2015
Volume 15, Number 4, pp. 204-208
Flight crew exposure to bleed air and health effects: what is the problem?
C. van Netten
Professor Emeritus, School of Population and Public Health, Faculty of Medicine, University of British Columbia, 2206 East Mall, Vancouver, B.C., Canada, V6T 1Z3
Flight crew members have suffered, and currently are suffering, from health effects alleged to be caused by exposure to contaminated air from the ventilation system within the aircraft due to sporadic leakage of oil seals inside the engines (i.e., bleed air events). In order to obtain some sort of recognition from their employers that the health complaints are work-related, the affected individuals have to provide objective evidence that this is indeed the case. This article identifies some of the agents that can be expected to be present in the air when jet turbine oils, and some hydraulic fluids, are exposed to temperatures that are associated with normal engine operation. These agents include, among others, formaldehyde, carbon monoxide and tricresyl phosphate isomers. Since air quality monitoring for these agents is not done in aircraft, a small air sampler was developed that can be deployed by flight crew members when they encounter a bleed air event, providing objective evidence to the employer of air exposure. Since turbine oils contain a characteristic set of tricresyl phosphate isomers, their presence in the air indicates oil seal leakage and exposure to all the other agents associated with bleed air events.
Keywords: aircraft air contaminants, carbon monoxide, exposure measurement, formaldehyde, personal air sampler, tricresyl phosphate