A319 flight crew reports FCU1 failure during descent causing altitude set window to change by one th...

Attributes
ACN	753908
Time
Date	200709
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl bound lower : 36000 msl bound upper : 39000
Aircraft 1
Controlling Facilities	artcc : zzz.artcc
Operator	common carrier : air carrier
Make Model Name	A319
Operating Under FAR Part	Part 121
Flight Phase	descent : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	753908
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	aircraft equipment other aircraft equipment : ecam other flight crewa
Resolutory Action	flight crew : overcame equipment problem
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

In descent from FL390 passing about FL360; got ECAM automatic flight FCU 1 fail. First officer was PF and autoplt #2 was engaged in navigation and managed descent. Cleared ECAM and noticed that altitude set in FCU window had changed by itself from 32000 ft to 33000 ft. We changed it back to 32000 ft and continued descent. Wrote it up in ZZZ and told maintenance what had happened. I have been on the airbus over 5 yrs and have never seen FCU altitude window setting change by itself before. I am very concerned about the potential this represents. Fortunately; we caught it right away. This could have been very bad.

Original NASA ASRS Text

Title: A319 FLT CREW REPORTS FCU1 FAILURE DURING DESCENT CAUSING ALTITUDE SET WINDOW TO CHANGE BY ONE THOUSAND FEET.

Narrative: IN DSCNT FROM FL390 PASSING ABOUT FL360; GOT ECAM AUTO FLT FCU 1 FAIL. FO WAS PF AND AUTOPLT #2 WAS ENGAGED IN NAV AND MANAGED DSCNT. CLRED ECAM AND NOTICED THAT ALT SET IN FCU WINDOW HAD CHANGED BY ITSELF FROM 32000 FT TO 33000 FT. WE CHANGED IT BACK TO 32000 FT AND CONTINUED DSCNT. WROTE IT UP IN ZZZ AND TOLD MAINT WHAT HAD HAPPENED. I HAVE BEEN ON THE AIRBUS OVER 5 YRS AND HAVE NEVER SEEN FCU ALT WINDOW SETTING CHANGE BY ITSELF BEFORE. I AM VERY CONCERNED ABOUT THE POTENTIAL THIS REPRESENTS. FORTUNATELY; WE CAUGHT IT RIGHT AWAY. THIS COULD HAVE BEEN VERY BAD.

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.

A319 flight crew reports FCU1 failure during descent causing altitude set window to change by one thousand feet.