Overheard Emergencies.
Please educate me in the ways of US airspace.
There is a longer story behind this question - that we can get to later - but let's say you are wombling through the skies and one of your radios is tuned to 121.5 (guard!!).
Scenario 1 - you hear an aircraft calling for assistance...but it receives no response from any ATC unit.
Scenario 2 - you hear an ELT suddenly start transmitting its siren squeak.
What would/should you do in either instance??