A Delta Airlines Boeing 747-400, registration N662US performing flight DL-167 from Seattle,WA (USA) to Tokyo Narita (Japan) with 364 people on board, was enroute at FL320 about 220nm northwest of Seattle in Canadian Airspace, when the crew declared emergency reporting both flight management system (FMS) navigation equipments had failed. The aircraft entered a hold south of Vancouver Island (Canada) to dump fuel and returned to Seattle for a safe landing about 2 hours after departure.
The Canadian TSB reported maintenance replaced the #1 FMS. The aircraft returned to service the following day.
The Aviation Herald
Delta Air Lines Boeing 747-400 suffers dual FMS failure
