Large Transport; Low Wing; 2 Turbojet Eng
Situational Awareness; Human-Machine Interface; Communication Breakdown
ATC Issue All Types; Aircraft Equipment Problem Critical; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented; Flight Crew Requested ATC Assistance / Clarification
Human Factors; Aircraft; Procedure
Flight plan for the LOWGN4 Departure off 18L with a ADM transition. Followed procedures and verified legs on RNAV departure with the FMS.  On taxi out; Tower switched to Runway 17R. Updated FMS; verified RNAV departure with the First Officer. It was the First Officer's takeoff; after passing JGIRL; Departure cleared us direct to BLECO. I did not see BLECO on route; asked Controller for a heading. He gave us a heading; then direct to IRW.  Subsequently; I reviewed the PDC; and the revised segment called for the BLECO4 Departure. Fortunately; both RNAV departures have the  same first four waypoints; so no deviation was incurred. Procedures call for both pilots verifying the PDC with the flight plan. Neither one of us picked up the revised segment. The ACARS print was very light; and I failed to see the revised segment. I will be more attentive when reading the PDC.
A flight crew failed to notice that the lightly printed PDC changed the DFW LOWGN4 RNAV to the BLECO4 and so after being cleared to the BLECO intersection the crew asked for vectors because it was not in the FMS.