Narrative:

I was pilot not flying. Captain was pilot flying. We were set up and briefed for [runway] 35C. VMC in between cloud decks. Approaching stonz on BYP5 arrival into dfw; ATC issued us [runway] 35R as landing runway. Captain configured ipad; ILS frequency selection and confirmed minimums. I selected ILS 35R from FMC database. I then 'cleaned up' the legs page and advised captain that [runway] 35R was in box. He acknowledged. Approaching stonz; we were alerted 'discontinuity' by FMS and quickly realized that we had no waypoint after stonz. Autopilot was flying airplane straight ahead; not making expected turn to dirkk. We were soon off course. Captain disengaged autopilot and began left turn back to course. I selected dirkk as next waypoint and adjusted FMS course to match arrival. We returned to course having deviated by approximately 1 mile. I'm aware of the well-known anomaly in the FMS database that causes the entire arrival to be repeated when selecting a different runway at dfw. I immediately 'cleaned up the legs' when the new runway was entered. But; because I selected the same waypoint that I was flying to (the second listing of this waypoint - down the list of waypoints on the arrival) and 'put it on top' of my the current waypoint; the FMS made the update look correctly until the execute button was pressed. Then it simply reverted to the sequence of waypoints that were already in the box (stonz; then a discontinuity; then back to lit and the rest of the fixes). This anomaly is well known - I've seen it before; but I missed it; rushing to get set up. I needed to reverify the legs page after the execute - poor attention to detail. But please; get that anomaly fixed. It's been several years and this problem still exists.

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Original NASA ASRS Text

Title: A B737-800 FMS reverted to the full DFW BYP RNAV arrival beginning at LIT after ATC changed the landing runway to 35R as the aircraft approached STONZ and the crew attempted to change the landing runway.

Narrative: I was pilot not flying. Captain was pilot flying. We were set up and briefed for [Runway] 35C. VMC in between cloud decks. Approaching STONZ on BYP5 Arrival into DFW; ATC issued us [Runway] 35R as landing runway. Captain configured iPad; ILS frequency selection and confirmed minimums. I selected ILS 35R from FMC database. I then 'cleaned up' the legs page and advised Captain that [Runway] 35R was in box. He acknowledged. Approaching STONZ; we were alerted 'Discontinuity' by FMS and quickly realized that we had no waypoint after STONZ. Autopilot was flying airplane straight ahead; not making expected turn to DIRKK. We were soon off course. Captain disengaged autopilot and began left turn back to course. I selected DIRKK as next waypoint and adjusted FMS course to match arrival. We returned to course having deviated by approximately 1 mile. I'm aware of the well-known anomaly in the FMS database that causes the entire arrival to be repeated when selecting a different runway at DFW. I immediately 'cleaned up the legs' when the new runway was entered. BUT; because I selected the same waypoint that I was flying to (the second listing of this waypoint - down the list of waypoints on the arrival) and 'put it on top' of my the current waypoint; the FMS made the update look correctly until the Execute button was pressed. Then it simply reverted to the sequence of waypoints that were already in the box (STONZ; then a discontinuity; then back to LIT and the rest of the fixes). This anomaly is well known - I've seen it before; but I missed it; rushing to get set up. I needed to reverify the legs page after the Execute - poor attention to detail. But please; get that anomaly fixed. It's been several years and this problem still exists.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.