Confusion
Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Aircraft
I can't say exactly what caused this. Everything was entered correctly into the FMS and the proper navigation mode was selected. The FMS and autopilot had worked correctly prior to and after that fix. The DOMNO fix is the last fix before the arrival splits into one of three directions depending on the runway assigned. My thought is that since there are several brand new procedures into IAH that there could possibly be a bug in the database of the FMS or it was an isolated incident. We were on the new DRLLR one arrival into IAH when I noticed approaching DOMNO intersection that the autopilot was not starting a turn towards DOOOM intersection. We hadn't reached the fix yet but we were at the point where the autopilot starts leading the turn. I quickly checked that the arrival was put in correctly; it was; and that the First Officer had the plane in LNAV; he did. We were now on top of the intersection and I spun the heading bug to point us at DOOOM. The plane crossed over the fix and went into lateral mode so I hit heading mode to get the plane back on course. ATC said it looked like we had just flown over the intersection and I told him that we were navigating towards DOOOM. Nothing else was said and we continued the arrival. I would like to address these descend via arrivals that we are now receiving. Some of these arrivals; including this new DRLLR one in IAH; are increasing the cockpit workload to dangerous levels. I was so busy as pilot monitoring and PIC making sure that all of these step downs and airspeeds were complied with that I was very late at calling in range; getting landing performance; briefing the passengers and setting up for the approach. Our attention is so focused on making sure we comply with the arrival that if any other situation arises such as weather; mechanical issues; passenger issues; approach briefing discussions; we run a very high risk of missing a restriction. I understand that this is the new approach that ATC wants to take with arrival procedures and it probably works great for pilots who fly airplanes that are VNAV equipped but it is creating a hazard to those of us who don't have these capabilities.
Another EMB145 crew experiences the failure of the autopilot to make the turn over the DRLLR fix on the DRLLR 1 RNAV arrival to IAH. Manual intervention minimizes the deviation.