Narrative:

I was approaching the ind airport from the north and received a vector of 180 degrees around the west of the airport for the ILS for runway 5L. I was level at 3000 ft MSL west of the airport when I received the instruction to turn left to 140 degrees and descend to 2500 ft MSL and that I had traffic ahead. This was an effort by the controller to get me near the airport in the hopes that I could complete the visual approach to runway 5L. We had spoken about trying to accomplish this, as another aircraft did the same thing earlier. In my reply to the controller, I acknowledged the heading and altitude, and in addition that I had traffic at my 10 O'clock position and a little below my altitude and that 'I didn't think it was my guy.' the controller responded that it was my traffic to the left at 2300 ft MSL, and follow him for runway 5L. I turned towards the traffic to follow him on final and approximately 1 min later the controller switched me to tower on 120.9. I called tower and told them that I was with them, #2 for runway 5L. The controller exclaimed that I was supposed to be on 121.1 and on a heading of 140 degrees and 2500 ft (which I was at 2500 ft, but not on heading since I was following what I was told was my traffic!). Moments later, while I was turning back to 140 degrees, holding 2500 ft MSL and tuning 121.1, I noticed landing lights coming out of 'the murk' not too far from myself and slightly higher to the right. I immediately turned right to about 260 degrees and called on 121.1. That controller exclaimed I was on the wrong frequency and heading. I switched to that frequency, which was the original controller I had west of the airport, and he calmly, helpfully and quickly explained that I had followed the wrong aircraft (apparently the traffic that I turned to avoid was the DC9 I was supposed to follow). He then asked if I still had the airport in sight and cleared me for the visual for runway 5R. (I was now through the final approach course for runway 5L because after I turned to avoid traffic, I turned back to 140 degrees after it passed. I think that there were several other factors that may have contributed to this occurrence. The first was that while inbound, I was informed that the mode C portion of my transponder system was indicating incorrectly. I assume that the inbound traffic I avoided on the approach to runway 5L had TCASII and I am not sure whether he may have been alerted with the mode C portion of my system turned off as I was requested to do so by ATC. Another factor may have been the WX. It was marginal at the time and I think that a more positive traffic identify may have been made if better conditions were present at the time. The last may have been controller and pilot workload. The frequencys were somewhat busy, and I was also busy as a single pilot working to configure for a quick descent and turn inbound.

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Original NASA ASRS Text

Title: C310 PLT ON A VECTOR TO IND FOR A VISUAL APCH FOLLOWS THE WRONG ACFT AND HAS A CLOSE ENCOUNTER WITH THE DC9 HE WAS TO FOLLOW.

Narrative: I WAS APCHING THE IND ARPT FROM THE N AND RECEIVED A VECTOR OF 180 DEGS AROUND THE W OF THE ARPT FOR THE ILS FOR RWY 5L. I WAS LEVEL AT 3000 FT MSL W OF THE ARPT WHEN I RECEIVED THE INSTRUCTION TO TURN L TO 140 DEGS AND DSND TO 2500 FT MSL AND THAT I HAD TFC AHEAD. THIS WAS AN EFFORT BY THE CTLR TO GET ME NEAR THE ARPT IN THE HOPES THAT I COULD COMPLETE THE VISUAL APCH TO RWY 5L. WE HAD SPOKEN ABOUT TRYING TO ACCOMPLISH THIS, AS ANOTHER ACFT DID THE SAME THING EARLIER. IN MY REPLY TO THE CTLR, I ACKNOWLEDGED THE HDG AND ALT, AND IN ADDITION THAT I HAD TFC AT MY 10 O'CLOCK POS AND A LITTLE BELOW MY ALT AND THAT 'I DIDN'T THINK IT WAS MY GUY.' THE CTLR RESPONDED THAT IT WAS MY TFC TO THE L AT 2300 FT MSL, AND FOLLOW HIM FOR RWY 5L. I TURNED TOWARDS THE TFC TO FOLLOW HIM ON FINAL AND APPROX 1 MIN LATER THE CTLR SWITCHED ME TO TWR ON 120.9. I CALLED TWR AND TOLD THEM THAT I WAS WITH THEM, #2 FOR RWY 5L. THE CTLR EXCLAIMED THAT I WAS SUPPOSED TO BE ON 121.1 AND ON A HDG OF 140 DEGS AND 2500 FT (WHICH I WAS AT 2500 FT, BUT NOT ON HDG SINCE I WAS FOLLOWING WHAT I WAS TOLD WAS MY TFC!). MOMENTS LATER, WHILE I WAS TURNING BACK TO 140 DEGS, HOLDING 2500 FT MSL AND TUNING 121.1, I NOTICED LNDG LIGHTS COMING OUT OF 'THE MURK' NOT TOO FAR FROM MYSELF AND SLIGHTLY HIGHER TO THE R. I IMMEDIATELY TURNED R TO ABOUT 260 DEGS AND CALLED ON 121.1. THAT CTLR EXCLAIMED I WAS ON THE WRONG FREQ AND HDG. I SWITCHED TO THAT FREQ, WHICH WAS THE ORIGINAL CTLR I HAD W OF THE ARPT, AND HE CALMLY, HELPFULLY AND QUICKLY EXPLAINED THAT I HAD FOLLOWED THE WRONG ACFT (APPARENTLY THE TFC THAT I TURNED TO AVOID WAS THE DC9 I WAS SUPPOSED TO FOLLOW). HE THEN ASKED IF I STILL HAD THE ARPT IN SIGHT AND CLRED ME FOR THE VISUAL FOR RWY 5R. (I WAS NOW THROUGH THE FINAL APCH COURSE FOR RWY 5L BECAUSE AFTER I TURNED TO AVOID TFC, I TURNED BACK TO 140 DEGS AFTER IT PASSED. I THINK THAT THERE WERE SEVERAL OTHER FACTORS THAT MAY HAVE CONTRIBUTED TO THIS OCCURRENCE. THE FIRST WAS THAT WHILE INBOUND, I WAS INFORMED THAT THE MODE C PORTION OF MY XPONDER SYS WAS INDICATING INCORRECTLY. I ASSUME THAT THE INBOUND TFC I AVOIDED ON THE APCH TO RWY 5L HAD TCASII AND I AM NOT SURE WHETHER HE MAY HAVE BEEN ALERTED WITH THE MODE C PORTION OF MY SYS TURNED OFF AS I WAS REQUESTED TO DO SO BY ATC. ANOTHER FACTOR MAY HAVE BEEN THE WX. IT WAS MARGINAL AT THE TIME AND I THINK THAT A MORE POSITIVE TFC IDENT MAY HAVE BEEN MADE IF BETTER CONDITIONS WERE PRESENT AT THE TIME. THE LAST MAY HAVE BEEN CTLR AND PLT WORKLOAD. THE FREQS WERE SOMEWHAT BUSY, AND I WAS ALSO BUSY AS A SINGLE PLT WORKING TO CONFIGURE FOR A QUICK DSCNT AND TURN INBOUND.

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.