Reports of incorrect FMC performance software installation on B737 aircraft.

Attributes
ACN	434980
Time
Date	199904
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : stl.airport
State Reference	MO
Altitude	msl single value : 600
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : stl.tower
Operator	common carrier : air carrier
Make Model Name	B737-500
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	ground : preflight
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : private pilot : multi engine pilot : commercial pilot : atp pilot : instrument
Experience	flight time last 90 days : 290 flight time total : 16000 flight time type : 8000
ASRS Report	434980
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : critical non adherence : company policies other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : fmc other flight crewa
Resolutory Action	flight crew : overrode automation flight crew : overcame equipment problem none taken : anomaly accepted
Consequence	other
Factors
Maintenance	contributing factor : engineering procedure performance deficiency : installation
Supplementary
Problem Areas	Maintenance Human Performance Company Aircraft Flight Crew Human Performance
Primary Problem	Company

Narrative:

During preflight, the first officer observed an unexplainable line item on the takeoff reference page of the aircraft FMC/CDU. It now appears the entry may have been the result of an improper database having been loaded in the FMC. The performance data was checked and verified against the aircraft's independent onboard performance computer. No discrepancies were noted. The aircraft was then flown 2 legs, stl-tul, tul-phx with no discrepancies noted. I have subsequently been advised that the CDU had previously been installed in a B737-700 before being installed in aircraft and had not been properly reprogrammed for use in the 500 series aircraft. Although the aircraft computer recognized proper 500 data was installed, it did not (was not able) update itself to eliminate the unexplainable line on the takeoff reference page. Technically I used and flew the aircraft using improper computer information (the database was a combination of 500 and 700 data), but because the FMC was in fact 500 specific and was verified by the independent onboard computer, the aircraft was operated safely.

Original NASA ASRS Text

Title: RPTS OF INCORRECT FMC PERFORMANCE SOFTWARE INSTALLATION ON B737 ACFT.

Narrative: DURING PREFLT, THE FO OBSERVED AN UNEXPLAINABLE LINE ITEM ON THE TKOF REF PAGE OF THE ACFT FMC/CDU. IT NOW APPEARS THE ENTRY MAY HAVE BEEN THE RESULT OF AN IMPROPER DATABASE HAVING BEEN LOADED IN THE FMC. THE PERFORMANCE DATA WAS CHKED AND VERIFIED AGAINST THE ACFT'S INDEPENDENT ONBOARD PERFORMANCE COMPUTER. NO DISCREPANCIES WERE NOTED. THE ACFT WAS THEN FLOWN 2 LEGS, STL-TUL, TUL-PHX WITH NO DISCREPANCIES NOTED. I HAVE SUBSEQUENTLY BEEN ADVISED THAT THE CDU HAD PREVIOUSLY BEEN INSTALLED IN A B737-700 BEFORE BEING INSTALLED IN ACFT AND HAD NOT BEEN PROPERLY REPROGRAMMED FOR USE IN THE 500 SERIES ACFT. ALTHOUGH THE ACFT COMPUTER RECOGNIZED PROPER 500 DATA WAS INSTALLED, IT DID NOT (WAS NOT ABLE) UPDATE ITSELF TO ELIMINATE THE UNEXPLAINABLE LINE ON THE TKOF REF PAGE. TECHNICALLY I USED AND FLEW THE ACFT USING IMPROPER COMPUTER INFO (THE DATABASE WAS A COMBINATION OF 500 AND 700 DATA), BUT BECAUSE THE FMC WAS IN FACT 500 SPECIFIC AND WAS VERIFIED BY THE INDEPENDENT ONBOARD COMPUTER, THE ACFT WAS OPERATED SAFELY.

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.