A LEAR 45 FLT CREW INADVERTENTLY TAXI PAST THE RWY 17 HOLD LINE AT MHT.

Narrative

AT MHT; I WAS CLRED TO TAXI TO AND HOLD SHORT OF RWY 17. AS I APCHED THE TXWY TURN AT THE APCH END OF RWY 17; I NOTICED THE LACK OF A HOLD SHORT LINE. AT THE SAME TIME; THE TWR CAME ON FREQ AND ADVISED ME WE HAD CROSSED THE LINE. I MADE A R TURN ON A LARGE APRON AND TAXIED AWAY FROM THE APCH AREA. WE CLRED THE HOLD AREA AND TURNED AROUND. THERE WAS AN ACR ON THE APCH THAT WAS NOT AFFECTED AND WAS ABLE TO CONTINUE HIS APCH. THE TXWY AT THE APCH END OF THE RWY HAS A LARGE APRON. THE HOLD LINE IS A LONG WAY FROM THE APCH END OF THE RWY AND MAKES A TURN ACROSS THE APRON; CREATING A VERY LARGE AREA INSIDE THE HOLD LINE. ONE OF OUR PAX IS A PLT BASED AT MHT; HE RPTED WHAT HAPPENED TO ME IS A COMMON OCCURRENCE; WHICH HAS HAPPENED TO HIM. THIS IS NOT AN EXCUSE; BUT THE AREA IA VERY DIFFERENT FROM WHAT I AM USED TO SEEING AND REQUIRES VIGILANCE ON THE PART OF THE CREW. SUPPLEMENTAL INFO FROM ACN 625203: WHILE TAXI CHKLIST WAS STILL CAUSING MY HEAD TO BE DOWN; PF ASKED WHERE THE HOLD SHORT LINE WAS. SIMULTANEOUSLY THE TWR; WHO WE WERE MONITORING; TOLD US TO 'DO A 180' AND 'HOLD BEHIND THE LINE.'