Narrative:

While being vectored for approach to runway 17L from the northeast, a speed reduction to 180 KIAS and then a descent from 5000 ft to 3000 ft was assigned. I (PF) was slowing to 180 KIAS and then began my descent as assigned. At approximately 3500 ft we were reassigned runway 17C by approach. PNF said that we had it in sight and I began my left turn to final. We switched to tower and were cleared to land. As I was turning on final to what I thought was runway 17C, another aircraft appeared on TCASII at 200 ft below and 2 O'clock (range approximately 3/4 - 1 1/4 mi). TA issued by TCASII but no RA. We acquired the traffic visually. While turning back to the left to avoid traffic, tower informed us we were lining up for the wrong runway. Tower and us realized this at about the same time. I turned further left to realign the aircraft with runway 17C. We landed without incident but I was extremely angry with my loss of situational awareness. A late change of runway followed by a later than normal handoff to tower had me thinking we were in a different position than we really were. (I thought we were farther from the airport). Yet another example where a few moments of inattn/lack of situational awareness could have caused an incident. My guard was let down and I learned that constant vigilance is the solution.

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Original NASA ASRS Text

Title: MDT CREW HAD A SERIES OF PROBS ON ARR AT DFW.

Narrative: WHILE BEING VECTORED FOR APCH TO RWY 17L FROM THE NE, A SPD REDUCTION TO 180 KIAS AND THEN A DSCNT FROM 5000 FT TO 3000 FT WAS ASSIGNED. I (PF) WAS SLOWING TO 180 KIAS AND THEN BEGAN MY DSCNT AS ASSIGNED. AT APPROX 3500 FT WE WERE REASSIGNED RWY 17C BY APCH. PNF SAID THAT WE HAD IT IN SIGHT AND I BEGAN MY L TURN TO FINAL. WE SWITCHED TO TWR AND WERE CLRED TO LAND. AS I WAS TURNING ON FINAL TO WHAT I THOUGHT WAS RWY 17C, ANOTHER ACFT APPEARED ON TCASII AT 200 FT BELOW AND 2 O'CLOCK (RANGE APPROX 3/4 - 1 1/4 MI). TA ISSUED BY TCASII BUT NO RA. WE ACQUIRED THE TFC VISUALLY. WHILE TURNING BACK TO THE L TO AVOID TFC, TWR INFORMED US WE WERE LINING UP FOR THE WRONG RWY. TWR AND US REALIZED THIS AT ABOUT THE SAME TIME. I TURNED FURTHER L TO REALIGN THE ACFT WITH RWY 17C. WE LANDED WITHOUT INCIDENT BUT I WAS EXTREMELY ANGRY WITH MY LOSS OF SITUATIONAL AWARENESS. A LATE CHANGE OF RWY FOLLOWED BY A LATER THAN NORMAL HDOF TO TWR HAD ME THINKING WE WERE IN A DIFFERENT POS THAN WE REALLY WERE. (I THOUGHT WE WERE FARTHER FROM THE ARPT). YET ANOTHER EXAMPLE WHERE A FEW MOMENTS OF INATTN/LACK OF SITUATIONAL AWARENESS COULD HAVE CAUSED AN INCIDENT. MY GUARD WAS LET DOWN AND I LEARNED THAT CONSTANT VIGILANCE IS THE SOLUTION.

Data retrieved from NASA's ASRS site as of July 2007 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.