Narrative:

During departure flight was assigned a heading to intercept J70 east of svm (salem) VOR. The aircraft was being hand flown with managed navigation (IRS coupled to the flight director). Prior to intercept, the captain's (PF) FMGC1 (flight management guidance computer) experienced a momentary 'timeout.' this resulted in a loss of the PF's navigation display until his nd range/mode selector is set to the same setting as the PNF's display. His display is now merely a repeater of the operative system. Immediately prior to intercept, FMGC1 indicated it was ready to return to normal operation. One of us (I think it was me), selected a smaller nd range to obtain a better view of the intercept. Although this is normal operation of the nd's, we again lost the PF's navigation display. FMGC1 had recovered, but the PF's display management computer (dmc) mysteriously remained latched to FMGC2. Again requiring identical nd range/mode selection for proper navigation displays. Except for the nd loss, there was no ECAM indication of the nature of the problem. When we returned to the FMGC 'timeout' confign, we then realized that we had missed the J70 intercept by 3-5 NM. I am not sure if we had failed to rearm the managed navigation mode after FMGC reinstatement or were distracted from ever arming it. In either event, we should have paid closer attention to our flight mode annunciator. The FMA displays which modes the ap, FD, and autothrust are selected or armed. Suggested remedies: always be acutely aware of FMA indications. It's a requirement for 'situational awareness.' once a backup mode is operating normally, don't change it just prior to any intercept/maneuver, etc. We thought we had plenty of time, but the additional dmc anomaly distracted us long enough to miss course intercept.

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Original NASA ASRS Text

Title: ACR FLC SUFFERS HDG TRACK DEV WHEN FAILING TO CAPTURE VOR AIRWAY RADIAL.

Narrative: DURING DEP FLT WAS ASSIGNED A HDG TO INTERCEPT J70 E OF SVM (SALEM) VOR. THE ACFT WAS BEING HAND FLOWN WITH MANAGED NAV (IRS COUPLED TO THE FLT DIRECTOR). PRIOR TO INTERCEPT, THE CAPT'S (PF) FMGC1 (FLT MGMNT GUIDANCE COMPUTER) EXPERIENCED A MOMENTARY 'TIMEOUT.' THIS RESULTED IN A LOSS OF THE PF'S NAV DISPLAY UNTIL HIS ND RANGE/MODE SELECTOR IS SET TO THE SAME SETTING AS THE PNF'S DISPLAY. HIS DISPLAY IS NOW MERELY A REPEATER OF THE OPERATIVE SYS. IMMEDIATELY PRIOR TO INTERCEPT, FMGC1 INDICATED IT WAS READY TO RETURN TO NORMAL OP. ONE OF US (I THINK IT WAS ME), SELECTED A SMALLER ND RANGE TO OBTAIN A BETTER VIEW OF THE INTERCEPT. ALTHOUGH THIS IS NORMAL OP OF THE ND'S, WE AGAIN LOST THE PF'S NAV DISPLAY. FMGC1 HAD RECOVERED, BUT THE PF'S DISPLAY MGMNT COMPUTER (DMC) MYSTERIOUSLY REMAINED LATCHED TO FMGC2. AGAIN REQUIRING IDENTICAL ND RANGE/MODE SELECTION FOR PROPER NAV DISPLAYS. EXCEPT FOR THE ND LOSS, THERE WAS NO ECAM INDICATION OF THE NATURE OF THE PROBLEM. WHEN WE RETURNED TO THE FMGC 'TIMEOUT' CONFIGN, WE THEN REALIZED THAT WE HAD MISSED THE J70 INTERCEPT BY 3-5 NM. I AM NOT SURE IF WE HAD FAILED TO REARM THE MANAGED NAV MODE AFTER FMGC REINSTATEMENT OR WERE DISTRACTED FROM EVER ARMING IT. IN EITHER EVENT, WE SHOULD HAVE PAID CLOSER ATTN TO OUR FLT MODE ANNUNCIATOR. THE FMA DISPLAYS WHICH MODES THE AP, FD, AND AUTOTHRUST ARE SELECTED OR ARMED. SUGGESTED REMEDIES: ALWAYS BE ACUTELY AWARE OF FMA INDICATIONS. IT'S A REQUIREMENT FOR 'SITUATIONAL AWARENESS.' ONCE A BACKUP MODE IS OPERATING NORMALLY, DON'T CHANGE IT JUST PRIOR TO ANY INTERCEPT/MANEUVER, ETC. WE THOUGHT WE HAD PLENTY OF TIME, BUT THE ADDITIONAL DMC ANOMALY DISTRACTED US LONG ENOUGH TO MISS COURSE INTERCEPT.

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.