We did airstart 90% of the time in the 73 because of shoddy equipment.
If it’s -25C then well I guess your warming it up from -52C cold soak to -25C.
I suspect this is one of those technique-y things to minimize the thermal stress and stretch out the life of the APU.
Nothing in the MX manual that I have access to and nothing in the FOM except “start APU”.
There are a lot of home grown techniques that make sense but I’m not sure this is one of them.
is it a feel good or does it actually make a difference.