Answer by Thomas Zerbarini:
The short answer is yes, there are a number of frequencies available to pilots for emergency and urgent situations. It would be bad form to discuss these procedural and security questions on a public forum.
The FAA has published distress procedures in the Airman's Information Manual (AIM) that is accessible to you via:
Funny…they call it the Aeronautical Information Manual now:
Here you will find downloadable PDF files for your review. It's a lot of information; but, essential knowledge for all pilots.