A statistical evaluation on the cosmic radiation doses on aircrews flying over South America and Caribbean regions

Abstract

Introduction There are substantial researches on the cosmic radiation doses received by aircrew on their typical fl ight workload. Most part of these studies was made by measurements onboard aircrafts of some specifi c companies in stablished routes. A recurrent question from countries over South America and Caribbean regions is related on the signifi cance of doses accumulated by aircrews over this region and if those magnitude justifi es a specifi c radiation protection procedure. Methods The evaluation was made by statistical analysis using CARI-6 aircrew radiation dose code and the data are derived from comprehensive records of registered fl ights performed in the South America and Caribbean airspace between 29,000 and 41,000 feet, performed from March 7 to 20, 2009. The analysis of this sample was composed of 80,548 route calculations totalizing 53,163 hours of real fl ights, by means of calculation of each track performed by aircrafts between aeronautic navigation waypoints. Results The analysis identifi es that the typical group of fl ight crew operating over this region receives mean dose rates ranging from 2.65 μSv/h to 2.95 μSv/h depending on the solar cycle. This distribution, integrated over typical workload from Brazilian aircrews results on annual doses ranging from 1.45 mSv to 1.67 mSv. Conclusions The results demonstrate that the typical aircrew fl ying over this region exceeds the annual radiation limit for public (1 mSv). The statistical analysis also shows that this is the case of more than 96% of the aircrew fl ying with this fl ight routine and workload. The presented results can be used by local authorities of countries over this region as a basis to evaluate the convenience on adoption the recommendation from ICRP Publication 132 regarding radiation protection recommendations for aircrews.