Gas turbine engine having a heat exchanger arrangement for heating or cooling a fuel

An engine, comprising:

• an air intake arrangement configured to receive air;
• a fuel tank configured to store a fuel for being supplied to an air-breathing combustion chamber;
• a heat exchanger arrangement arranged downstream of the air intake arrangement and configured to cool the air by providing for heat exchange between the air and a heat transfer medium;
• and
• a compressor arranged downstream of the heat exchanger arrangement and configured to supply compressed air to the air-breathing combustion chamber for the combustion of the air and the fuel;
• wherein the heat exchanger arrangement is configured to be selectively operated in a first operating mode which corresponds with a first operating flight speed of the engine, and a second operating mode which corresponds with a second operating flight speed of the engine that is lower than the first operating flight speed of the engine;
• wherein in the first operating mode of the heat exchanger arrangement, the heat transfer medium is configured to heat the fuel before the fuel is delivered to the air-breathing combustion chamber;
• and
• wherein in the second operating mode of the heat exchanger arrangement, the heat transfer medium is configured to cool the fuel before the fuel is delivered to the air-breathing combustion chamber.