TAXIING TFC MISSES TURN ON TAXIWAY AND DURING PWR BACK MANEUVER EXPERIENCES A TAXIWAY EXCURSION.

Narrative

WHILE TAXIING OUT OF ROCHESTER; NY (ROC); TO RWY 4; A SHARP R TURN WAS NEEDED TO STAY ON TAXIWAY B; JUST S OF RWY 10. WE KEPT GOING STRAIGHT AND JUST BEGAN TO ENTER A TAXIWAY F. ABOUT THE TIME I HAD REALIZED WE WERE ON THE WRONG TAXIWAY; THE TWR TOLD US TO STOP. THERE WAS A WT RESTRICTION ON THE TAXIWAY. THE CAPT TRIED TO BACK UP TO JOIN TAXIWAY B ONLY 10-15 FT. DURING PUSHBACK THE L AND R MAIN GEAR LEFT THE PAVEMENT UNKNOWN TO US. AFTER GETTING SQUARED AWAY ON ANOTHER TAXIWAY; WE DECIDED TO CHK THE GEAR AND NOTICED WE DID LEAVE THE PAVEMENT. TAXIED BACK TO THE GATE TO GET ACFT CHKED BY MAINT. ACFT FOUND TO BE OK. FLEET MGR WAS INFORMED AND WE DEPARTED ONCE AGAIN FOR CHICAGO. SUPPLEMENTAL INFO FROM ACN 193116: WE ASKED AND RECEIVED PERMISSION FROM GND TO BACK UP A SHORT DISTANCE USING REVERSE AND BE ABLE TO MAKE TURN ONTO B. IN BACKING UP OUR MAIN WHEELS LEFT PAVEMENT WHERE TAXIWAY CURVED. INITIAL CAUSE WAS MISSING 90 DEG R TURN. I HAD GND MAP ON CLIPBOARD. HOWEVER; I LET MYSELF GET DISTRACTED BY THINKING AHEAD TO SOME TAXIING I WOULD HAVE TO DO AROUND CONSTRUCTION WORK AT THE APCH END OF 4. SECOND CAUSE WAS MAKING THE IMPROPER DECISION TO TRY TO BACK UP. I LET THE FOLLOWING ITEMS IMPROPERLY INFLUENCE ME INTO CONSIDERING SOMETHING I SHOULDN'T EVER HAVE TRIED. A) THOUGHT TAXIWAY F WAS STRAIGHT. B) LET MYSELF GET IN A HURRY UP MODE (I.E.; MAKE WHEELS UP TIME; MINIMIZE DELAY TO PAX. C) DISTANCE TO BACK UP WAS VERY SHORT. RECOMMENDATION: ADMIT MISTAKE; GET HELP.