A B737-500 was dispatched in non compliance with the incorrect GPWS computer installed.

Attributes
ACN	549262
Time
Date	200205
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Environment
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-500
Operating Under FAR Part	Part 121
Flight Phase	ground : maintenance
Person 1
Affiliation	company : air carrier
Function	maintenance : technician
Qualification	technician : fcc
ASRS Report	549262
Person 2
Affiliation	company : air carrier
Function	oversight : supervisor
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper documentation maintenance problem : improper maintenance non adherence : company policies non adherence : published procedure non adherence : far
Independent Detector	other other : gnd 2
Resolutory Action	none taken : detected after the fact
Consequence	other other
Factors
Maintenance	contributing factor : schedule pressure contributing factor : non availability of parts performance deficiency : fault isolation performance deficiency : logbook entry performance deficiency : installation
Supplementary
Problem Areas	Maintenance Human Performance Aircraft
Primary Problem	Maintenance Human Performance

Narrative:

The affected aircraft arrived with the WX radar/terrain inoperative and deferred. Dispatch refused to continue its current routing due to WX. Through troubleshooting, I narrowed the problem down to the enhanced GPWS computer. The computer was out of stock at my station and I was instructed by my supervisor to rob one from a plane that was going OTS. I robbed the part without positively matching the part numbers, assuming they were the same. Installing the robbed part did not fix the problem. I attempted to retrieve the original part but the aircraft had already departed for the hangar. I was still unaware of the wrong part. The aircraft was rerted with the WX/terrain still deferred. When the deferred item was worked on during overnight maintenance, they discovered the wrong part number was installed. They installed the proper egpws computer and cleared the deferred item. They then informed me of my error.

Original NASA ASRS Text

Title: A B737-500 WAS DISPATCHED IN NON COMPLIANCE WITH THE INCORRECT GPWS COMPUTER INSTALLED.

Narrative: THE AFFECTED ACFT ARRIVED WITH THE WX RADAR/TERRAIN INOP AND DEFERRED. DISPATCH REFUSED TO CONTINUE ITS CURRENT ROUTING DUE TO WX. THROUGH TROUBLESHOOTING, I NARROWED THE PROB DOWN TO THE ENHANCED GPWS COMPUTER. THE COMPUTER WAS OUT OF STOCK AT MY STATION AND I WAS INSTRUCTED BY MY SUPVR TO ROB ONE FROM A PLANE THAT WAS GOING OTS. I ROBBED THE PART WITHOUT POSITIVELY MATCHING THE PART NUMBERS, ASSUMING THEY WERE THE SAME. INSTALLING THE ROBBED PART DID NOT FIX THE PROB. I ATTEMPTED TO RETRIEVE THE ORIGINAL PART BUT THE ACFT HAD ALREADY DEPARTED FOR THE HANGAR. I WAS STILL UNAWARE OF THE WRONG PART. THE ACFT WAS RERTED WITH THE WX/TERRAIN STILL DEFERRED. WHEN THE DEFERRED ITEM WAS WORKED ON DURING OVERNIGHT MAINT, THEY DISCOVERED THE WRONG PART NUMBER WAS INSTALLED. THEY INSTALLED THE PROPER EGPWS COMPUTER AND CLRED THE DEFERRED ITEM. THEY THEN INFORMED ME OF MY ERROR.

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.