Over in Ireland, they have a back-up plan in case an aircraft's radio goes down? They use a mobile phone instead. To text message the pilot and guide him/her in.
That's not as crazy as it first sounds, as Kerry and Cork air traffic controllers fell foul of the 35 kilometre maximum range of GSM voice channels and the voice calls started collapsing.
The reason for this is that, unknown to many, GSM radio channels have up to eight slots for the same number of voice calls to drop their radio data packets into.
If you go beyond 35KM, the signal doesn't have enough time to traverse the base station/mobile/base station complete cycle, and the call conks out.
Not so with text messages, which can carry further owing to their use of the GSM control channels.
I noticed this a few years back on Newquay beach (which then had patchy GSM coverage owing to the cliffs) and received a text message from an Irish GSM network whose base station was at least 60KM away.
When the voice call dropped, the quick-thinking controller in Cork then switched to texting in the hope of staying in contact and, sure enough (begorrah) the novel approach worked.
Check out more on this mobile phone fun here...