The study of naturally-occurring radiation and its associated risk is one of the
preoccupations of bodies responsible for radiation protection. Cosmic particle flux
is significantly higher on board aircraft that at ground level. Furthermore, its
intensity depends on solar activity and eruptions. Due to their professional activity,
flight crews and frequent flyers may receive an annual dose of some millisieverts.
This is why the European directive adopted in 1996 requires the aircraft operators
to assess the dose and to inform their flight crews about the risk. The effective dose
is to be estimated using various experimental and calculation means. In France, the
computerized system for flight assessment of exposure to cosmic radiation in air
transport (SIEVERT) is delivered to airlines for assisting them in the application of
the European directive. This dose assessment tool was developed by the French
General Directorate of Civil Aviation (DGAC) and partners: the Institute for
Radiation Protection and Nuclear Safety (IRSN), the Paris Observatory and the
French Institute for Polar Research - Paul-Emile Victor (IPEV). This professional
service is available on an Internet server accessible to companies with a public
section. The system provides doses that consider the routes flown by aircraft.
Various results obtained are presented.