Effects of Operating Jet Fuels Below the Specification Freeze Point Temperature Limit

摘要

In the United States, commercial jet aircraft operations are currently limited to measured wing tank fuel temperatures that are greater than 3DGC above the fuel specification freeze point. In recent years, long-duration polar routes have been open, which result in fuel being subjected to lower temperatures for longer periods. When the measured in-tank fuel temperature approaches these low-temperature limits, pilots are forced to modify flight path, altitude, and/or airspeed to raise these temperatures. As many fuel samples have freeze points that are significantly below the fuel specification, airlines would like to change the low-temperature operational limit to reflect the measured freeze point of the particular fuel sample in the aircraft fuel tank, rather than the specification freeze point. This could minimize unnecessary flight path, altitude, and/or airspeed alterations with significant cost savings. This report summarizes the study of the effect of low temperatures on jet fuel properties and fuel system operation.