BHenderson
Sorry for nitpicking but the ANO actually says
An operator shall not permit a helicopter rotor to be turned under power for the
purpose of making a flight unless there is a person at the controls entitled in
accordance with article 26 of this Order to act as pilot-in-command of the helicopter.
There is a common misconception that it says what you posted. Whilst it is similar, its not quite the same. If the purpose is not to go flying then seems it is still acceptable for students to start helicopters. Also allows non-pilot engineers to carry out ground runs.
I am sure that in this thread the intention would be to then go flying, so the ANO def would still apply. Knowing where to find some of the minutae can be handy sometimes.
I am not trying to be an arse, just point something out.
I can't express an opinion as to whether its sensible to leave a helicopter rotors running, as I am UK based and we don't tend to do it. But the rest of the world seems to manage quite happily without an inordinate number of accidents.
What other countries than Australia and Canada, and I think the USA is it a normal practice ?
Gary