"We have to test for water content and make sure Fuel System Icing Inhibiters are present to prevent fuel from freezing at high altitudes," said Staff Sgt. Jermey Manning, 2nd LRS fuels laboratory technician. "If there is water in the fuel, at high altitudes it will freeze up the fuel lines, causing the airplane to fall out of the sky."
Read more: http://www.barksdale.af.mil/news/story.asp?id=123461443