Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 200; Flight Crew Total 20000; Flight Crew Type 9000
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Fuel Issue
Air Traffic Control Issued New Clearance; Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport
Aircraft
I was one of the relief pilots on this flight. Approx. 2 hr's after push back; myself and the other relief pilot was awoken from our required rest. After entering the cockpit we were informed that the First Officer's Air Data Computer (ADC) failed and we were returning. We were informed of what the flying pilots had done and we discussed what else we needed to do. We informed ATC we needed to jettision fuel to land. We were given clearance from ATC to dump fuel. We informed ATC we would be dumping for 20-30 min. We were given holding instructions to dump. At completion of dumping we contacted ATC; and received a clearance to the departure airport. We finished all required check lists and landed uneventfully.
B747 Relief pilot reported being summoned from the bunk room after the flying First Officers ADC fails; about two hours after departure. Fuel is dumped and the flight returned to the departure airport.