extreme heating increase of its lubricant in relation to the available air cooling capability on the ground on a hot day the generator in this circumstance will typically supply its greatest load and generate the most heat in its lubricant in doing so as the aircraft interior is cooled for example by electrically operated air conditioning and has its lights and instruments also operating to thereby provide some maximum electrical load in this situation the engine will be just idling so that there will not be much of an engine fan secondary airstream to be used by the generator lubrication system air and oil heat exchanger to cool the lubricant here too the lubrication system at this extreme condition will need to limit the temperature of its lubricant to not exceed some value typically 200 u00b0 f however the aircraft taking off greatly increases the engine fan secondary airstream so that even though the generator heat output will increase somewhat compared to being on the ground with the engine idling the cooling capacity of the generator air cooled oil and air heat exchanger is increased much more thereby also leaving extra cooling capacity in this lubrication system in this situation in most preflight and flight situations both generator lubrication system 10 and engine lubrication system 20 of fig1 and 2 would be able to have.