FLC OF A BRITISH JETSTREAM 3100 BA31 FORGOT TO REMOVE THE NOSE GEAR DOWN LOCK PIN PRIOR TO TKOF RESULTING IN RETURN LAND.

Narrative

I ARRIVED AT THE ARPT FOR MY FIRST FLT OFF IOE TO FIND THAT THE ACFT WAS LATE INBOUND AND THAT IT WAS GOING INTO MAINT TO REPLACE A NAV LIGHT. ONCE MAINT WAS FINISHED; I WENT OUT TO THE ACFT; MET THE FO AND COMPLETED MY WALKAROUND AND FOUND EVERYTHING TO BE IN ORDER; INCLUDING NO NOSE PIN INSTALLED. I WAS THEN INFORMED BY RAMP THE ACFT WAS TO BE MOVED TO ANOTHER GATE. THE FO AND I THEN WALKED INSIDE TO THE CREW ROOM WHERE I WATCHED THE ACFT FROM A WINDOW. AFTER APPROX 8 MINS; THE ACFT HAD NOT BEEN MOVED AND NO TOW BAR WAS EVER INSTALLED. I RETURNED TO THE ACFT TO FIND OUT IF THEY WERE GOING TO TOW THE ACFT; ONLY TO FIND OUT THAT WE WERE TO BOARD OUR PAX. I RAN THE CHKS WITH THE FO AS THE PAX WERE BOARDING. THE CHKLIST CALLS FOR THE FO TO RESPOND TO THE CALL 'BAG KEY/NOSE PIN' WITH 'ON BOARD' WHICH HE DID. ON INITIAL CLBOUT; I NOTICED THAT THE NOSE GEAR IN-TRANSIT LIGHT WAS STAYING ON. THE FO CHKED FOR THE NOSE PIN AND FOUND IT WAS NOT IN THE BIN. WE THEN TOLD ATC WE NEEDED TO RETURN FOR LNDG WHICH WE DID AFTER ASKING FOR AND RECEIVING DELAYING VECTORS IN ORDER TO RUN THE APPROPRIATE CHKLISTS. DURING THE TAXI IN I WAS VERY DISTR WITH EVERYTHING RUNNING THROUGH MY MIND -- CHKLISTS; HAS EVERYONE BEEN NOTIFIED; MY CAREER; CHIEF PLTS OFFICE; ATC; PAX; ETC. ATC HAD GIVEN A HOLD SHORT OF A TXWY INSTRUCTION WHICH I ALMOST FAILED TO DO. IN ADDITION; WE WERE TOLD TO 'HOLD SHORT OF TXWY A2.' UNFORTUNATELY; 'GATE XX' AND 'TXWY A2' ARE CLOSE ENOUGH TOGETHER THAT IN MY STATE OF MIND I FAILED TO REALIZE WHICH ONE THE CTLR MEANT AND TAXIED PAST HER INTENDED HOLD POINT OF 'GATE XX.' ONCE WE REACHED OUR GATE WE SHUT DOWN AND FOUND THE NOSE GEAR PIN WAS IN FACT INSTALLED. I BELIEVE THIS HAPPENED BECAUSE I HAD NO REASON TO THINK THE NOSE GEAR PIN HAD BEEN INSTALLED. THE ACFT WAS NEVER MOVED AND NO TOW BAR WAS EVER INSTALLED. IN ADDITION; THE FO SAID HE HAD CHKED IT AFTER MAINT LEFT THE ACFT AND IT WAS ON BOARD. I CHKED IT AS WELL AND IT WAS NOT INSTALLED. BUT; BOTH HE AND I FAILED TO RECHK IT ONCE WE RETURNED TO THE ACFT AND THE RAMP PERSONNEL MISSED THE FLAG HANGING OUT DURING START AND TAXI OUT OFF THE RAMP.