Narrative:

I contacted TRACON. Informed them that 'I was at 6500 ft with the ATIS, requests an ILS to vny, we are 1 mi west of umber.' after a few seconds, I was assigned a squawk and told 'maintain VFR.' at this time, I noticed a high wing small aircraft Y doing practice maneuvers (ie, stalls, 360's, VMC's) at approximately 5500 ft on the localizer. The controller then informed me 'small aircraft X radar contact umber intersection. Intercept the vny localizer, descend and maintain 5000 maintain VFR.' I replied with a repeat of the instructions, and added the following 'burbank approach, be advised that there is an small aircraft Y doing practice maneuvers, stalls, 360's and such on the localizer.' burbank replied 'roger small aircraft X, make a left 360 turn for spacing.' I began my left turn, and constantly leveled out to look for the above mentioned traffic. I explained to my passenger my reason for the non continuous turn. After about 300 degrees of the turn, I leveled my wings, and immediately noticed the small aircraft Y heading directly towards my 2 O'clock position and less than 500 ft of away. I banked and descended as radically as possible in order to avoid the traffic. In my descent I went from 5500 ft to 4800 ft almost immediately. As I was leveling out, the controller called and asked if I saw a plane moving from my 2-3 O'clock. I told the controller of course. About that time I heard an air carrier flight complain to the same controller about his TCASII going off. Upon landing, I contacted a supervisor at TRACON and asked him to review.

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Original NASA ASRS Text

Title: NMAC.

Narrative: I CONTACTED TRACON. INFORMED THEM THAT 'I WAS AT 6500 FT WITH THE ATIS, REQUESTS AN ILS TO VNY, WE ARE 1 MI W OF UMBER.' AFTER A FEW SECONDS, I WAS ASSIGNED A SQUAWK AND TOLD 'MAINTAIN VFR.' AT THIS TIME, I NOTICED A HIGH WING SMA Y DOING PRACTICE MANEUVERS (IE, STALLS, 360'S, VMC'S) AT APPROX 5500 FT ON THE LOC. THE CTLR THEN INFORMED ME 'SMA X RADAR CONTACT UMBER INTXN. INTERCEPT THE VNY LOC, DSND AND MAINTAIN 5000 MAINTAIN VFR.' I REPLIED WITH A REPEAT OF THE INSTRUCTIONS, AND ADDED THE FOLLOWING 'BURBANK APCH, BE ADVISED THAT THERE IS AN SMA Y DOING PRACTICE MANEUVERS, STALLS, 360'S AND SUCH ON THE LOC.' BURBANK REPLIED 'ROGER SMA X, MAKE A L 360 TURN FOR SPACING.' I BEGAN MY L TURN, AND CONSTANTLY LEVELED OUT TO LOOK FOR THE ABOVE MENTIONED TFC. I EXPLAINED TO MY PAX MY REASON FOR THE NON CONTINUOUS TURN. AFTER ABOUT 300 DEGS OF THE TURN, I LEVELED MY WINGS, AND IMMEDIATELY NOTICED THE SMA Y HDG DIRECTLY TOWARDS MY 2 O'CLOCK POS AND LESS THAN 500 FT OF AWAY. I BANKED AND DSNDED AS RADICALLY AS POSSIBLE IN ORDER TO AVOID THE TFC. IN MY DSCNT I WENT FROM 5500 FT TO 4800 FT ALMOST IMMEDIATELY. AS I WAS LEVELING OUT, THE CTLR CALLED AND ASKED IF I SAW A PLANE MOVING FROM MY 2-3 O'CLOCK. I TOLD THE CTLR OF COURSE. ABOUT THAT TIME I HEARD AN ACR FLT COMPLAIN TO THE SAME CTLR ABOUT HIS TCASII GOING OFF. UPON LNDG, I CONTACTED A SUPVR AT TRACON AND ASKED HIM TO REVIEW.

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.