Altitude excursion by an A320 flight crew when their FMC system fails on frequency with ZID, in.

Attributes
ACN	509830
Time
Date	200105
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : zid.artcc
State Reference	IN
Altitude	msl single value : 33000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	A320
Flight Phase	cruise : level
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : multi engine pilot : instrument pilot : cfi pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 100 flight time total : 13000 flight time type : 100
ASRS Report	509830
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude non adherence : clearance
Resolutory Action	controller : issued advisory flight crew : became reoriented flight crew : overcame equipment problem flight crew : returned to assigned altitude flight crew : overrode automation
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

During cruise flight at FL330 on ATC vector, aircraft experienced a dual FMGC reset. During this period, tawe lost autothrottles, autoplt, all navigation capability, map displays and had several ECAM messages and aural warnings. I immediately began flying aircraft and first officer attempted to resolve FMGC problem. At the same time, flight attendant came to the flight deck and ATC gave us an altitude climb to FL370. We advised we would stay at FL330. During this period, the aircraft drifted up to FL333, setting off altitude alerter. Returned aircraft to FL330 and ATC asked for altitude. We advised at FL330 and told them we had navigation problems. They gave us another vector and we were able to get computers back on line and continued flight to destination.

Original NASA ASRS Text

Title: ALT EXCURSION BY AN A320 FLT CREW WHEN THEIR FMC SYS FAILS ON FREQ WITH ZID, IN.

Narrative: DURING CRUISE FLT AT FL330 ON ATC VECTOR, ACFT EXPERIENCED A DUAL FMGC RESET. DURING THIS PERIOD, TAWE LOST AUTOTHROTTLES, AUTOPLT, ALL NAV CAPABILITY, MAP DISPLAYS AND HAD SEVERAL ECAM MESSAGES AND AURAL WARNINGS. I IMMEDIATELY BEGAN FLYING ACFT AND FO ATTEMPTED TO RESOLVE FMGC PROB. AT THE SAME TIME, FLT ATTENDANT CAME TO THE FLT DECK AND ATC GAVE US AN ALT CLB TO FL370. WE ADVISED WE WOULD STAY AT FL330. DURING THIS PERIOD, THE ACFT DRIFTED UP TO FL333, SETTING OFF ALT ALERTER. RETURNED ACFT TO FL330 AND ATC ASKED FOR ALT. WE ADVISED AT FL330 AND TOLD THEM WE HAD NAV PROBS. THEY GAVE US ANOTHER VECTOR AND WE WERE ABLE TO GET COMPUTERS BACK ON LINE AND CONTINUED FLT TO DEST.

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.