It doesn't get used too often, but it can be used for a variety of reasons, including but not limited to:
If ATC want to speak 'off air' (not on one of the regular busy frequencies) to a pilot about an issue, for example maybe something about their flight plan that might take a bit of discussion to work out;
When start clearances are required if there's extensive delays because of poor weather like thunderstorms, or like today when single runway ops are in use and they want to keep the taxiway system free as much as possible to avoid congestion;
If there's an open microphone that's clogging up one of the normal frequencies then ATC will go to 127.6 until the culprit can be found or until it clears itself up.
I hope this helps.
Cheers
__________________
I am always hungry for a DoG Steak! :-)
|