767-200 dead APU Battery
 

Hoping my question doesn't reveal any remedial systems knowledge, but I'm curious after recently reporting to a/c with dead APU battery.

Why isn't the system designed to be able to start the APU on ground power?

I have a hunch, but I'd like to hear your ideas.

We accomplished engine start with external air and departed with APU deferred.

Thanks.

0/0
Get into your manuals, and look at what feed directly of (hot bus) the main and APU battery, therein lies the answer.

Right, fire detection and protection.
That was my hunch. Just needed a little confirmation. Thanks.