CHAPTER 13 Inflight Radiation Exposure  PAGE 13-1
13. Inflight Radiation Exposure
13.1  FAA Advisory Circular AC 120-61A provides guidance information for use by Airlines for training their crew about inflight radiation exposure when operating Polar flights. It also gives other links on radiation exposure information.
13.2  Cosmic radiation levels in the atmosphere vary with latitude, longitude, altitude, solar activity and solar flare. Airplane crews and passengers are exposed to a higher level of radiation when they fly, accumulating radiation doses that depend primarily on the route taken and the altitude profile of the flight. Flights on polar routes experience higher levels of cosmic radiation than equatorial routes. Radiation levels reach a plateau and do not increase much more above approximately 55 deg. north or south latitude. Thus, flights over the pole receive similar radiation doses as flights that avoid the pole by following the 55 deg. latitude line. If flying over the pole decreases the flight time, a lower radiation dose can be expected because of the decreased exposure time.
13.3  Airplane crews flying exclusively on polar routes will receive about one-third of the average annual maximum dose established by the International Commission on Radiological Protection (ICRP). This is similar to the radiation dose on routes such as Athens to New York, and does not pose a significant health risk.
13.4  Below are actual radiation measurements recorded in millisieverts on Two flights between New York (KJFK)and Beijing (ZBAA) and between Beijing and Atlanta International Airport (KATL).
Measurements for KJFK-ZBAA
Trip Duration: ~15 hours
Exposure/Hour .007 mSv/hour
Exposure (Total) .11 mSv

Measurements for ZBAA-KATL
Trip Duration: ~13 hours
Exposure/Hour .009 mSv/hour
 Exposure (Total) .13 mSv

13.5  Total exposure (RT) was .24mSv/person. If crew members make 3 trips per month (KJFK-ZBAA) exposure would be .72 mSv per month or 8.64 mSv/per year. This is still below the maximum 20 mSv that is limited by the International Council of Radiation Protection. The ICRP limits the maximum radiation exposure to 100 mSv every five years with the maximum single dose being 50 mSv in any one year.