Narrative:

Parallel approachs were being conducted at msp on runways 29L/29R. We had been cleared for visual approach on runway 29R. (Field in sight). I engaged the autoplt to conduct an automated turn on to the localizer and GS. (I intended to disengage the autoplt once capture and tracking occurred). (We do this randomly to check autoplt CAT ii certification). All signals were normal and switches on the autoplt correct. The autoplt was in the heading mode and armed for capture. Heading was 260 degrees (40 degrees intercept). Approaching the localizer the autoplt started a slow turn toward the runway (we were about 12 mi from runway). It only banked the aircraft about 5-10 degrees (versus the normal 20-25 degrees). We went through the localizer. I switched the autoplt off and increased bank angle manually to 30 degrees to re-intercept localizer. About this time the TCASII produced an 'RA' and a 'do not descend.' I maintained altitude. Upon visually checking I noticed a turboprop commuter plane on our left side on a straight in approach to runway 29L. He was approximately 300 ft below us and perhaps less than 1000 ft horizontal distance. I maneuvered our aircraft back to the localizer and maintained altitude until on localizer. 'Clear of conflict' sounded while doing this. Upon intercepting the localizer I descended to intercept the GS. The remainder of approach was normal. The frequencys (communication) were different for runways 29L and 29R. The traffic had not been pointed out until after we had established visual contact and the TCASII sounded 'RA.' our excursion did not take us past the midpoint between the 2 parallel runways. However, I should have reacted a little sooner when the autoplt malfunctioned and thus would have avoided the sizeable overshoot that occurred.

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Original NASA ASRS Text

Title: A HDG TRACK DEV PRODUCES A POTENTIAL CONFLICT WITH OTHER ARR TFC.

Narrative: PARALLEL APCHS WERE BEING CONDUCTED AT MSP ON RWYS 29L/29R. WE HAD BEEN CLRED FOR VISUAL APCH ON RWY 29R. (FIELD IN SIGHT). I ENGAGED THE AUTOPLT TO CONDUCT AN AUTOMATED TURN ON TO THE LOC AND GS. (I INTENDED TO DISENGAGE THE AUTOPLT ONCE CAPTURE AND TRACKING OCCURRED). (WE DO THIS RANDOMLY TO CHK AUTOPLT CAT II CERTIFICATION). ALL SIGNALS WERE NORMAL AND SWITCHES ON THE AUTOPLT CORRECT. THE AUTOPLT WAS IN THE HDG MODE AND ARMED FOR CAPTURE. HDG WAS 260 DEGS (40 DEGS INTERCEPT). APCHING THE LOC THE AUTOPLT STARTED A SLOW TURN TOWARD THE RWY (WE WERE ABOUT 12 MI FROM RWY). IT ONLY BANKED THE ACFT ABOUT 5-10 DEGS (VERSUS THE NORMAL 20-25 DEGS). WE WENT THROUGH THE LOC. I SWITCHED THE AUTOPLT OFF AND INCREASED BANK ANGLE MANUALLY TO 30 DEGS TO RE-INTERCEPT LOC. ABOUT THIS TIME THE TCASII PRODUCED AN 'RA' AND A 'DO NOT DSND.' I MAINTAINED ALT. UPON VISUALLY CHKING I NOTICED A TURBOPROP COMMUTER PLANE ON OUR L SIDE ON A STRAIGHT IN APCH TO RWY 29L. HE WAS APPROX 300 FT BELOW US AND PERHAPS LESS THAN 1000 FT HORIZ DISTANCE. I MANEUVERED OUR ACFT BACK TO THE LOC AND MAINTAINED ALT UNTIL ON LOC. 'CLR OF CONFLICT' SOUNDED WHILE DOING THIS. UPON INTERCEPTING THE LOC I DSNDED TO INTERCEPT THE GS. THE REMAINDER OF APCH WAS NORMAL. THE FREQS (COM) WERE DIFFERENT FOR RWYS 29L AND 29R. THE TFC HAD NOT BEEN POINTED OUT UNTIL AFTER WE HAD ESTABLISHED VISUAL CONTACT AND THE TCASII SOUNDED 'RA.' OUR EXCURSION DID NOT TAKE US PAST THE MIDPOINT BTWN THE 2 PARALLEL RWYS. HOWEVER, I SHOULD HAVE REACTED A LITTLE SOONER WHEN THE AUTOPLT MALFUNCTIONED AND THUS WOULD HAVE AVOIDED THE SIZEABLE OVERSHOOT THAT OCCURRED.

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.