposes of substance abuse programs, it referenced International Civil Aviation Organization classifications, which include in their definition any employee “who might endanger aviation safety if they perform their duties and functions improperly.”
The U.S., Australia and the UK have mandated drug and alcohol abuse prevention programs for aviation personnel. As the safety board pointed out, in the U.S. and Australia, safety-sensitive personnel include those who perform aircraft maintenance functions.