A B737-900 was dispatched with the incorrect main ship's battery installed.

Attributes
ACN	657650
Time
Date	200505
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Environment
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-900
Operating Under FAR Part	Part 121
Flight Phase	ground : maintenance
Person 1
Affiliation	company : air carrier
Function	maintenance : technician
Qualification	controller : developmental
Experience	maintenance avionics : 12 maintenance repairman : 12
ASRS Report	657650
Person 2
Affiliation	company : air carrier
Function	maintenance : technician
Qualification	technician : repairman
Experience	maintenance avionics : 15 maintenance repairman : 15
ASRS Report	657649
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper documentation maintenance problem : improper maintenance non adherence : company policies non adherence : far non adherence : published procedure
Independent Detector	other other : 3
Resolutory Action	none taken : detected after the fact
Consequence	other
Factors
Maintenance	contributing factor : manuals performance deficiency : scheduled maintenance performance deficiency : inspection performance deficiency : logbook entry performance deficiency : installation performance deficiency : non compliance with legal requirements
Supplementary
Problem Areas	Maintenance Human Performance Chart Or Publication Aircraft Environmental Factor
Primary Problem	Maintenance Human Performance

Narrative:

Main ship battery was determined to be an incorrect part number. The mistake I made was both batteries look the same; but I was not able to detect the differences because my co-worker helped to fill out the parts tag. So I assumed that it was the correct part installed. Part box was labeled correctly; but part inside box was for different type aircraft.

Original NASA ASRS Text

Title: A B737-900 WAS DISPATCHED WITH THE INCORRECT MAIN SHIP'S BATTERY INSTALLED.

Narrative: MAIN SHIP BATTERY WAS DETERMINED TO BE AN INCORRECT PART NUMBER. THE MISTAKE I MADE WAS BOTH BATTERIES LOOK THE SAME; BUT I WAS NOT ABLE TO DETECT THE DIFFERENCES BECAUSE MY CO-WORKER HELPED TO FILL OUT THE PARTS TAG. SO I ASSUMED THAT IT WAS THE CORRECT PART INSTALLED. PART BOX WAS LABELED CORRECTLY; BUT PART INSIDE BOX WAS FOR DIFFERENT TYPE ACFT.

Data retrieved from NASA's ASRS site as of January 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.