A mechanic reports on installing a B737-800 APU battery in a B757-200 aircraft. Both batteries look ...

Attributes
ACN	816294
Time
Date	200811
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	ground : maintenance
Person 1
Affiliation	company : air carrier
Function	maintenance : technician
Qualification	technician : powerplant technician : airframe
Experience	maintenance technician : 27
ASRS Report	816294
Events
Anomaly	aircraft equipment problem : less severe maintenance problem : improper maintenance non adherence : published procedure non adherence : far
Independent Detector	other other : 1
Resolutory Action	none taken : detected after the fact
Consequence	other
Factors
Maintenance	contributing factor : briefing performance deficiency : non compliance with legal requirements
Supplementary
Problem Areas	Chart Or Publication Maintenance Human Performance Aircraft
Primary Problem	Maintenance Human Performance

Narrative:

I was asked by my lead to replace an APU battery on aircraft. We were very busy and had a lot of work to do. I was working another aircraft at that time. I stopped and went to the storeroom and grabbed the battery I thought was correct. I pulled up the removal and installment maintenance manual paperwork. I pulled the APU circuit breakers and opened the battery access panel. I pulled the battery out on its tracks so I could see the manufacturer's part number. I compared the old battery manufacturer's part number with the new manufacturer's part number on the parts tag. The dash numbers matched; so I removed the old battery and installed the new battery per the maintenance manual. I pushed in all the circuit breakers and closed access panel. I went upstairs to the cockpit and started the APU. It started just fine and checked out fine. I checked the electrical page. The voltage output was good and the battery started to recharge after the start. I filled out the logbook paperwork and parts tag. I have been under a lot of stress lately. I know there is no excuse for my mistake; and I will do my best never to let this happen again. The mistake was found by another employee in ZZZ. His job is to check part numbers to aircraft configns. He had the aircraft stopped and the battery changed.callback conversation with reporter revealed the following information: reporter stated the B757-200 and the B737-800 APU batteries are identical; but the part numbers are not quite the same. The first two and last two numbers on the batteries are the same; but the center numbers are not. Reporter stated since both aircraft APU batteries are identical in looks and functional; his carrier is now working to develop a single part number; or common listing for use on both aircraft types. Reporter stated that for the time being; an additional information notice to mechanics have been added to the APU batteries plastic tag envelope; alerting mechanics to be aware of the current different part numbers.

Original NASA ASRS Text

Title: A MECHANIC REPORTS ON INSTALLING A B737-800 APU BATTERY IN A B757-200 AIRCRAFT. BOTH BATTERIES LOOK IDENTICAL AND ARE FUNCTIONALLY EQUIVALENT TO EACH OTHER; BUT THE PART NUMBERS ARE NOT.

Narrative: I WAS ASKED BY MY LEAD TO REPLACE AN APU BATTERY ON ACFT. WE WERE VERY BUSY AND HAD A LOT OF WORK TO DO. I WAS WORKING ANOTHER ACFT AT THAT TIME. I STOPPED AND WENT TO THE STOREROOM AND GRABBED THE BATTERY I THOUGHT WAS CORRECT. I PULLED UP THE REMOVAL AND INSTALLMENT MAINT MANUAL PAPERWORK. I PULLED THE APU CIRCUIT BREAKERS AND OPENED THE BATTERY ACCESS PANEL. I PULLED THE BATTERY OUT ON ITS TRACKS SO I COULD SEE THE MANUFACTURER'S PART NUMBER. I COMPARED THE OLD BATTERY MANUFACTURER'S PART NUMBER WITH THE NEW MANUFACTURER'S PART NUMBER ON THE PARTS TAG. THE DASH NUMBERS MATCHED; SO I REMOVED THE OLD BATTERY AND INSTALLED THE NEW BATTERY PER THE MAINT MANUAL. I PUSHED IN ALL THE CIRCUIT BREAKERS AND CLOSED ACCESS PANEL. I WENT UPSTAIRS TO THE COCKPIT AND STARTED THE APU. IT STARTED JUST FINE AND CHKED OUT FINE. I CHKED THE ELECTRICAL PAGE. THE VOLTAGE OUTPUT WAS GOOD AND THE BATTERY STARTED TO RECHARGE AFTER THE START. I FILLED OUT THE LOGBOOK PAPERWORK AND PARTS TAG. I HAVE BEEN UNDER A LOT OF STRESS LATELY. I KNOW THERE IS NO EXCUSE FOR MY MISTAKE; AND I WILL DO MY BEST NEVER TO LET THIS HAPPEN AGAIN. THE MISTAKE WAS FOUND BY ANOTHER EMPLOYEE IN ZZZ. HIS JOB IS TO CHK PART NUMBERS TO ACFT CONFIGNS. HE HAD THE ACFT STOPPED AND THE BATTERY CHANGED.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THE B757-200 AND THE B737-800 APU BATTERIES ARE IDENTICAL; BUT THE PART NUMBERS ARE NOT QUITE THE SAME. THE FIRST TWO AND LAST TWO NUMBERS ON THE BATTERIES ARE THE SAME; BUT THE CENTER NUMBERS ARE NOT. REPORTER STATED SINCE BOTH AIRCRAFT APU BATTERIES ARE IDENTICAL IN LOOKS AND FUNCTIONAL; HIS CARRIER IS NOW WORKING TO DEVELOP A SINGLE PART NUMBER; OR COMMON LISTING FOR USE ON BOTH AIRCRAFT TYPES. REPORTER STATED THAT FOR THE TIME BEING; AN ADDITIONAL INFORMATION NOTICE TO MECHANICS HAVE BEEN ADDED TO THE APU BATTERIES PLASTIC TAG ENVELOPE; ALERTING MECHANICS TO BE AWARE OF THE CURRENT DIFFERENT PART NUMBERS.

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.

A mechanic reports on installing a B737-800 APU battery in a B757-200 aircraft. Both batteries look identical and are functionally equivalent to each other; but the part numbers are not.