Drain system for an aircraft

A drain system for an aircraft, comprising:

• a mast arranged and operable to perform at least one of:
• (1) drawing ram air into the aircraft, and (2) draining liquids or gases from the aircraft, the mast further being operable to deliver the ram air to a thermal or electrochemical process being carried out on board the aircraft;
• a change-over valve operable to deliver cabin air to the thermal or electrochemical process alternatively or additionally to the ram air;
• an air compressor operable to compress air to be delivered to the thermal or electrochemical process;
• a pressure control unit operable to regulate the pressure of the air to be delivered to the thermal or electrochemical process;
• and
• a tubing containing a coolant;
• the tubing being positioned and operable to conduct a portion of the heat generated by the coolant to heat the mast;
• the tubing being further positioned and operable to deliver the coolant to the thermal or electrochemical process;
• and
• the tubing being further positioned and operable to conduct a portion of the heat generated by the thermal or electrochemical process to heat the coolant.