Narrative:

Climbing west out of ZZZ and just west of the shoreline at probably 6000 ft MSL, we heard a thump. We discussed it and decided it was a cargo bin that shifted. The purser heard the same thing and felt the same. There were no other indications of any problems. We elected to continue the flight to ZZZZ. After the layover and arriving at ZZZZ operations we noticed the aircraft still on the ramp. We asked operations why. We were told that 2 large panels covering the air conditioning units had been partially torn from the aircraft. This was probably what we heard. I had done the walkaround earlier. I had plenty of time for the walkaround that day and had spent more time than usual looking under the belly. I did not notice anything unusual. Callback conversation with reporter revealed the following information: the reporter stated that maintenance has released no findings on the cause of the ground air conditioning doors departure. The reporter said early findings suggest the ground air conditioning doors were not properly latched when the air conditioning truck hose was removed. The reporter stated the 2 doors each 3 ft X 3 ft caused damage to the pack doors when they departed.

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Original NASA ASRS Text

Title: A B747-400 ON TKOF CLB AT 6000 FT EXPERIENCED A THUMP BELIEVED TO BE CARGO CONTAINER SHIFT. ON ARR GND AIR CONDITIONING DOORS FOUND MISSING.

Narrative: CLBING W OUT OF ZZZ AND JUST W OF THE SHORELINE AT PROBABLY 6000 FT MSL, WE HEARD A THUMP. WE DISCUSSED IT AND DECIDED IT WAS A CARGO BIN THAT SHIFTED. THE PURSER HEARD THE SAME THING AND FELT THE SAME. THERE WERE NO OTHER INDICATIONS OF ANY PROBS. WE ELECTED TO CONTINUE THE FLT TO ZZZZ. AFTER THE LAYOVER AND ARRIVING AT ZZZZ OPS WE NOTICED THE ACFT STILL ON THE RAMP. WE ASKED OPS WHY. WE WERE TOLD THAT 2 LARGE PANELS COVERING THE AIR CONDITIONING UNITS HAD BEEN PARTIALLY TORN FROM THE ACFT. THIS WAS PROBABLY WHAT WE HEARD. I HAD DONE THE WALKAROUND EARLIER. I HAD PLENTY OF TIME FOR THE WALKAROUND THAT DAY AND HAD SPENT MORE TIME THAN USUAL LOOKING UNDER THE BELLY. I DID NOT NOTICE ANYTHING UNUSUAL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT MAINT HAS RELEASED NO FINDINGS ON THE CAUSE OF THE GND AIR CONDITIONING DOORS DEP. THE RPTR SAID EARLY FINDINGS SUGGEST THE GND AIR CONDITIONING DOORS WERE NOT PROPERLY LATCHED WHEN THE AIR CONDITIONING TRUCK HOSE WAS REMOVED. THE RPTR STATED THE 2 DOORS EACH 3 FT X 3 FT CAUSED DAMAGE TO THE PACK DOORS WHEN THEY DEPARTED.

Data retrieved from NASA's ASRS site as of July 2007 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.