Originally Posted by
Gurnard
Icing sounds very likely, but what about the possible effect upon instruments if the passenger was not using his phone in "flight safe mode"? Evidently he was busy sending messages indicating that he was uneasy.
I'm an electronic engineer with too many years designing safety related electronic equipment. The effect of modern mobile phones on modern electronic equipment should be negligible.
Pitot static and gyro systems are not even electronic. So old style gauges - airspeed, horizon, altitude, turn coordinator, heading, VSI will be completely unaffected.
Modern GPS/glass cockpit systems will be certified to EMC (electromagnetic compatibility) regulations so *should* also be completely unaffected.
There is always the outside chance of something weird happening, but I would put the real world issues - icing / WX / night / single engine / long stretch of water / winter - as almost certainly the real causes. I would be stunned if EMC had anything to do with this.