Narrative:

During brake change night shift; inadvertently a brake assembly B737-700 was installed on a B737-800. The brake was a B737-700 'only' brake assembly. I was lead mechanic in charge of crew. Large workload; new mechanics and rushed ETA situation contributed to error. The new brake installed came in container marked B737-800. ZZZ is not normally allocated -700 brakes. I verified manufacturer's part number via new mechanic who read manufacturer's part number to me. Either he read the wrong manufacturer's part number from old brake assembly or I heard the mechanic in error. The wrong brake assembly was installed. The non-routine was signed by myself and inspection. The manufacturer's part number for a -700 brake assembly and -800 are off by one number. Note: I had ordered a -800 brake assembly from stores; a -700 brake was delivered. Still; I; being the lead; signed off the brake even though the new mechanics had done the work. The event should not have happened. Callback conversation with reporter revealed the following information: reporter stated the brake was being changed for wear. The B737-700 and -800 brake assemblies look almost identical and have the same mounting arrangement to the main landing gear. The -800 brakes are heavier. Even though the new brake was a -700 and came in a shipping container marked -800; the miscommunication he had with the new mechanic involving the part number verification didn't help. Reporter stated since he had signed for the brake installation; he should have visually verified the part numbers on the brake assemblies with the ipc and parts tag. Reporter stated his carrier intends to improve the labeling of the two different brakes so they will be clearly marked for -700 and -800 aircraft.

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Original NASA ASRS Text

Title: A LEAD MECHANIC REPORTS A B737-700 BRAKE ASSEMBLY WAS INADVERTENTLY INSTALLED ON A B737-800 AT THE LEFT OUTBOARD (#1) POSITION OF THE LEFT MAIN LANDING GEAR.

Narrative: DURING BRAKE CHANGE NIGHT SHIFT; INADVERTENTLY A BRAKE ASSEMBLY B737-700 WAS INSTALLED ON A B737-800. THE BRAKE WAS A B737-700 'ONLY' BRAKE ASSEMBLY. I WAS LEAD MECH IN CHARGE OF CREW. LARGE WORKLOAD; NEW MECHS AND RUSHED ETA SITUATION CONTRIBUTED TO ERROR. THE NEW BRAKE INSTALLED CAME IN CONTAINER MARKED B737-800. ZZZ IS NOT NORMALLY ALLOCATED -700 BRAKES. I VERIFIED MANUFACTURER'S PART NUMBER VIA NEW MECH WHO READ MANUFACTURER'S PART NUMBER TO ME. EITHER HE READ THE WRONG MANUFACTURER'S PART NUMBER FROM OLD BRAKE ASSEMBLY OR I HEARD THE MECH IN ERROR. THE WRONG BRAKE ASSEMBLY WAS INSTALLED. THE NON-ROUTINE WAS SIGNED BY MYSELF AND INSPECTION. THE MANUFACTURER'S PART NUMBER FOR A -700 BRAKE ASSEMBLY AND -800 ARE OFF BY ONE NUMBER. NOTE: I HAD ORDERED A -800 BRAKE ASSEMBLY FROM STORES; A -700 BRAKE WAS DELIVERED. STILL; I; BEING THE LEAD; SIGNED OFF THE BRAKE EVEN THOUGH THE NEW MECHS HAD DONE THE WORK. THE EVENT SHOULD NOT HAVE HAPPENED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THE BRAKE WAS BEING CHANGED FOR WEAR. THE B737-700 AND -800 BRAKE ASSEMBLIES LOOK ALMOST IDENTICAL AND HAVE THE SAME MOUNTING ARRANGEMENT TO THE MAIN LANDING GEAR. THE -800 BRAKES ARE HEAVIER. EVEN THOUGH THE NEW BRAKE WAS A -700 AND CAME IN A SHIPPING CONTAINER MARKED -800; THE MISCOMMUNICATION HE HAD WITH THE NEW MECHANIC INVOLVING THE PART NUMBER VERIFICATION DIDN'T HELP. REPORTER STATED SINCE HE HAD SIGNED FOR THE BRAKE INSTALLATION; HE SHOULD HAVE VISUALLY VERIFIED THE PART NUMBERS ON THE BRAKE ASSEMBLIES WITH THE IPC AND PARTS TAG. REPORTER STATED HIS CARRIER INTENDS TO IMPROVE THE LABELING OF THE TWO DIFFERENT BRAKES SO THEY WILL BE CLEARLY MARKED FOR -700 AND -800 AIRCRAFT.

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.