What makes you think a notice from the Flight Data Center is inherently regulatory? Everything in a NOTAM that is regulatory will have a primary source backing it up (i.e. FAA regulation or statute.) So you need to locate the primary source. The NOTAM isn't primary. FDC can't make up a regulatory requirement like that on its own because it would violate statutory requirements on how regulations are to be created.Palmpilot said:"FDC 4/4386 FDC SPECIAL NOTICE...
NATIONAL AIRSPACE SYSTEM INTERCEPT PROCEDURES. AVIATORS SHALL REVIEW THE FEDERAL AVIATION ADMINISTRATION AERONAUTICAL INFORMATION MANUAL (AIM) FOR INTERCEPTION PROCEDURES, CHAPTER 5, SECTION 6, PARAGRAPH 5-6-2. ALL AIRCRAFT OPERATING IN UNITED STATES NATIONAL AIRSPACE, IF CAPABLE, SHALL MAINTAIN A LISTENING WATCH ON VHF GUARD 121.5 OR UHF 243.0. IF AN AIRCRAFT IS INTERCEPTED BY U.S. MILITARY AIRCRAFT AND FLARES ARE DISPENSED, THE FOLLOWING PROCEDURES ARE TO BE FOLLOWED: FOLLOW THE INTERCEPT'S VISUAL SIGNALS, CONTACT AIR TRAFFIC CONTROL IMMEDIATELY ON THE LOCAL FREQUENCY OR ON VHF GUARD 121.5 OR UHF GUARD 243.0, AND COMPLY WITH THE INSTRUCTIONS GIVEN BY THE INTERCEPTING AIRCRAFT INCLUDING VISUAL SIGNALS IF UNABLE RADIO CONTACT. BE ADVISED THAT NONCOMPLIANCE MAY RESULT IN THE USE OF FORCE." [emhasis added]
Note the use of the word "shall." The only exception appears to be if the aircraft does not have the capability. For example, I assume that an aircraft with only one radio would not be required to monitor 121.5 if that radio were needed for another purpose.