Originally Posted by
Exup
747 classic had issues with cold soak but it wasn’t the APU but the APU Battery that caused the issue, usually due to the fact tha the battery heater mate was not working
No, was definitely the APU. Boeing in conjunction with I think it was Garrett tried to track down the cause. They had a bunch of recommendations which are still relevant today; nominally oil <viscosity> and fuel <flow>, but that doesn’t exclude other things that are still part of the equation such as battery health. Note that it was these types of enquiries (as a result of operator reports) that helped lead to the improved apu of today.
i do agree that the airbii need a little more finesse than the flying pigs, it’s because they are a little more precious... haha
To the other chap asking about the off topic 737ng apu f/f - your mx staff would be able to validate by checking input monitoring and/or their books, but yes, the numbers are in that vicinity. Turn the apu bleed switch off on gnd if not using packs (excluding starting ops, obviously); save a tree or two.