Both A321 FMGC's transitioned to the basic startup mode with only FMGC; atsu; aids and cids selectio...

Narrative:

While turning and descending during approach at 5;000 ft; pilot not flying asks 'clean it up?' pilot flying responds; 'yes'. Both fmgcs go to basic display of FMGC; atsu; aids; cids. At first I (as pilot flying) thought we had dual FMGC failure. Pushed flight pln button on right FMGC (2L) and only had P position. Athr went off but athr light was still illuminated. I was a bit confused about what I had and didn't have. Conditions were VMC; runway in sight. Turned off autopilot and landed uneventfully. Athr light remained illuminated; even after pushing instinctive disconnect button on thr levers. Event occurred during 'clean up' of flight plan during approach phase into a major airport. [I am] unsure why event occurred. Perhaps improper sequence used during 'clean up' of flight plan; or deleted too much (including runway). Pilot not flying has already stated he knows what he did. On return flight; we were going to review the event sequence; but work load prevented it during approach and landing. If it is possible to get yourself into this situation; this would be a good event for practice in annual simulator cqt.

Original NASA ASRS Text

Title: Both A321 FMGC's transitioned to the basic startup mode with only FMGC; ATSU; AIDS and CIDS selections available when clean up selections were made for the final approach after an RNAV arrival. The failure appears to be the result of a software update error.

Narrative: While turning and descending during approach at 5;000 FT; Pilot Not Flying asks 'Clean it up?' Pilot Flying responds; 'Yes'. Both FMGCs go to basic display of FMGC; ATSU; AIDS; CIDS. At first I (as Pilot Flying) thought we had dual FMGC failure. Pushed FLT PLN button on right FMGC (2L) and only had P POS. ATHR went off but ATHR light was still illuminated. I was a bit confused about what I had and didn't have. Conditions were VMC; runway in sight. Turned off autopilot and landed uneventfully. ATHR light remained illuminated; even after pushing Instinctive Disconnect button on THR levers. Event occurred during 'clean up' of flight plan during approach phase into a major airport. [I am] unsure why event occurred. Perhaps improper sequence used during 'clean up' of flight plan; or deleted too much (including runway). Pilot not flying has already stated he knows what he did. On return flight; we were going to review the event sequence; but work load prevented it during approach and landing. If it is possible to get yourself into this situation; this would be a good event for practice in annual simulator CQT.

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	950578
Time
Date	201105
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Make Model Name	A321
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Component
Aircraft Component	FMS/FMC
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy

Both A321 FMGC's transitioned to the basic startup mode with only FMGC; atsu; aids and cids selections available when clean up selections were made for the final approach after an RNAV arrival. The failure appears to be the result of a software update error.