B757-200
Flight Crew Air Transport Pilot (ATP)
Flight Crew Total 18300
Situational Awareness; Confusion; Human-Machine Interface
Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance; Flight Crew Returned To Clearance; Flight Crew Became Reoriented
Human Factors; Aircraft
I read and checked along with First Officer the CLARE TWO RNAV departure out of DFW; way point by way point along with speed and altitude restrictions and all checked good. First Officer flying; 400 FT LNAV; 500 FT autopilot on and I was on the PROG page 2 to check for errors on departure. Everything went perfect in the critical phase right after takeoff up to above approximately 20;000 FT where I went to regular PROG page. Approximately 3 minutes after crossing CLARE ATC asked where we were going since we were about a mile off course. I answered that we were going to SWB because that's what was in the both FMC's. ATC then said we were supposed to fly POTEN; then TEKBE before going to SWB. I was absolutely flabbergasted since we did a VERY thorough check before we left and First Officer clearly remembered that I read POTEN and TEKBE to him when I went through the legs in the FMC. Neither the First Officer nor I have any idea why all of a sudden both FMC's had us going to CLARE and then direct SWB. ATC said 'no problem' and recleared us to SWB.
We agreed to all fixes matching with our flight plan along with distance total coming with a 1 NM difference which is very good with compliance.
A B757 crew verified the FMC flight plan waypoints on the DFW CLARE 2 RNAV during preflight but after takeoff POTEN and TEKBE waypoints dropped out causing a track deviation detected by ATC.