Spooky 2,
"Don't believe there is any requirement to notify anyone when your going to dump fuel, Probably a good idea, but not a requirement.."
Para. 6-3-5. of the FAA's Airman's Information Manual:
Fuel Dumping- Should it become necessary to dump fuel, the pilot should immediately advise ATC. Upon receipt of information that an aircraft will dump fuel, ATC will broadcast or cause to be broadcast immediately and every 3 minutes thereafter the following on appropriate ATC and FSS radio frequencies:
EXAMPLE-
Attention all aircraft - fuel dumping in progress over - (location) at (altitude) by (type aircraft) (flight direction).
- Upon receipt of such a broadcast, pilots of aircraft affected, which are not on IFR flight plans or special VFR clearances, should clear the area specified in the advisory. Aircraft on IFR flight plans or special VFR clearances will be provided specific separation by ATC. At the termination of the fuel dumping operation, pilots should advise ATC. Upon receipt of such information, ATC will issue, on the appropriate frequencies, the following:
EXAMPLE-
ATTENTION ALL AIRCRAFT - FUEL DUMPING BY - (type aircraft) - TERMINATED.
Yes, the term "should" is used (because you wouldn't want to mandate that a crew make that call to ATC if it had more important matters to attend to), but clearly the intent is to advise them - wouldn't you want to know if you were operating on the same route, 1,000' below and about a half-mile in trail?