System for temperature and actuation control and method of controlling fluid temperatures in an aircraft

A system for fluid temperature control and actuation control for an aircraft engine fueled by dual fuels, comprising:

• a first fuel system having a first fuel tank fluidly coupled to the engine;
• a second fuel system having a second fuel tank fluidly coupled to the engine, with the second fuel being different from the first fuel and having a different temperature than the first fuel;
• a fuel distribution unit (FDU) fluidly coupled to the first fuel tank of the first fuel system and configured to distribute the first fuel from the first fuel tank to the engine;
• and
• a fuel-to-fuel cooler (FFC) fluidly coupled with the first fuel system and the second fuel system and configured to transfer heat between the first fuel in the first fuel system and the second fuel in the second fuel system,
• wherein said second fuel is liquefied natural gas (LNG).