A319 capitan describes a #2 FMGC failure that does not cause the #2 autopilot to disengage and resul...

Narrative:

During the descent we received a 'cabin attendant pr elev fault' ECAM. I called the ECAM and told the first officer that he had the airplane and radios and I would run the ECAM. After completing the ECAM we then lost the first officer's nd display (map). While this was going on we were descending using the 'managed altitude setting SOP'. There were a few more warnings and inoperative systems and the first officer's mcdu locked up. We started to suspect a failed fmcg but there was nothing that made this clear (after landing we realized we should have looked for the 1fd1 on the pfd). The airplane was on autopilot #2 and never kicked off. The altitude alert was set for 7;000 ft which was the lowest altitude on the arrival. Approach asked for our altitude and when I looked up from working the failing systems I saw we were at 7;000 ft. I then looked at my map and saw that the altitude constraint showed we should be at 8;000. I told them we were at 7;000 and I told them we were 1;000 ft too low. Approach told us to maintain 7;000. I double checked and saw that the #2 autopilot was still on and that all the correct annunciations were displayed. It was about this time the airplane needed to make a lateral course change. I noticed that the airplane was not making the required turn. I told the first officer to turn off the autopilot and hand fly.here are the highlights. While working the ECAM and trying to figure out what was failing we did not monitor the altitude constraints and trusted the auto-flight systems. Because of the failure of the fmcg #2 the auto-flight system did not adhere to the displayed constraints. I did not know that the autopilot would stay connected and the F/D would display guidance with unreliable information. I am not sure what the autopilot was doing but it was still our fault for not monitoring the flight path.

Original NASA ASRS Text

Title: A319 Capitan describes a #2 FMGC failure that does not cause the #2 Autopilot to disengage and results in descent below programed altitude on the RNAV arrival.

Narrative: During the descent we received a 'CAB PR ELEV FAULT' ECAM. I called the ECAM and told the First Officer that he had the airplane and radios and I would run the ECAM. After completing the ECAM we then lost the First Officer's ND display (map). While this was going on we were descending using the 'Managed Altitude Setting SOP'. There were a few more warnings and inoperative systems and the First Officer's MCDU locked up. We started to suspect a failed FMCG but there was nothing that made this clear (after landing we realized we should have looked for the 1FD1 on the PFD). The airplane was on autopilot #2 and never kicked off. The altitude alert was set for 7;000 FT which was the lowest altitude on the arrival. Approach asked for our altitude and when I looked up from working the failing systems I saw we were at 7;000 FT. I then looked at my map and saw that the altitude constraint showed we should be at 8;000. I told them we were at 7;000 and I told them we were 1;000 FT too low. Approach told us to maintain 7;000. I double checked and saw that the #2 autopilot was still on and that all the correct annunciations were displayed. It was about this time the airplane needed to make a lateral course change. I noticed that the airplane was not making the required turn. I told the First Officer to turn off the autopilot and hand fly.Here are the highlights. While working the ECAM and trying to figure out what was failing we did not monitor the altitude constraints and trusted the auto-flight systems. Because of the failure of the FMCG #2 the auto-flight system did not adhere to the displayed constraints. I did not know that the autopilot would stay connected and the F/D would display guidance with unreliable information. I am not sure what the autopilot was doing but it was still our fault for not monitoring the flight path.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	910412
Time
Date	201009
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.TRACON
State Reference	US
Aircraft 1
Make Model Name	A319
Operating Under FAR Part	Part 121
Flight Phase	Descent
Component
Aircraft Component	FMS/FMC
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 84 Flight Crew Total 13500 Flight Crew Type 600
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Altitude Overshoot

A319 capitan describes a #2 FMGC failure that does not cause the #2 autopilot to disengage and results in descent below programed altitude on the RNAV arrival.