<< >> NASA ASRS Report 579286, April 2003

An airbus 320, in cruise at FL330, experienced both mcdu's lock up. Resetting circuit breaker functions returned then to normal, under PIC emergency command authority/authorized.

Attributes
ACN	579286
Time
Date	200304
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : las.airport
State Reference	NV
Altitude	msl single value : 33000
Environment
Light	Night
Aircraft 1
Controlling Facilities	artcc : zla.artcc
Operator	common carrier : air carrier
Make Model Name	A320
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	579286
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical non adherence : company policies non adherence : published procedure other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : flt mgmnt display other flight crewa other flight crewb
Resolutory Action	other
Consequence	other other
Supplementary
Problem Areas	Flight Crew Human Performance Maintenance Human Performance Chart Or Publication Aircraft
Primary Problem	Aircraft

Narrative:

While in cruise, both mcdu's failed to respond to pilot inputs. The aircraft remained on course in l-nav mode. Pilots used stand-by navigation procedures to verify course. We contacted dispatch and requested a phone patch with maintenance controller. Maintenance controller had us reset various circuit breakers in an attempt to correct the problem. Both mcdu's remained in the frozen state. Maintenance control recommended a reset of FMGC circuit breaker. Captain's emergency authority/authorized was used, and FMGC circuit breaker was reset. Both mcdu's became operational. Flight continued to destination without incident. ATC was not notified. Aircraft remained on course.

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Original NASA ASRS Text

Title: AN AIRBUS 320, IN CRUISE AT FL330, EXPERIENCED BOTH MCDU'S LOCK UP. RESETTING CIRCUIT BREAKER FUNCTIONS RETURNED THEN TO NORMAL, UNDER PIC EMER COMMAND AUTH.

Narrative: WHILE IN CRUISE, BOTH MCDU'S FAILED TO RESPOND TO PLT INPUTS. THE ACFT REMAINED ON COURSE IN L-NAV MODE. PLTS USED STAND-BY NAV PROCS TO VERIFY COURSE. WE CONTACTED DISPATCH AND REQUESTED A PHONE PATCH WITH MAINT CTLR. MAINT CTLR HAD US RESET VARIOUS CIRCUIT BREAKERS IN AN ATTEMPT TO CORRECT THE PROB. BOTH MCDU'S REMAINED IN THE FROZEN STATE. MAINT CTL RECOMMENDED A RESET OF FMGC CIRCUIT BREAKER. CAPT'S EMER AUTH WAS USED, AND FMGC CIRCUIT BREAKER WAS RESET. BOTH MCDU'S BECAME OPERATIONAL. FLT CONTINUED TO DEST WITHOUT INCIDENT. ATC WAS NOT NOTIFIED. ACFT REMAINED ON COURSE.

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.