[ThunderSleeps]

Wouldn’t they use APUs or maybe turn one engine at idle? (rather than 2, 3, or 4) pushing...

You may be right about the AC though. I *think* APUs only provide power/hydraulics for instrumentation and controls. Climate control may have to wait for the main engines.

[USNBandit]

I think you can run an air pack on the APU, but you also have lots of checks to run on the way to the runway.

A couple years ago American started a fuel saving initiative, where dispatchers loaded less fuel so they weren't ferrying fuel. Pilots taxied on one engine, called ahead to gates to have AC and electrical power ready. They save $97 million in one quarter. The next day the company distributed $97 million in bonuses to executives.

[saganite]

APU’s nowadays provide air as well as electrics. No hydraulic power though. There are electrically operated hydraulic pumps that do provide hydraulic power though and since the APU would provide the electricity to run them they would depend on APU power until the engines are running. Of course, if the APU craps out!

Hmm, I’m wondering if these tugs would provide electric power through an umbilical. I didn’t go to the link and read the article but it’s possible!