keep mobiles off, unless permitted by the local licencing avition authority, commander/Captain of the aircraft you're on
I'd err on the side of caution and say that the licensing authority should know better, being permitted because the Captain said so probably wouldn't look good after an accident resulting from distraction/loss of SA because one of the crew was on the phone..... for instance... what if your Capt was the one mentioned by HairDryer...? Does that then make it ok to take calls on approach? Where will it end? People surfing the landing? Smoking in the lavs?
My belief is the only way you can keep things operating safely is to obey the rules
and stick to them consistently until you are told otherwise or the rule is changed. We haven't got where we are in Aus aviation by breaking all the rules...
(Edited for crap typos)