[Mamzelle]

refused to converse by radio?

Now, that's ominous...

[ARCADIA]

refused to converse by radio? Now, that's ominous...

Not at all...he was probably just tuned to the wrong frequency.

Small airplanes are not like airliners. They have only very basic instrumentation and the pilots are often inexperienced. The guy probably had a gyro compass, a radio direction finder, a radio and a paper chart. It is not a very sophisticated system. He is flying VFR, is not in direct radio contact with any flight control center, and it is easy to go astray.

[Rio]

Military intercept procedures are clear and are known to all licensed pilots. Radio contact is not required.

http://www.aopa.org/whatsnew/newsitems/2001/010918intercept.html