B777 Undifferentiated or Other Model
Flight Crew Last 90 Days 188; Flight Crew Total 14623; Flight Crew Type 769
Distraction; Confusion; Troubleshooting
Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance; Flight Deck / Cabin / Aircraft Event Other / Unknown
Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Overcame Equipment Problem
Aircraft; Procedure
During cruise flight; Flight Attendant called and asked about the 'bang' sound during take-off.  Both pilots were unaware of the sound.  Approx. 1 hour later; she called and said she heard it again under the floor; mid galley.  We contacted dispatch with this info and were told they believe it's a cargo pallet.  The called on Sat Phone and we discussed the problem.  They advised.  We told ZZZ to give us the longest Runway.  Upon landing; I used very little breaking to slow down (so the pallet would not shift further) and exited the Runway at the very end.  Landing was uneventful.After parking at the gate; a ramp personnel came to the cockpit and told me that not only was the pallet not tied-down; it also was not locked into place.  He said it was moving around freely.
A 777 flight crew was alerted by the flight attendants of unusual noises heard emanating from the cargo area. A loose pallet was suspected and a successful precautionary landing was made using minimal braking.