While modern aircraft engines are quite reliable and powerful, they tend to experience more trouble when operating in colder conditions. This is due to the fact that modern engines still rely on the combustion of fuel and air mixtures to generate thrust, and colder conditions can deter the efficiency and startup speed of assemblies as they begin to operate. Because of this, it is common to preheat engines to get them warmed up before flight which can lead to a number of benefits and improvements to flight reliability.