High concentrations of carbon dioxide (CO2) were linked to a decrease in pilot performance in a simulator study that assessed the likelihood of flying an acceptable maneuver in atmospheres containing varying concentrations of CO2.
In a report published last week in the Journal of Exposure Science & Environmental Epidemiology, researchers said that, knowing that higher-than-typical concentrations of CO2 adversely affect the cognitive function performance of office workers, they sought to determine whether pilots’ functioning would be similarly affected.
The report cited earlier research that suggested that CO2 levels previously thought to be safe (from 1,000 to 2,500 parts per million [ppm]) resulted in problems in office workers’ performance. CO2 concentrations on the flight desk typically are less than 1,000 ppm but sometimes range as high as 1,400 ppm, the report said.
In the study, 30 commercial airline pilots flew three three-hour flight segments, including maneuvers of varying complexity, in a flight simulator with a different CO2 concentration for each flight segment — 700 ppm, 1,500 ppm and 2,500 ppm.
“The pilots … were assessed by a [U.S. Federal Aviation Administration] FAA designated pilot examiner according to FAA Practical Test Standards,” the report said. “Compared to segments at a CO2 concentration of 2,500 ppm, the odds of passing a maneuver as rated by the examiner in the simulator were 1.52 … times higher when pilots were exposed to 1,500 ppm and 1.69 … times higher when exposed to 700 ppm, controlling for maneuver difficulty, examiner and order of maneuvers.”
The findings “suggest that there is a direct effect of carbon dioxide on performance, independent of ventilation, with implications for many other indoor environments that routinely experience CO2 concentrations about 1,000 ppm,” the report said.