Narrative:

We were about 9 mi northeast of den and being vectored for a visual approach to runway 17L. After a series of heading, altitude, and speed changes, we were on a left base for runway 17L with the airport in sight. ATC pointed out traffic at our 12 O'clock position and asked if we had the aircraft in sight. The captain said he did and I replied in the affirmative. ATC then cleared us for a visual approach to follow that aircraft to runway 17L. We were about 3-4 mi from the final approach course. I looked down to identify the localizer for runway 17L. After I had completed the identify, I looked up at the ehsi and noticed that we were less than a mi from the final approach course and the captain had not begun a turn to final. I immediately said, 'you're going to overshoot final' and the captain began a left turn to intercept. Due to our speed and the late turn, we overshot final by more than a mi and ATC said something like 'air carrier, are you going to make that turn?' the captain rolled into a hard right turn. Surprised at this unexpected turn, I asked what he was doing. He responded, 'tell ATC I'm going to make a right 270 degree turn to reintercept the final.' even though I didn't think this was a wise maneuver with parallel traffic for runway 17R nearby, I decided it was better to inform ATC of our action rather than debate it with the captain. When I informed ATC that we were now in a right 270 degree turn they responded, 'no, no, no, turn left immediately!' ATC was probably upset due to the parallel traffic for runway 17R being in close proximity. We complied with the ATC instruction, reintercepted the runway 17L final and landed without further incident. The captain later explained that he suddenly thought that a right 270 degree turn would have been more efficient to reintercept the final, but he forgot to consider the parallel traffic. Supplemental information from acn 311970: my understanding was that the traffic was for runway 17L, and we were to follow it to the airport. The spacing seemed somewhat 'tight,' so I started adjusting for this contingency, ie, slowing and squaring off the pattern. The more important task of lining up with the correct runway became secondary. I will turn off my flight director on a visual approach, but did not do so on this morning. Extended runway ctrlines have been 'sacred' to me on visual approachs and I favor my side on any parallel visual approach.

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Original NASA ASRS Text

Title: LTSS ON THE FINAL APCH COURSE.

Narrative: WE WERE ABOUT 9 MI NE OF DEN AND BEING VECTORED FOR A VISUAL APCH TO RWY 17L. AFTER A SERIES OF HDG, ALT, AND SPD CHANGES, WE WERE ON A L BASE FOR RWY 17L WITH THE ARPT IN SIGHT. ATC POINTED OUT TFC AT OUR 12 O'CLOCK POS AND ASKED IF WE HAD THE ACFT IN SIGHT. THE CAPT SAID HE DID AND I REPLIED IN THE AFFIRMATIVE. ATC THEN CLRED US FOR A VISUAL APCH TO FOLLOW THAT ACFT TO RWY 17L. WE WERE ABOUT 3-4 MI FROM THE FINAL APCH COURSE. I LOOKED DOWN TO IDENT THE LOC FOR RWY 17L. AFTER I HAD COMPLETED THE IDENT, I LOOKED UP AT THE EHSI AND NOTICED THAT WE WERE LESS THAN A MI FROM THE FINAL APCH COURSE AND THE CAPT HAD NOT BEGUN A TURN TO FINAL. I IMMEDIATELY SAID, 'YOU'RE GOING TO OVERSHOOT FINAL' AND THE CAPT BEGAN A L TURN TO INTERCEPT. DUE TO OUR SPD AND THE LATE TURN, WE OVERSHOT FINAL BY MORE THAN A MI AND ATC SAID SOMETHING LIKE 'ACR, ARE YOU GOING TO MAKE THAT TURN?' THE CAPT ROLLED INTO A HARD R TURN. SURPRISED AT THIS UNEXPECTED TURN, I ASKED WHAT HE WAS DOING. HE RESPONDED, 'TELL ATC I'M GOING TO MAKE A R 270 DEG TURN TO REINTERCEPT THE FINAL.' EVEN THOUGH I DIDN'T THINK THIS WAS A WISE MANEUVER WITH PARALLEL TFC FOR RWY 17R NEARBY, I DECIDED IT WAS BETTER TO INFORM ATC OF OUR ACTION RATHER THAN DEBATE IT WITH THE CAPT. WHEN I INFORMED ATC THAT WE WERE NOW IN A R 270 DEG TURN THEY RESPONDED, 'NO, NO, NO, TURN L IMMEDIATELY!' ATC WAS PROBABLY UPSET DUE TO THE PARALLEL TFC FOR RWY 17R BEING IN CLOSE PROX. WE COMPLIED WITH THE ATC INSTRUCTION, REINTERCEPTED THE RWY 17L FINAL AND LANDED WITHOUT FURTHER INCIDENT. THE CAPT LATER EXPLAINED THAT HE SUDDENLY THOUGHT THAT A R 270 DEG TURN WOULD HAVE BEEN MORE EFFICIENT TO REINTERCEPT THE FINAL, BUT HE FORGOT TO CONSIDER THE PARALLEL TFC. SUPPLEMENTAL INFO FROM ACN 311970: MY UNDERSTANDING WAS THAT THE TFC WAS FOR RWY 17L, AND WE WERE TO FOLLOW IT TO THE ARPT. THE SPACING SEEMED SOMEWHAT 'TIGHT,' SO I STARTED ADJUSTING FOR THIS CONTINGENCY, IE, SLOWING AND SQUARING OFF THE PATTERN. THE MORE IMPORTANT TASK OF LINING UP WITH THE CORRECT RWY BECAME SECONDARY. I WILL TURN OFF MY FLT DIRECTOR ON A VISUAL APCH, BUT DID NOT DO SO ON THIS MORNING. EXTENDED RWY CTRLINES HAVE BEEN 'SACRED' TO ME ON VISUAL APCHS AND I FAVOR MY SIDE ON ANY PARALLEL VISUAL APCH.

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.