The policies regarding the use of mobile phones seems to vary from airline to airline and it's not always clear. Last week I was berated by fight att. on a Turkish Airlines flight that had arrived in Istanbul for switching on my mobile phone as I was passing her by the exit door. Obviously the engines had been shut down and the door open (I was about 2 metres from the door) She explained it was company policy that phones be turned off while aboard the aircraft, I told her that while I was happy to comply I would have felt more secure if she'd done something about the mobile phones I could hear ringing while the aircraft was taxying, again immediately after takeoff at about 500m and again just seconds before the wheels touched the ground for landing. No response from her.
I was on a Swiss flight the previous week and their announcement on landing in Belgrade was quite specific that phones should not be used until the fasten seat belt sign is off, the engines shut down and the door open.