A320 FLT CREW HAS ALTDEV WHILE FLYING AN APCH TO JFK.

Narrative

AFTER FLYING FROM ZZZZ; WE WERE APCHING JFK ON CAMRN FOUR ARR AND VECTORS TO VOR RWY 13L. AFTER PASSING CAMRN POS 11000 FT AND 250 KTS; WE RECEIVED A COUPLE OF VECTORS AND DSCNT INSTRUCTIONS FROM THE RADAR CTLR; SO WE WERE FLYING 200 KTS AT 3000 FT BEFORE THE (IAF) ASALT. THE APCH WAS ALREADY ACTIVATED FOR FLYING A MANAGED APCH. AFTER THE (IAF) THE PF REQUESTED; 'FLAPS 1 ' AND I SET FLAPS 1. HE REQUESTED 'FLAPS 2 AND GEAR DOWN.' I LOWERED THE LNDG GEAR; AND THE CTLR CLRED US FOR THE APCH; SO THE PF PRESSED THE 'APP' PB. AT THAT MOMENT; I THINK I WAS DISTRACTED; BECAUSE I WAS EXPLAINING TO HIM ABOUT THE LDIN (LEAD IN LIGHT SYS) BECAUSE IT WAS HIS FIRST TIME IN NEW YORK AND I WANTED TO GIVE HIM ENOUGH TIPS SO HE WOULD KNOW WHAT TO EXPECT AND WHAT TO LOOK FOR. THE AIRPLANE WAS SUPPOSED TO DSND TO 1500 FT AND CROSS CANARSIE VOR AT 1500 FT AND THEN DSND TO MINIMUM 800 FT. SUDDENLY; I REALIZED THAT INSTEAD OF DSNDING TO 1500 FT; THE ACFT WAS CLBING THROUGH 3300 FT. THE PF ALSO NOTED THAT AND IMMEDIATELY MADE THE PLANE TO DSND. I ESTIMATE THAT WE REACHED 3400 FT. AT THAT TIME; THE CTLR ASKED WHY WERE WE CLBING? I RESPONDED AS PNF; THAT SOMETHING WENT WRONG WITH THE NAV; AND THAT WE WERE ALREADY DSNDING. SO THE CTLR CHANGED US TO TWR. I ESTIMATE THAT WE PASSED CANARSIE VOR AT 2500 FT; AND 1 MI AFTER CANARSIE WE WERE AT 1500 FT LOOKING FOR MINIMUMS OF 800 FT VFR. THE TWR CLRED US FOR LNDG ON RWY 13L. WE CONTINUED FOR LNDG BECAUSE BELOW 1500 FT; THE APCH WAS STABILIZED. I MADE A RPT OF THIS TO THE COMPANY WITH THE INTENTIONS OF FINDING OUT WHAT HAPPENED AND WHY WE WERE CLBING INSTEAD OF DSNDING.