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.