Reports of incorrect FMC performance software installation on B737 aircraft.

Attributes
ACN	434554
Time
Date	199904
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : tpa.airport
State Reference	FL
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : tpa.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 : multi engine pilot : commercial pilot : atp pilot : instrument
Experience	flight time last 90 days : 150 flight time total : 10300 flight time type : 6600
ASRS Report	434554
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 200 flight time total : 12800 flight time type : 7000
ASRS Report	434836
Events
Anomaly	aircraft equipment problem : critical non adherence : company policies other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : fmc other flight crewa other flight crewb
Resolutory Action	flight crew : overcame equipment problem flight crew : overrode automation none taken : anomaly accepted
Consequence	other
Factors
Maintenance	contributing factor : engineering procedure performance deficiency : repair
Supplementary
Problem Areas	Maintenance Human Performance Aircraft Company Flight Crew Human Performance
Primary Problem	Company

Narrative:

Portions of the FMC performance output were not customary, and differed from the portable onboard performance computer. We verified FMC system effective dates, and followed company procedures to use onboard performance computer data if performance figures varied. All other FMC functions such as navigation data appeared normal. Although the logbook showed a valid FMC service check and airworthiness certificate, improper components or software may have been installed.

Original NASA ASRS Text

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

Narrative: PORTIONS OF THE FMC PERFORMANCE OUTPUT WERE NOT CUSTOMARY, AND DIFFERED FROM THE PORTABLE ONBOARD PERFORMANCE COMPUTER. WE VERIFIED FMC SYS EFFECTIVE DATES, AND FOLLOWED COMPANY PROCS TO USE ONBOARD PERFORMANCE COMPUTER DATA IF PERFORMANCE FIGURES VARIED. ALL OTHER FMC FUNCTIONS SUCH AS NAV DATA APPEARED NORMAL. ALTHOUGH THE LOGBOOK SHOWED A VALID FMC SVC CHK AND AIRWORTHINESS CERTIFICATE, IMPROPER COMPONENTS OR SOFTWARE MAY HAVE BEEN INSTALLED.

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.