Date: 201511
Location: ZZZZ.ARTCC, FO
Aircraft: B777-200
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Cruise
ATC / advisory: Center ZZZZ
Reporter organization: Air Carrier
Reporter function: Dispatcher
Anomaly: Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew Diverted; Flight Crew Landed As Precaution; General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Ambiguous

Narrative: I received an ACARS msg from one of my flights; indicating a diversion back to Japan. I in turn responded with a confirmation ACARS msg just to make sure what I was seeing was correct. The crew responded with an 'Affirmative' msg that they are indeed diverting; and that they have chosen ZZZZ to divert to.I established voice communication with the flight to discuss diversion options i.e. re-consider diverting to ZZZZ and to divert to planned ETOPS alternate ZZZZ1. The crew and I agreed that ZZZZ1 will be the airport to divert to and land. About that same time; Maintenance Control sent an ACARS to the flight to clarify the warnings they were seeing also; however; they were sending the messages to the wrong tail number and did not know that (I guess). Shortly after; I received a call from a Maintenance Control rep. who expressed that the flight divert to ZZZZ2 so better maintenance could be performed.I discussed this option with the crew; but we both decided that if there was/is an actual fire on the aircraft; that continuing on to an airport further away was 'not' a safe option. ZZZZ1 is where we will go. The crew did advise that they did discharge the extinguisher into the lower aft cargo department.The crew reported a fire warning in the lower aft cargo compartment and that they needed to divert back to Japan.The events that took place happened in an orderly and efficient manner. The flight crew and dispatcher performed their duties in a professional and efficient manner. The one thing that 'may' cause some concern was that Maintenance Control was trying to communicate with the flight at the same time Dispatch was communicating with the flight. The possible situation here would be that the flight crew; in a situation like this are trying to communicate with ATC; and Dispatch; and to have a third party intervene with more communication could be more than necessary.Possible Solution: If Maintenance Control sees a message; it might be best if they contact Dispatch to discuss the message first; then let the dispatcher contact the flight since the dispatcher is responsible for the flight. Maintenance Control would be more than welcome to be conferenced in on the call if they have any questions for the flight. Keep in mind things were happening very quickly and both the crew and the dispatcher were very busy handling the situation to the best of their abilities.




Synopsis: B777 Dispatcher reported one of his flights diverting back to Japan due to a fire warning in the lower aft cargo compartment. Maintenance Control became involved with choosing a divert airport for maintenance considerations; when the nearest suitable airport should have been the only consideration with a fire warning.