Some interesting and useful points made here about this idea of a simple check on the ground for mobile phone interference before using it in the air. From what’s said here my idea of a few simple ground checks in the cockpit is not sufficient on its own. These are a good first step but there are also some general guidelines/principles or perhaps a code of practice for the use of the phone in the air needed as well. This would be to cater for recommendations such as turn the phone off for an ILS approach in IMC, or if tuning into a weak VOR or DME then turn of the mobile to ensure maximum receiver sensitivity, or even students should not text until the aircraft is stationary in case they get thrown out of a moving aircraft by an enraged instructor.