Paxboy, I really don't give a toss about this because I don't want to use a GPS on a commercial airliner, but I have to follow up on your comment...
Thousands of hand-held GPS devices (i.e. not permanent fixtures of an aircraft) are used in thousands of aircraft every day, all around the world. Maybe not in the British Airways or American Airlines of this world, but certainly in both lower-level air carriers and in general aviation in all of its manifestations, from air taxis to single engined light aircraft. If you're seriously suggesting that such devices give rise to a risk to those sectors of aviation, then maybe the operation of such GPS devices should be banned in all aircraft? I suspect that many of the airborne applications for hand-held GPS involve aircraft with far simpler (i.e. old, unsophisticated and thus more susceptable to interference) avionics fit than the modern airliner in which the systems [presumably] have been somewhat more rigourously subjected to testing for suceptability to RF interference.
So, again, if aircraft from third-level airliners down to SEPs are not falling out of the sky or seriously suffering from avionics interference as a result of the use of hand-held GPS whilst in flight (including the aircraft I fly regularly), I'm still mystified as to why it should be an issue on airliners. And, as I said above, logic suggests that if you ban hand-held GPS, you should also ban laptops, iPods and pretty much all other portable electronic devices (my camera even has a capability to transmit wirelessly and not using IR) from use in the cabin.
A