Cosmic radiation exposure of airline crews in France over the period 2015–2019

Cosmic particle flux increases with latitude and altitude and is significantly higher on-board aircraft than at ground level. Furthermore, its intensity depends on solar activity and eruptions. Due to their professional activity, flight crews (FCs) may receive an annual dose of some millisieverts. Therefore, the European directive adopted in 1996 requires the aircraft operators to assess the dose. The effective dose is to be estimated using various experimental and calculation means. In France, it is carried out by the computerized system for flight assessment of exposure to cosmic radiation SIEVERTPN, which sends to SISERI, the national dose registry, the monthly effective dose of each crew member. The average annual effective dose of French FCs was 2.19 mSv in 2019, i.e. between the standard permissible limits set for the public and the limit set for occupationally exposed persons. The effective dose received by the most exposed French FCs increased during the period 2015–2019 and that could be due to the solar cycle effect, changes in the staff flight time or the aircraft model. It can also be noted that more technical flight crews (TFCs) received a dose greater than 5 mSv over the 2016 to 2019 period than commercial flight crew (CFCs). Our study indicates that the number of FCs having received a dose greater than 5 mSv also increased over the period 2016 to 2019. Some parameters, that may affect the assessment of the aircrew effective dose, are not considered in SIEVERTPN calculations, as for example the Forbush decreases and the location in the plane. Lastly, several factors lead us to expect a decrease in the doses received by French aircrew staff in the coming years, such as the peak activity of the 25th eleven-year solar cycle expected in July 2025. However, some unexpected events, as for instance the war in Ukraine, can alter this prediction.