Date: 201503
Local time of day: 0601-1200
Location: ATL.Airport, GA
Flight conditions: Mixed
Weather elements / visibility: 1.5
Light: Daylight
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class B ATL
Reporter organization: Air Carrier
Reporter function: First Officer
Human factors: Workload; Time Pressure; Human-Machine Interface; Distraction; Confusion
Second reporter function: Captain
Anomaly: Aircraft Equipment Problem Critical; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert; Flight Crew Returned To Clearance
Contributing factors: Human Factors; Procedure; Chart Or Publication
Primary problem: Procedure

Narrative: During the arrival on the KOLTT RNAV into Atlanta; ATC changed the transition from 08L to 09R. While sequencing us for the ILS PRM 09R; just prior to ANDIY; ATC had us slow from 250 knots to 210 knots and also cleared us to descend from 8000 feet to 6000 feet.  Just moments prior to reaching ANDIY; we were cleared for the ILS PRM 09R approach.  Once cleared; we closed the discontinuity but the aircraft didn't start the turn toward DFINS.  The FMS was in LNAV and VNAV. Upon reaching ANDIY and noticing the aircraft not turning toward DFINS; we initiated a turn to DFINS. Simultaneously; ATC provided us with a vector. We landed without any further complications.An earlier clearance for the ILS PRM 09R would have mitigated this incident.  Even with the FMS programmed correctly with the discontinuity after DFINS; the 09R transition; the LEGS page and Navigation Display (ND) displayed the correct routing; NAVVY; ANDIY; and then DFINS.  Upon receiving clearance and closing the discontinuity; the aircraft didn't turn to DFINS; which led us to initiate a turn and ATC providing us a vector.


Second narrative: We were busy resetting the instruments. We were not cleared the transition from the arrival to 9R until close to the transition fix at which point I noticed we did not have the discontinuity closed. I should have been more prepared for the common runway change environment in ATL. Also; a more disciplined runway change procedure in the cockpit would have aided the situation.


Synopsis: A B737-700 flight crew inbound to ATL on the KOLTT RNAV STAR; Precision Runway Monitor (PRM) runway 08L received a last second runway change to 09R which requires an entirely different routing from KOLTT and branches off the common portion of the STAR 3.3NM sooner than required for 08L. Unable to complete the altered programming and immediately cleared for the PRM Runway 09R approach the FMS was unable to direct the ~80 degree course change required at ANDIY.  The flight crew struggled to manually make the adjustment and ATC simultaneously provided a vector in a commingled attempt to save the arrival and maintain separation with other aircraft.  Both pilots cited the difficulty associated with complying with very late runway change assignments on complex RNAV STARs.