B767-300 and 300 ER
Aircraft Equipment Problem Critical; Inflight Event / Encounter Weather / Turbulence
Flight Crew Returned To Departure Airport; General Declared Emergency; General Maintenance Action
Aircraft; Weather
[We had a] weather radar failure with good test indications. [We were] unable to continue to destination due to weather enroute. Received clearance to [departure airport]; received clearance to dump fuel and declared emergency for anticipated overweight landing. Dumping began at FL290 and ended approaching [airport] at 6;000 FT. Approach and landing normal with 25 flaps. ARFF inspected brakes and gear before taxi to gate. ARFF escorted aircraft to gate and provided fans to minimize brake temperatures. Good coordination between Dispatch; ATC; ARFF and [airport].
Reporter stated a B767-300 had a loss of weather radar; and with weather forecast enroute was unable to continue. Emergency was declared for overweight landing and flight returned to departure airport.