The CAO argument is interesting.
It says you cannot take off at a weight greater than that determined from the P charts. But what if you cannot determine a weight?
You might not be able to show compliance, but can CASA prove, based on the same (lack of) performance information that the plane wouldn't perform?
Is there a specific regulation that explicitly states that you cannot operate outside the P chart figures?
Im just being a little bit of an advocate for the devil; I'm not necessarily brave enough to take on the potential battle.
My other question is- why only now does CASA say that you cannot operate when the temp is outside the P chart temperature? They've been in existence for decades, and it's not a new idea.