Narrative:

The flight departed whiteman airport with an intended course to transition the vny air traffic area southbound along the san diego freeway at 2800' MSL. After permission to change frequency from whiteman tower, I called vny tower to request the described transition. Vny tower granted transition at 2500' MSL and about 1/2 mi east of the san diego freeway. I then complied with these instructions. When I was located at the veteran's hospital (about 2 NM north of vny), I spotted jet traffic at my 2 O'clock position. By the time I was approximately abeam vny, vny tower advised me of my traffic, air carrier medium large transport Y inbound to bur runway 7. I reported 'traffic in sight.' vny instructed me to pass behind the jet. I reported I would pass behind the jet, and that I was reducing my airspeed. I then began a right turn to position myself to pass behind the jet, and about this time the jet passed in front of me at approximately the same altitude (2500' MSL) with (my best estimate) 750-1000' of horizontal sep. As I continuously had the traffic in sight well before it was called to me by vny tower and before it was of any conflict, I did not feel threatened by the jet traffic and no evasive action, in terms of sudden control movements to my aircraft, were required. The significant contributing factor to this incident was that the jet traffic and I were not in communications with the same ATC facility. The location and altitude of the incident was such that I was just on the borderline, or possible inside, the inner core of the bur arsa, yet I was definitely inside the vny air traffic area and thus in ATC communications with vny tower. The jet was also in the vny air traffic area but not in contact with vny tower, but either bur approach control or bur tower. In my opinion, this problem was in part caused by an overlapping area of the vny air traffic area and the inner core of the bur arsa. This creates a zone in which aircraft have 2 different ATC facs in which communications could be established, and apparently one choice is just as valid as the other choice. In this situation, I was geographically much closer to vny tower and thus I felt the better choice was to be in communications with vny tower. The corrective action is to structure boundaries between nearby ATC facs such that these 'communications confusion zones' are eliminated. This could be done by modification, as required, first officer the standard altitude and diameter definitions of an air traffic area to fit local circumstances. In this case, these off-nominal boundaries should be delineated on appropriate sectional charts with corresponding communications frequency. As possible human performance consideration would be to wonder why my initial air traffic area transition request of 2800' MSL southbound along the san freeway was rejected by vny tower in favor of 2500' MSL slightly east of the san freeway. Assuming this jet traffic was on the G/south into bur ILS runway 7, there would have been greater vertical sep if I was at 2800' MSL rather than 2500' MSL. In future flts, I plan to avoid transitions of anata unless it is the last reasonable option, and to further participate in available radar services.

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Original NASA ASRS Text

Title: AIRBORNE CONFLICT BETWEEN SMA SOUTHBOUND ALONG VFR CORRIDOR FROM WHITEMAN AIRPARK, AND ACR MLG ON APCH TO RWY 07 AT BUR JUST TO THE EAST OF VNY.

Narrative: THE FLT DEPARTED WHITEMAN ARPT WITH AN INTENDED COURSE TO TRANSITION THE VNY ATA SBND ALONG THE SAN DIEGO FREEWAY AT 2800' MSL. AFTER PERMISSION TO CHANGE FREQ FROM WHITEMAN TWR, I CALLED VNY TWR TO REQUEST THE DESCRIBED TRANSITION. VNY TWR GRANTED TRANSITION AT 2500' MSL AND ABOUT 1/2 MI E OF THE SAN DIEGO FREEWAY. I THEN COMPLIED WITH THESE INSTRUCTIONS. WHEN I WAS LOCATED AT THE VETERAN'S HOSPITAL (ABOUT 2 NM N OF VNY), I SPOTTED JET TFC AT MY 2 O'CLOCK POS. BY THE TIME I WAS APPROX ABEAM VNY, VNY TWR ADVISED ME OF MY TFC, ACR MLG Y INBND TO BUR RWY 7. I RPTED 'TFC IN SIGHT.' VNY INSTRUCTED ME TO PASS BEHIND THE JET. I RPTED I WOULD PASS BEHIND THE JET, AND THAT I WAS REDUCING MY AIRSPD. I THEN BEGAN A RIGHT TURN TO POS MYSELF TO PASS BEHIND THE JET, AND ABOUT THIS TIME THE JET PASSED IN FRONT OF ME AT APPROX THE SAME ALT (2500' MSL) WITH (MY BEST ESTIMATE) 750-1000' OF HORIZ SEP. AS I CONTINUOUSLY HAD THE TFC IN SIGHT WELL BEFORE IT WAS CALLED TO ME BY VNY TWR AND BEFORE IT WAS OF ANY CONFLICT, I DID NOT FEEL THREATENED BY THE JET TFC AND NO EVASIVE ACTION, IN TERMS OF SUDDEN CONTROL MOVEMENTS TO MY ACFT, WERE REQUIRED. THE SIGNIFICANT CONTRIBUTING FACTOR TO THIS INCIDENT WAS THAT THE JET TFC AND I WERE NOT IN COMS WITH THE SAME ATC FAC. THE LOCATION AND ALT OF THE INCIDENT WAS SUCH THAT I WAS JUST ON THE BORDERLINE, OR POSSIBLE INSIDE, THE INNER CORE OF THE BUR ARSA, YET I WAS DEFINITELY INSIDE THE VNY ATA AND THUS IN ATC COMS WITH VNY TWR. THE JET WAS ALSO IN THE VNY ATA BUT NOT IN CONTACT WITH VNY TWR, BUT EITHER BUR APCH CTL OR BUR TWR. IN MY OPINION, THIS PROB WAS IN PART CAUSED BY AN OVERLAPPING AREA OF THE VNY ATA AND THE INNER CORE OF THE BUR ARSA. THIS CREATES A ZONE IN WHICH ACFT HAVE 2 DIFFERENT ATC FACS IN WHICH COMS COULD BE ESTABLISHED, AND APPARENTLY ONE CHOICE IS JUST AS VALID AS THE OTHER CHOICE. IN THIS SITUATION, I WAS GEOGRAPHICALLY MUCH CLOSER TO VNY TWR AND THUS I FELT THE BETTER CHOICE WAS TO BE IN COMS WITH VNY TWR. THE CORRECTIVE ACTION IS TO STRUCTURE BOUNDARIES BTWN NEARBY ATC FACS SUCH THAT THESE 'COMS CONFUSION ZONES' ARE ELIMINATED. THIS COULD BE DONE BY MODIFICATION, AS REQUIRED, FO THE STANDARD ALT AND DIAMETER DEFINITIONS OF AN ATA TO FIT LCL CIRCUMSTANCES. IN THIS CASE, THESE OFF-NOMINAL BOUNDARIES SHOULD BE DELINEATED ON APPROPRIATE SECTIONAL CHARTS WITH CORRESPONDING COMS FREQ. AS POSSIBLE HUMAN PERFORMANCE CONSIDERATION WOULD BE TO WONDER WHY MY INITIAL ATA TRANSITION REQUEST OF 2800' MSL SBND ALONG THE SAN FREEWAY WAS REJECTED BY VNY TWR IN FAVOR OF 2500' MSL SLIGHTLY E OF THE SAN FREEWAY. ASSUMING THIS JET TFC WAS ON THE G/S INTO BUR ILS RWY 7, THERE WOULD HAVE BEEN GREATER VERT SEP IF I WAS AT 2800' MSL RATHER THAN 2500' MSL. IN FUTURE FLTS, I PLAN TO AVOID TRANSITIONS OF ANATA UNLESS IT IS THE LAST REASONABLE OPTION, AND TO FURTHER PARTICIPATE IN AVAILABLE RADAR SVCS.

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.