The study of “external†radiation called cosmic radiation that strikes the earth from anywhere beyond the atmosphere is of great importance in radiation protection. All human beings are exposed to an uncontrollable amount of cosmic radiation on the ground level. Those who travel in space, airline crews and frequent flyers are exposed to additional level of cosmic radiation during their trip but unfor-tunately many of them are not aware of this. This workcalculates the exposure of aircrews and fre-quent flyers to cosmic radiation during travel along some air routes to and from Nigeria. The effective dose was computed using a dedicated software CARI 6M, developed by US FAA.The study focuses on the significance of the in-flight exposure, assessment and estimation of in-flight exposure using the dedicated software and some ways of controlling the exposures so that airline crews and frequent flyers are not exposed to fatal levels of radiation.It was observed that the cosmic radiation doses re-ceived by passengers and crew members on board on flights from Lagos Nigeria to countries in Amer-ica were more than what they received en-route countries in Asia.
Measurements of Cosmic Radiation Doses in Civil Aircraft by Pocket Dosimeter : Resuls for Domestic Aviation Routes in Japan