March 13, 2019 Alan Walker
The atmospheric conditions at the typical cruising altitude of an airliner are not at all suitable for humans. Cabins are pressurized to regulate air density at those altitudes, but what protects us from the cold? At 30,000 ft., the air temperature may be approximately -47.83 ?. Imagine flying through the sky at that temperature without a cabin or a heating system. It would not work out well. There are several systems utilized by an aircraft that provide heat to the cabin.
Fuel fired heaters are mounted or portable space-heaters that obtain fuel through piping from a fuel tank, or by tapping into an aircraft’s fuel system. There are two fans in a fuel fired heater; the first fan blows air into the combustion chamber to be ignited and the second fan blows warm air into tubing directed towards the inside of an aircraft. Fuel fired heaters require electricity and are compatible with 12-volt and 24-volt electrical systems. Gas heaters need to be vented in order to prevent them from leaking dangerous gases into the cabin.
Exhaust systems may be used as a heat source for the cabin and carburetor, and are used on most light aircraft. However, defective exhaust heating systems have a few associated risks such as carbon monoxide poisoning, a decrease in engine performance, and an increased risk of a fire. Maintenance personnel need to carefully inspect the various components of this system in order to reduce the risk of the assorted dangers.
Combustion heaters are commonly used to heat cabins in larger, more expensive aircraft. Fuel is ignited in a combustion chamber or tube and the air flowing around the tube is heated and directed to the cabin. Carbon monoxide then exits the aircraft through the heater exhaust pipe. It is unlikely for carbon monoxide poisoning to occur in this type of heater. There are safety redundancies that also stop this heater from creating other dangerous situations.
Bleed air heating systems are used on turbine-engine aircraft. Compressor bleed air is transferred to a chamber and is mixed with ambient or recirculated air— the air cools off and is then routed to the cabin for heating. There are many safety features involved in this system including temperature sensors, check valves, and engine sensors.
It’s crucial to follow any original equipment manufacturer (OEM) specifications on maintaining heating systems since they can cause various dangerous situations. The safest heating systems are combustion heaters and bleed air heating systems because of their safety components.
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