B777-200 CAPTAIN SUSPECTS MAINT OF FALSIFYING ACFT MAINT RECORDS REGARDING A CHRONIC POTABLE WATER SYSTEM FAULT TO MAKE IT ACCEPTABLE FOR A LONG RANGE TRANSATLANTIC FLT. SUPPOSEDLY REPAIRED SYSTEM ONCE AGAIN FAILS ENROUTE.

Narrative

PRIOR TO GETTING TO THE ARPT; I RECEIVED A CALL FROM THE CHIEF PLT AND THE DUTY MGR ON DUTY AT THE TIME. I WAS ADVISED THAT THE CAPT ON THE FLT TURNED DOWN THE ACFT AND IT WAS NOW ASSIGNED TO MY ZZZ FLT. I TOLD THE DUTY MGR THAT I WOULD NEED MORE INFO AND WOULD CALL HIM BACK AFTER I ARRIVED AT FLT OPS. WHEN I ARRIVED; I CALLED THE OPS SUPVR AND THE MAINT SUPVR. THE ISSUE WITH THE ACFT WAS AN INTERMITTENT GAUGE/SENSOR ON THE POTABLE WATER SYS. THIS PROB WAS CHRONIC FOR ABOUT THE LAST WK. WHEN THE GAUGE/SENSOR FAILED TO ZERO; IT WOULD SHUT DOWN THE WATER FOR THE WHOLE ACFT. I WAS TOLD THAT THE SENSOR NEEDED TO BE REPLACED AND THEY DID NOT HAVE A NEW ONE IN STOCK. THEY COULD; HOWEVER; TAKE ONE FROM ANOTHER ACFT AND IT WOULD TAKE ABOUT 8 HRS FOR THE FIX. THIS IS THE SAME INFO THAT WAS GIVEN TO THE PREVIOUS CAPT. I CALLED THE DUTY MGR BACK AND I WAS ASKED HOW I FELT ABOUT TAKING AN ACFT WITH THE POTABLE WATER SYS INOP. I DID NOT FEEL IT WAS SANITARY TO TAKE A 12 HR FLT WITH TOILETS THAT WOULD ONLY DRY FLUSH. FROM AN OPERATIONAL STANDPOINT; IT WOULD ALSO BE A BAD DECISION. EVEN IF I WOULD TAKE IT; IT IS VERY LIKELY THAT THE OUTBOUND CAPT WOULD REFUSE THE ACFT IN ZZZ1 CREATING ANOTHER PROB THERE. I DECIDED THAT IT SHOULD BE FIXED. I ALSO MENTIONED THAT IT COULD BE SENT TO ZZZ2; A 6 HR FLT INSTEAD OF 12 HRS. I TOLD THE DUTY MGR AND MAINT THAT THE ACFT WOULD HAVE TO BE FIXED IF I WAS TO TAKE IT TO ZZZ1. ABOUT 1 HR LATER; I CALLED THE MAINT SUPVR AND WAS TOLD THAT THEY FOUND A 'MIRACLE FIX.' I QUESTIONED HIM FURTHER; AND WAS TOLD THAT THEY WERE ABLE TO RECALIBRATE THE SENSORS AND THE ACFT WAS FIXED AND READY TO GO. THIS WAS CONTRARY TO WHAT I HAD BEEN TOLD BEFORE. ABOUT 5 HRS INTO THE FLT; THE SENSORS FAILED AND THE POTABLE WATER GAUGE SHOWED 1 GALLON. FORTUNATELY; IT DID NOT FALL TO ZERO AND WE WERE ABLE TO HAVE WATER THE REST OF THE FLT. WE WERE FORTUNATE. I THINK IT IS CLR THAT THE ITEM WAS NOT FIXED. IT SEEMS LIKE IT WAS A WAY TO GET US OUT OF TOWN WITHOUT A REAL FIX.