We all know that every combustion engine (except maybe in rockets), rely on an external air source for combustion. Problem for aircraft is that, the air entering the combustion chamber may not always have the ideal temperature for a healthy combustion.

Cold air usually found at high altitudes for example, is denser than air at sea level. Cold air being denser, requires more fuel otherwise an air-fuel ratio imbalance occurs and the combustion will be erratic. If the combustion in an aircraft engine is erratic, and you know what will happen. So, when the air is colder than optimum temperature, there are two things you ... Read more »