MD11 flight crew and the dispatcher involved report on the decision to return to yssy when the fire ...

Narrative:

We were an hour and a half into our flight. I (the rfo) went back to take first rest period. I saw the FSS (fire suppression system) panel was continuously cycling from normal to off (blank) to a red 'fault argon pressure' alert. I snapped a picture of it to show the rest of the crew. We began a conversation about the dg (dangerous goods) we were carrying and having no back up protection available. We knew the FSS was; at best; not working. At worst; it might be leaking argon into the ship...we could not know its status. It was decided that it was best to return to syd rather than risk the lives of the crew to proceed for another 6 hours over water with nowhere to land and with dg aboard. The dg included; not just lithium batteries; but flammable solid; liquid; gas; corrosive and more. The captain acar'sed ops and maintenance control and also communicated by satcom. Maintenance control reviewed the FSS history of the ship and found none. The MEL directed the crew to review the fom. The fom indicated that without operational FSS on board the dg could be place in a can and the old system be reactivated or the dg could be removed from the aircraft. We had dg on a pallet with no way to fight a fire. This was unsafe at best. The issue was this: without an operable FSS; either no dg can be carried aboard the a/c or the old system of a dg container and hoses must be in place. We had neither. The captain elected for safety and legality. We considered ybbn as it was closer; but elected syd. The first officer had given ATC a heads up that we likely would return to syd. We dumped about 42;000 lbs of fuel at FL300 to reduce to below mlw. The first officer flew an uneventful approach and landing to R34L syd. (Maintenance also took photos of the malfunctioning system; as they had not seen it before either. Maintenance also confirmed that it was not safe to fly with the current dg configuration)FSS failed while carrying dg. The fault light (argon pressure) came on and off continuously. We had no way of knowing based on the fault light what had failed and what still worked. The argon gas may have leaked out. The system may have been inop. There was simply no way of determining the level of the failure. This led us to believe that we may not have any ability to detect or fight any type of fire in the cargo area.

Original NASA ASRS Text

Title: MD11 flight crew and the Dispatcher involved report on the decision to return to YSSY when the fire suppression system faults enroute with dangerous goods aboard.

Narrative: We were an hour and a half into our flight. I (the RFO) went back to take first rest period. I saw the FSS (Fire Suppression System) panel was continuously cycling from normal to off (blank) to a red 'FAULT argon pressure' alert. I snapped a picture of it to show the rest of the crew. We began a conversation about the DG (Dangerous Goods) we were carrying and having no back up protection available. We knew the FSS was; at best; not working. At worst; it might be leaking argon into the ship...we could not know its status. It was decided that it was best to return to SYD rather than risk the lives of the crew to proceed for another 6 hours over water with nowhere to land and with DG aboard. The DG included; not just lithium batteries; but flammable solid; liquid; gas; corrosive and more. The Captain ACAR'sed ops and Maintenance Control and also communicated by satcom. Maintenance Control reviewed the FSS history of the ship and found none. The MEL directed the crew to review the FOM. The FOM indicated that without Operational FSS on board the DG could be place in a can and the old system be reactivated or the DG could be removed from the Aircraft. We had DG on a pallet with no way to fight a fire. This was unsafe at best. The issue was this: without an operable FSS; either no DG can be carried aboard the a/c or the old system of a DG container and hoses must be in place. We had neither. The Captain elected for Safety and legality. We considered YBBN as it was closer; but elected SYD. The FO had given ATC a heads up that we likely would return to SYD. We dumped about 42;000 lbs of fuel at FL300 to reduce to below MLW. The FO flew an uneventful approach and landing to R34L SYD. (Maintenance also took photos of the malfunctioning system; as they had not seen it before either. Maintenance also confirmed that it was not safe to fly with the current DG configuration)FSS failed while carrying DG. The fault light (Argon Pressure) came on and off continuously. We had no way of knowing based on the fault light what had failed and what still worked. The Argon gas may have leaked out. The system may have been inop. There was simply no way of determining the level of the failure. This led us to believe that we may not have any ability to detect or fight any type of fire in the cargo area.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1315354
Time
Date	201512
Local Time Of Day	1801-2400
Place
Locale Reference	YBBB.ARTCC
State Reference	FO
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	MD-11
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Fire Extinguishing Indication System
Person 1
Function	Relief Pilot
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe

MD11 flight crew and the dispatcher involved report on the decision to return to yssy when the fire suppression system faults enroute with dangerous goods aboard.