RPTR DESCRIBES FLC BECOMING MOMENTARILY DISORIENTED ON LDA APCH.

Narrative

WE WERE RECEIVING VECTORS TO LDA A TO LGA RWY 22; COMING FROM THE N. APCH GAVE US A HDG OF ABOUT 160 DEGS AND TOOK US THROUGH THE LOC FOR SPACING. THE NEXT HDG WAS R TURN TO 260 DEGS. ON THAT HDG WE RECEIVED CLRNC FOR THE APCH. I PUT MY NAV DISPLAY IN ARC. AT THIS TIME I FINISHED UP THE APCH CHK. THE NEXT TIME I CHKED MY NAV DISPLAY WE WERE PAST THE LOC ON THE N SIDE OF THE COURSE. USING THE HDG BUG; I IMMEDIATELY INITIATED A L TURN TO INTERCEPT THE COURSE; AND STATED WE WERE THROUGH THE COURSE. THE CAPT DID NOT SEE THIS; BUT NOTICED I HAD 204 DEGS IN MY COURSE WINDOW INSTEAD OF THE CORRECT COURSE OF 234 DEGS. FINALLY WE BOTH AGREED WE WERE N OF COURSE AND WE MAINTAINED A HDG OF 210 DEGS TO INTERCEPT THE LOC. THE REST OF THE FLT WAS UNEVENTFUL. NO CONFLICT OCCURRED. I ESTIMATE WE WENT 3 MI N OF COURSE. 2 THINGS OCCURRED ON MY PART THAT CONTRIBUTED TO THE SIT. FIRST; I NOTICED THE CAPT DID NOT ARM THE LOC WHEN CLRED APCH. I SAW THAT HE WAS IN ARC AND WOULD NOTICE HIS MISTAKE WHEN THE LOC CAME ALIVE; SO I DID NOT MENTION IT. THE AUTOPLT WAS CONNECTED. SECOND; I MISSED MY LOC ALIVE AND LOC CAPTURE CALLOUTS. I WAS COMPLETING THE APCH CHK WHEN I SHOULD HAVE BEEN MONITORING. THE REASON THE CHK WASN'T DONE EARLIER WAS I WAS SIGHTSEEING TRYING TO PICK OUT THE CITIES IN SW CONNECTICUT. THE VISIBILITY WAS GREAT AND I WAS VERY RELAXED. I DO NOT KNOW WHY THE CAPT DID NOT SEE US GO THROUGH THE COURSE. HE SAID HE NEVER SAW THE COURSE MOVE AND INITIALLY DID NOT AGREE WITH ME WHEN I SAID WE WERE PAST THE LOC. HIS NAV DISPLAY WAS IN ARC AND SHOWED EXACTLY WHAT MINE DID. I THINK IT WOULD HAVE HELPED IF ONE OF US STAYED IN MISSED APCH ON THE NAV DISPLAY.