A B737-700 PILOT FAILED TO ENGAGE RNAV TO GANDY INTXN AT 420 FT ON THE TPA GANDY ONE RNAV. ATC TRACK DEV WAS FILED.

Narrative

PUSHED ON TIME/TAXIED TO RWY 18R. TOLD TO EXPECT 10 MIN DELAY. INFORMED FLT ATTENDANTS AND PAX. CLRED FOR TKOF. RAN BEFORE TKOF CHKLIST AND RANG FLT ATTENDANTS. COMMENCED TKOF. FIRST TIME TO FLY THIS DEP (GANDY 2). CALLS FOR LNAV AT 420 FT. GANDY IS TO THE W. WAS A LITTLE LATE SELECTING LNAV; ABOUT 700 FT. INITIALLY THE LNAV COMMANDED L TURN. I STARTED TURN TO L TO FOLLOW COMMAND BARS BUT QUICKLY REALIZED THIS WAS INCORRECT; SO I STARTED TURN REVERSAL AND PROGRAMMED FMC FOR DIRECT GANDY. AS WE WERE GOING THROUGH ABOUT 1500 FT AND ALMOST ON HDG FOR GANDY; TWR CAME ON FREQ AND SAID COMPANY FLT NUMBER STOP TURN IMMEDIATELY AND EITHER SAID GO DIRECT GANDY OR GAVE A HDG TO GANDY AND TOLD US TO CALL TWR WHEN WE GOT TO OUR DEST. UPON ARR; I PAGED OUR ATC MGR; BUT RAN OUT OF TIME BEFORE HE CALLED BACK; SO I CALLED TWR. SPOKE WITH THE SUPVR LINE MGR. HE SAID THERE WAS NO CONFLICT AND ALSO SAID THEY HAD HAD NUMEROUS AIRLINERS DO THE SAME THING AND IN PARTICULAR SEVERAL COMPANY ACFT. HE ASKED FOR MY ADDRESS; PHONE AND CERTIFICATE NUMBER AND SAID INTERNAL PAPERWORK HAD BEEN STARTED. WELL; OBVIOUSLY WE THOUGHT WE HAD DONE EVERYTHING CORRECTLY PRIOR TO TKOF. ALL I CAN THINK OF IS BE SURE YOU KNOW WHICH WAY THE INITIAL TURN IS AND LOOK AT THE MAP IF YOU'RE IN A -700.