.  Expected fuel freeze value and Fuel Freeze Prediction value.

.  Pay attention to the altitudes of the Tropopause and associated OATs. Typically the Tropopause may be as low at 18,000-24,000 ft. over Polar / Siberian routes.

.  Note areas of enroute SAT’s forecast to be -65 or below and the duration.

4.2  Solar Flare Activity The dispatcher is to monitor the solar flare activity bulletins issued from time to time and brief the crew accordingly. In case of unacceptable solar flare activity the flight is to be re-routed via the non polar routes.
4.3  In case of the fuel temperature predicted values are below the freeze values the flight may have to be re-routed via non polar routes.
4.4  In case of non availability of HF communication due to solar flare activity the flight may have to be routed by non polar routes.
Issue I 28.08.2007  Rev. 0

5. Outside Air Temperature (OAT), Fuel Temperature, Fuel Freeze Values
If routed through regions with SATs of -65 C or below, pay particular attention to the Flight Plan Wind Summary for detailed information on the extent and altitude range of the coldest air and review the Fuel Freeze Prediction value data provided in the flight plan package. These values are generated by a software program that takes into account forecast SAT, TAT, fuel upload, flight time, effects of hydraulic fluid cooling lines in the fuel tanks, and other variables to provide a very accurate assessment of the anticipated fuel temperatures throughout the flight. Fuel tank temperature predictions that are below the fuel freeze value for the fuel onboard require alteration of the flight plan to warmer OATs.
Most major airports have fuel distribution systems that preclude the handling of multiple fuel types. Due to safety concerns and airport regulations, it is impractical to upload fuel from trucks to an aircraft the size of the B777. Due to these restrictions we are limited to the type of fuel available at the airport, which in the United States is Jet A.