Question for jumbo experts......
What difference does it make with APU/Engine air via pack being supplied compared with an external condtioned air source?
Particularly interested in how equipment cooling differs.
Background is that we had a couple of defects - Equip Cooling supply fan u/s and APU u/s. Our paperwork indicted that on the ground with high OAT we had to supply pack air for equipment cooling purposes. With the APU u/s, some people reckoned that an engine would have to be run, others reckoned that ground conditioning would do an adaquate job others
Any thoughts....
T'bug