Narrative:

I had just had my transponder/mode C repaired at dpa, was returning to cgx to pick up passenger. Departed 150 degree from dpa, then turned 090 to mdw to remain under 3000' base of TCA, flying at 1800 MSL as buffer. Communication established with midway radar 119.45 at 11 NM west. They vectored me 040 to stay north of mdw, instead of direct overflt, and said the 'would turn me eastbound later'. I received a traffic advisory of an small aircraft at 1600 2 mi also nebnd, not in sight, then told me to follow the eisenhower, 3 NM ahead. In the hazy conditions I was looking for traffic and visually navigating and became uncertain of expressway location (actually only 1 NM ahead) versus another road, all the while concerned of nearby lower traffic. I questioned them 'if the eisenhower was the road beneath me now' to which I received 'affirmative'. I immediately noticed my altitude had deviated to almost 2000 MSL (there was continuous light turbulence in thermal instability) and as I was descending back to 1800 I was instructed to 'maintain at or below 1700'. Meanwhile I found my small aircraft traffic at 1600 and about 1 mile. The rest of the flight was uneventful. I'm not sure if midway radar thought I violated the TCA, but they did cause several problems for me. 1) vectored me out of a 3000' TCA floor area into a 1900' area, without warning of TCA, negating my buffer zone. 2) misled me as to distance of expressway, confusing the issue. 3) vectored me into a potential traffic conflict with another aircraft going the same direction. If they are going to vector us toward a TCA boundary change we ought to be notified. This prospect bothers me almost as much as the ATC-initiated traffic conflict.

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Original NASA ASRS Text

Title: ATC VECTORS PROVIDED TO TRANSIENT VFR TRAFFIC MAY HAVE RESULTED IN REPORTER INADVERTENTLY ENTERING TCA WITHOUT ATC CLRNC.

Narrative: I HAD JUST HAD MY XPONDER/MODE C REPAIRED AT DPA, WAS RETURNING TO CGX TO PICK UP PAX. DEPARTED 150 DEG FROM DPA, THEN TURNED 090 TO MDW TO REMAIN UNDER 3000' BASE OF TCA, FLYING AT 1800 MSL AS BUFFER. COM ESTABLISHED WITH MIDWAY RADAR 119.45 AT 11 NM W. THEY VECTORED ME 040 TO STAY N OF MDW, INSTEAD OF DIRECT OVERFLT, AND SAID THE 'WOULD TURN ME EBND LATER'. I RECEIVED A TFC ADVISORY OF AN SMA AT 1600 2 MI ALSO NEBND, NOT IN SIGHT, THEN TOLD ME TO FOLLOW THE EISENHOWER, 3 NM AHEAD. IN THE HAZY CONDITIONS I WAS LOOKING FOR TFC AND VISUALLY NAVIGATING AND BECAME UNCERTAIN OF EXPRESSWAY LOCATION (ACTUALLY ONLY 1 NM AHEAD) VERSUS ANOTHER ROAD, ALL THE WHILE CONCERNED OF NEARBY LOWER TFC. I QUESTIONED THEM 'IF THE EISENHOWER WAS THE ROAD BENEATH ME NOW' TO WHICH I RECEIVED 'AFFIRMATIVE'. I IMMEDIATELY NOTICED MY ALT HAD DEVIATED TO ALMOST 2000 MSL (THERE WAS CONTINUOUS LIGHT TURBULENCE IN THERMAL INSTABILITY) AND AS I WAS DESCENDING BACK TO 1800 I WAS INSTRUCTED TO 'MAINTAIN AT OR BELOW 1700'. MEANWHILE I FOUND MY SMA TFC AT 1600 AND ABOUT 1 MILE. THE REST OF THE FLT WAS UNEVENTFUL. I'M NOT SURE IF MIDWAY RADAR THOUGHT I VIOLATED THE TCA, BUT THEY DID CAUSE SEVERAL PROBLEMS FOR ME. 1) VECTORED ME OUT OF A 3000' TCA FLOOR AREA INTO A 1900' AREA, WITHOUT WARNING OF TCA, NEGATING MY BUFFER ZONE. 2) MISLED ME AS TO DISTANCE OF EXPRESSWAY, CONFUSING THE ISSUE. 3) VECTORED ME INTO A POTENTIAL TFC CONFLICT WITH ANOTHER ACFT GOING THE SAME DIRECTION. IF THEY ARE GOING TO VECTOR US TOWARD A TCA BOUNDARY CHANGE WE OUGHT TO BE NOTIFIED. THIS PROSPECT BOTHERS ME ALMOST AS MUCH AS THE ATC-INITIATED TFC CONFLICT.

Data retrieved from NASA's ASRS site as of August 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.