Narrative:

On IFR flight plan lax to apc: gmn ave oak sgd. After ATC handoff from ZLA to ZOA, ZOA described us early, handoff to stockton approach, back to ZOA prior to apc (napa) area. Minor rerte which still included sgd (skaggs 1 VOR). Approaching sgd from east, ZOA asked if we had apc in sight. At a point approximately south of apc, we indicated we had airport in sight. ZOA assigned a heading of 260 degrees, maintain 3000 ft for traffic at 11 O'clock position. We sighted traffic (high wing single engine) as it passed beneath us from approximately 11-4 O'clock position. ZOA then cleared us for visual approach to apc and to change to apc CTAF. We began right turn from modified downwind approximately 4 mi southwest of airport to base and final aligned with runway 6 (runway in use). On CTAF frequency, we heard tower working multiple aircraft in pattern. Upon establishing final, 2-3 mi from airport, we saw at least 2 single engine aircraft between us and airport and heard tower talking to another one on left base. We also passed to the left another high wing that tower was not talking to. At this point it became obvious that our continued straight-in would not work, and about the same time tower came to same conclusion, issuing 'maintain 1500 ft (we were descending through about 1300 ft) fly the overhead approach, right downwind for runway 6.' we climbed back to 1500 ft, flew as directed, landed and taxied to parking. Upon entering FBO, was given message that tower wanted a call. Their question was the result of a ZOA inquiry about why we had done a '360 over the VOR.' responded that only '360' was overhead pattern at tower's request. Then given message to call ZOA. Center cause of concern was a loss of separation alarm between 2 IFR aircraft. These were apparently us and a C172 on the VOR approach. We indicated we were in VMC conditions on visual approach with all significant traffic in sight under CTAF control. My perception is that the 'conflict' C172 was the aircraft that passed under us as we were held at 3000 ft and again on right downwind on final. We had that aircraft in sight on both occasions.

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Original NASA ASRS Text

Title: FLC OF A CPR JET WAS INSTRUCTED BY TWR TO DO A 360 DEG TURN FOR TFC PATTERN SPACING AFTER BEING HANDED OFF BY ARTCC CTLR FOR A VISUAL APCH. HE WAS THEN SUBSEQUENTLY ASKED BY ARTCC WHY THEY DID A 360 DEG TURN.

Narrative: ON IFR FLT PLAN LAX TO APC: GMN AVE OAK SGD. AFTER ATC HDOF FROM ZLA TO ZOA, ZOA DESCRIBED US EARLY, HDOF TO STOCKTON APCH, BACK TO ZOA PRIOR TO APC (NAPA) AREA. MINOR RERTE WHICH STILL INCLUDED SGD (SKAGGS 1 VOR). APCHING SGD FROM E, ZOA ASKED IF WE HAD APC IN SIGHT. AT A POINT APPROX S OF APC, WE INDICATED WE HAD ARPT IN SIGHT. ZOA ASSIGNED A HDG OF 260 DEGS, MAINTAIN 3000 FT FOR TFC AT 11 O'CLOCK POS. WE SIGHTED TFC (HIGH WING SINGLE ENG) AS IT PASSED BENEATH US FROM APPROX 11-4 O'CLOCK POS. ZOA THEN CLRED US FOR VISUAL APCH TO APC AND TO CHANGE TO APC CTAF. WE BEGAN R TURN FROM MODIFIED DOWNWIND APPROX 4 MI SW OF ARPT TO BASE AND FINAL ALIGNED WITH RWY 6 (RWY IN USE). ON CTAF FREQ, WE HEARD TWR WORKING MULTIPLE ACFT IN PATTERN. UPON ESTABLISHING FINAL, 2-3 MI FROM ARPT, WE SAW AT LEAST 2 SINGLE ENG ACFT BTWN US AND ARPT AND HEARD TWR TALKING TO ANOTHER ONE ON L BASE. WE ALSO PASSED TO THE L ANOTHER HIGH WING THAT TWR WAS NOT TALKING TO. AT THIS POINT IT BECAME OBVIOUS THAT OUR CONTINUED STRAIGHT-IN WOULD NOT WORK, AND ABOUT THE SAME TIME TWR CAME TO SAME CONCLUSION, ISSUING 'MAINTAIN 1500 FT (WE WERE DSNDING THROUGH ABOUT 1300 FT) FLY THE OVERHEAD APCH, R DOWNWIND FOR RWY 6.' WE CLBED BACK TO 1500 FT, FLEW AS DIRECTED, LANDED AND TAXIED TO PARKING. UPON ENTERING FBO, WAS GIVEN MESSAGE THAT TWR WANTED A CALL. THEIR QUESTION WAS THE RESULT OF A ZOA INQUIRY ABOUT WHY WE HAD DONE A '360 OVER THE VOR.' RESPONDED THAT ONLY '360' WAS OVERHEAD PATTERN AT TWR'S REQUEST. THEN GIVEN MESSAGE TO CALL ZOA. CENTER CAUSE OF CONCERN WAS A LOSS OF SEPARATION ALARM BTWN 2 IFR ACFT. THESE WERE APPARENTLY US AND A C172 ON THE VOR APCH. WE INDICATED WE WERE IN VMC CONDITIONS ON VISUAL APCH WITH ALL SIGNIFICANT TFC IN SIGHT UNDER CTAF CTL. MY PERCEPTION IS THAT THE 'CONFLICT' C172 WAS THE ACFT THAT PASSED UNDER US AS WE WERE HELD AT 3000 FT AND AGAIN ON R DOWNWIND ON FINAL. WE HAD THAT ACFT IN SIGHT ON BOTH OCCASIONS.

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.