What was found
DURING FLIGHT, THE F/A REPORTED LOAD VIBRATION THAT THE CAPTAIN WAS ABLE TO CONFIRM. THE CREW MADE AN AIR-TURN-BACK. THE AC WAS INSPECTED BY MX WHO FOUND THE LT PACK WAS VENTING AIR. MX REPLACED THE LT PACK AND OPERATIONAL CHECKED THE COLD AIR UNIT ON A DIFFERENT AC AND DETERMINED THE BEARING HAD SEIZED MOST LIKELY BECAUSE OF THE VENTED AIR. AC WAS RETURNED TO SERVICE WITH NO FURTHER DEFECTS. NOTE: THE COLD AIR UNIT HAD JUST BEEN REPLACED ON 9/28/04 AND DID MAKE ONE LEG. (K)