I don't know the UAE's GCAA requirement, but coincidentally I am studying for the UK CAA/EASA Air Law exam at the moment for my PPL where I would imagine the the rules will be very similar if not the same, and it reflects my own anecdotal evidence.
It states that one pilot is at the controls at all times, and both pilots at the controls during take-off and landing.
http://www.caa.co.uk/docs/33/cap393.pdf ANO Article 93, section 1, part 10, page 5 if you're really that inclined.
Cheers, Howard