B767-300 and 300 ER
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe
Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft; Human Factors
On departure both MCDC's frozen; unable to manipulate any NAV functions via FMS. Went into holding; through company maintenance coordination reset circuit breakers. Returned [to departure airport]; no assistance needed on ground. Uneventful return.
Shortly after the aircraft departed both FMC's froze. Flight crew initially sent an ACARS then called via SATCOM. Initial communication was good. When I tried to conference in [Maintenance] and Duty Officer conference button on the phone was not there; then connection was lost. Tried a couple times to regain SATCOM connection but was unable.Flight crew heard the SATCOM call but unable to connect.[One] thing which I found of issue during the call was the conference button would not be available during all phases of the call.
B767 Captain and Dispatcher reported the flight returned to departure airport after experiencing dual FMC failure.