The Boeing Company
Fuel burn adjustment based on measured lower heating value

Abstract:

An aircraft is provided that includes a fuel storage tank for aviation fuel, and avionics systems interconnected by an avionics bus. The fuel storage tank receives aviation fuel during a fuel uplift for a flight according to a flight plan that includes and depends on a predicted fuel burn determined based on a reference lower heating value (LHV) of the aviation fuel. The avionics systems include temperature and density sensors, and a flight management system (FMS). The temperature and density sensors measure respectively the temperature and density of the aviation fuel. The FMS receives the measurements, estimates an actual LHV that is different from the reference LHV based on the measurements, and determines an adjusted predicted fuel burn for the flight based on the predicted fuel burn and the actual LHV. The FMS displays the adjusted predicted fuel burn and enable adjustment of the flight plan based thereon.