Air carrier Dispatcher reported airborne flight; which was transporting Class 1 Hazmat cargo; experienced a hydraulic malfunction during cruise. After much troubleshooting and collaborating with multiple departments the flight continued to destination.

Narrative

This was filed under Aircraft X. At approximately XB00 I saw a message from the crew stating Aircraft X- XXXXXX/DA ZZZ2/DS ZZZZ/FOB 102000/FTX SHOWING 6.0 ON SYS 3AND GOING DOWN I contacted Maintenance Control and asked what the issue was with the flight. Maintenance Control stated they were losing hydraulic fluid in #3 hyd. I went to inform the Duty Officer and let service recovery know. XB09 SATCOM from crew and conferenced Maintenance Control in. The hydraulic 3 pump was losing quantity at a high rate and we went through the QRH and maintenance explained that they would not have hydraulic 3 but could still deploy gear manually. I confirmed with crew that the QRH did not state land at nearest suitable and they concurred but stated with cargo on board they may not feel comfortable if they did not land at nearest suitable. This flight had 47.7kg of class 1 explosives on board. Rockets with burst munitions. They had already lost 2.5 gallons of hydraulic fluid from 3 in the 4 hours of flight time and would only have 2 gallons left with 5 hours remaining to fly. Were concerned they were losing it at too high a rate to make it the rest of the way to destination. Crew opted to turn back to ZZZ1; with the intent of [priority handling]; FL370. If it stabilized in the 464 miles back to ZZZ1 they would continue on to ZZZ. Shortly after we added MD11 pilot to the conversation. Pilot instructed crew to turn off eng driven pumps l/r for #3 and the reversable motor pumps for #3. The flight turned to approximately Location back to ZZZ1 fl370 while we were talking to the pilot. While talking with pilot decided to continue to ZZZ the crew [requested priority handling] and was given direct to ZZZZZ ZZZZZ1 on the ZZZZZ2 arrival into ZZZ. Many coworkers stepped in to make contact with ZZZ1; ZZZ. Helping set up with Tower the route on ground. ZZZ Center watch desk helped with land Runway XR for arrival; left turn [taxiway] 1; left onto [taxiway] 2 waiting for tug at 1. They were determining which taxi route to give them as they need to go to ZZZ2 and the haz cargo ramp to remove the freight they would not be let back on our ramp. Call back with another issue will temp in hydraulic reservoir going up even though no pump should be running. Maintenance Control and pilot agreed this could be the pump did not shut all the way off but the fail safe was when the pump got too hot it would send an overheat EICAS and shut down automatically. Then manual would be required. Crew asked for info on what to expect and I said I would send that all on ACARS. Cause: hydraulic 3 failure Suggestions: A few items of note; Maintenance Control was watching the Aircraft Health Management (AHM) Aircraft help monitoring system and received 2 alerts one at XA55 and one at XA56. When they received the alerts they sent message straight to flight; when I saw the report was my first indication. The knowledge of the pilot in aiding the crew was invaluable however; I was given the sense they were trying to persuade the crew to turn back and go to their original destination of ZZZZ. Continually asking why the crew chose to turn back. I finally stepped in and informed of the payload on the aircraft and they still tried to persuade. I ask their help and explained where they went was between the Captain and the Dispatcher and ultimately the captain. Maintenance Control spoke up and said neither ZZZZ or ZZZ1 were very good options for Maintenance the flights would be sitting for days awaiting repair. I said I understood; Dispatch would say ZZZ was better than ZZZ1 for many reasons but wanted to inform crew of options. When I told the crew after the second call that I would send them what was being coordinated as we spoke pilot stepped in trying to tell crew what they could do and likely not do when on ground. I reiterated I would be sure they received the information and confirmed they [requested priority handling] and would inbound to ZZZ.