Nitrogen enriched air supply system and aircraft

A nitrogen enriched air supply system which produces nitrogen enriched air that is enriched with nitrogen upon supply of source gas during a flight of an aircraft through an ascent phase, a cruising phase, and a descent phase, and supplies the nitrogen enriched air to a fuel tank of the aircraft, the system comprising:

• a main pipe through which the source gas flows;
• an air separation module that separates oxygen and nitrogen in the source gas;
• a temperature regulation mechanism comprising a bypass pipe for the main pipe, a temperature sensor, and cooling means that cools the source gas passing through the bypass pipe or the main pipe, the temperature regulation mechanism regulating a temperature of the source gas supplied to the air separation module, a temperature of the source gas in the bypass pipe, and an amount of the source gas flowing into the bypass pipe;
• and
• a flow regulation valve that regulates the amount of the source gas flowing through the bypass pipe and the main pipe according to instructions from the temperature regulation mechanism,
• wherein, in at least a part of a flight period through the ascent phase and the cruising phase, the temperature regulation mechanism sets the temperature of the source gas to below a temperature of the source gas in the descent phase, and
• wherein the flow regulation valve is placed upstream at a branch point of the bypass pipe and the main pipe.