Narrative:

We had an uneventful takeoff and climb to cruise. When the seatbelt sign was turned off; the flight attendants called to say the potable water was inoperative. We have no procedures airborne to fix that problem and told them there was nothing we could do until we got on the ground in ZZZ. We were cruising at FL380; past the fix ZZZZ in the middle of ocean when the aircraft shuddered as if we ran through some wake turbulence or jet wash. All instruments were indicating normal and the plane appeared to fly normally. The flight attendants called and asked about the disturbance. We asked if they had just moved a beverage cart as the sound was similar to rough handling of a beverage cart. They said they had not. With everything appearing normal; we assumed it was shifting cargo or a pocket of turbulence. The first officer made a PA and told the passenger the disturbance was turbulence. The flight continued on with an uneventful descent; approach; landing; and taxi in to the gate. Before the first officer could do a preflight for the next flight; a non-revenue pilot told us she saw a piece of metal torn on the slat. The first officer and I went out to the right wing and saw a vertical tear in the aluminum of the inboard right slat. The damage was clean; with no bird debris. The ZZZ ground crew told us the potable water door was improperly secured; jammed shut. On our preflight inspection out of ZZZZ; the potable water door was secured and not leaking. There are no controls for the potable water in the cockpit. The potable water door; fuselage and slat cannot be seen from the cockpit. A ZZZ ramp agent was able to call and I was able to use his phone to relay the information. The representative wanted us to look over the entire airplane again to check for additional damage. We did that and the slat was the only damage. ZZZZ airport wanted our gate so the aircraft was moved. The first officer and I were in the cockpit coordinating the move with ground control. We got back to our original gate; met with our flight attendants; and were informed the company wanted us to layover. Callback conversation with reporter revealed the following information: reporter stated the potable water tank was serviced prior to departure. Ground crew at arrival station said the water service panel was leaking and service valves not properly closed. Someone had managed to jam the door panel shut; but water was still leaking out. Reporter stated the belief is; the leaking water panel developed an ice chunk that separated in cruise and struck the slat causing the vertical tear.

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Original NASA ASRS Text

Title: A B757 PILOT IS INFORMED BY FLT ATTENDANT THE CABIN POTABLE WATER WAS INOPERATIVE. ACFT SHUDDERED AT CRUISE ALTITUDE. LATER FOUND THE RIGHT INBOARD SLAT WITH VERTICAL TEAR AND WATER PANEL DOOR JAMMED SHUT.

Narrative: WE HAD AN UNEVENTFUL TKOF AND CLB TO CRUISE. WHEN THE SEATBELT SIGN WAS TURNED OFF; THE FLT ATTENDANTS CALLED TO SAY THE POTABLE WATER WAS INOP. WE HAVE NO PROCS AIRBORNE TO FIX THAT PROB AND TOLD THEM THERE WAS NOTHING WE COULD DO UNTIL WE GOT ON THE GND IN ZZZ. WE WERE CRUISING AT FL380; PAST THE FIX ZZZZ IN THE MIDDLE OF OCEAN WHEN THE ACFT SHUDDERED AS IF WE RAN THROUGH SOME WAKE TURB OR JET WASH. ALL INSTS WERE INDICATING NORMAL AND THE PLANE APPEARED TO FLY NORMALLY. THE FLT ATTENDANTS CALLED AND ASKED ABOUT THE DISTURBANCE. WE ASKED IF THEY HAD JUST MOVED A BEVERAGE CART AS THE SOUND WAS SIMILAR TO ROUGH HANDLING OF A BEVERAGE CART. THEY SAID THEY HAD NOT. WITH EVERYTHING APPEARING NORMAL; WE ASSUMED IT WAS SHIFTING CARGO OR A POCKET OF TURB. THE FO MADE A PA AND TOLD THE PAX THE DISTURBANCE WAS TURB. THE FLT CONTINUED ON WITH AN UNEVENTFUL DSCNT; APCH; LNDG; AND TAXI IN TO THE GATE. BEFORE THE FO COULD DO A PREFLT FOR THE NEXT FLT; A NON-REVENUE PLT TOLD US SHE SAW A PIECE OF METAL TORN ON THE SLAT. THE FO AND I WENT OUT TO THE R WING AND SAW A VERT TEAR IN THE ALUMINUM OF THE INBOARD R SLAT. THE DAMAGE WAS CLEAN; WITH NO BIRD DEBRIS. THE ZZZ GND CREW TOLD US THE POTABLE WATER DOOR WAS IMPROPERLY SECURED; JAMMED SHUT. ON OUR PREFLT INSPECTION OUT OF ZZZZ; THE POTABLE WATER DOOR WAS SECURED AND NOT LEAKING. THERE ARE NO CTLS FOR THE POTABLE WATER IN THE COCKPIT. THE POTABLE WATER DOOR; FUSELAGE AND SLAT CANNOT BE SEEN FROM THE COCKPIT. A ZZZ RAMP AGENT WAS ABLE TO CALL AND I WAS ABLE TO USE HIS PHONE TO RELAY THE INFO. THE REPRESENTATIVE WANTED US TO LOOK OVER THE ENTIRE AIRPLANE AGAIN TO CHK FOR ADDITIONAL DAMAGE. WE DID THAT AND THE SLAT WAS THE ONLY DAMAGE. ZZZZ ARPT WANTED OUR GATE SO THE ACFT WAS MOVED. THE FO AND I WERE IN THE COCKPIT COORDINATING THE MOVE WITH GND CTL. WE GOT BACK TO OUR ORIGINAL GATE; MET WITH OUR FLT ATTENDANTS; AND WERE INFORMED THE COMPANY WANTED US TO LAYOVER. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THE POTABLE WATER TANK WAS SERVICED PRIOR TO DEPARTURE. GROUND CREW AT ARRIVAL STATION SAID THE WATER SERVICE PANEL WAS LEAKING AND SERVICE VALVES NOT PROPERLY CLOSED. SOMEONE HAD MANAGED TO JAM THE DOOR PANEL SHUT; BUT WATER WAS STILL LEAKING OUT. REPORTER STATED THE BELIEF IS; THE LEAKING WATER PANEL DEVELOPED AN ICE CHUNK THAT SEPARATED IN CRUISE AND STRUCK THE SLAT CAUSING THE VERTICAL TEAR.

Data retrieved from NASA's ASRS site as of May 2009 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.