Ron Natalie wrote:

There's no specific requirement for W&B paperwork in the regs despite
what your flight instructor told you.

I have found 23.1583, which states that maximum weight and center of gravity
limits are part of the aircraft manual, and 23.1519 which states that
weight and CG limits are a part of operating limitations.

But what's the documentation requirement for equipment changes which alter
one or more of these factors? 23.21 discusses this for type certification,
but not for upgrades.

I've found nothing which discusses that. I'd have expected something in
part 43, but I'm not seeing it.

- Andrew