Narrative:

On a recent IFR flight plan flight in VFR conditions, I was being vectored to the final approach course for lvk and was advised to maintain 3300 to footo intersection. My safety pilot could see a lot of VFR traffic in the area and at about 8 NM east of the tcy airport, I descended to 2800 to avoid a potential conflict. The problem is that I did not notify approach of my intentions and the already busy controller asked if I was initiating the descent early, mistaking tcy for lvk. To complicate matters, I removed my hood and saw the airport's runway 25 directly in front and below! For a 'split-second' (mental transition to VFR), I lost track of footo intersection and, in a hurried response to the controller's query, replied, 'I must have' (confused tcy with lvk). It took a few more seconds to verify footo on #2 navigation and I told the controller we were climbing back to 3300 -- but without explanation. A short time later, the controller had to vector us around another conflicting VFR aircraft maneuvering through our flight path. With this out of the way, we returned to course and competed an ILS approach to lvk. Lesson learned -- it is more difficult to fly IFR in crowded VFR conditions, trying to see and avoid (controller advised and not advised) traffic and comply with IFR responsibilities. Certainly, we should have told the controller the reason for our altitude deviation when time permitted.

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Original NASA ASRS Text

Title: ALTDEV EXCURSION FROM ASSIGNED DUE TO EVASIVE ACTION DSCNT TO AVOID VFR XING TFC. LOTS OF UNKNOWN VFR TFC IN AREA.

Narrative: ON A RECENT IFR FLT PLAN FLT IN VFR CONDITIONS, I WAS BEING VECTORED TO THE FINAL APCH COURSE FOR LVK AND WAS ADVISED TO MAINTAIN 3300 TO FOOTO INTXN. MY SAFETY PLT COULD SEE A LOT OF VFR TFC IN THE AREA AND AT ABOUT 8 NM E OF THE TCY ARPT, I DSNDED TO 2800 TO AVOID A POTENTIAL CONFLICT. THE PROB IS THAT I DID NOT NOTIFY APCH OF MY INTENTIONS AND THE ALREADY BUSY CTLR ASKED IF I WAS INITIATING THE DSCNT EARLY, MISTAKING TCY FOR LVK. TO COMPLICATE MATTERS, I REMOVED MY HOOD AND SAW THE ARPT'S RWY 25 DIRECTLY IN FRONT AND BELOW! FOR A 'SPLIT-SECOND' (MENTAL TRANSITION TO VFR), I LOST TRACK OF FOOTO INTXN AND, IN A HURRIED RESPONSE TO THE CTLR'S QUERY, REPLIED, 'I MUST HAVE' (CONFUSED TCY WITH LVK). IT TOOK A FEW MORE SECONDS TO VERIFY FOOTO ON #2 NAV AND I TOLD THE CTLR WE WERE CLBING BACK TO 3300 -- BUT WITHOUT EXPLANATION. A SHORT TIME LATER, THE CTLR HAD TO VECTOR US AROUND ANOTHER CONFLICTING VFR ACFT MANEUVERING THROUGH OUR FLT PATH. WITH THIS OUT OF THE WAY, WE RETURNED TO COURSE AND COMPETED AN ILS APCH TO LVK. LESSON LEARNED -- IT IS MORE DIFFICULT TO FLY IFR IN CROWDED VFR CONDITIONS, TRYING TO SEE AND AVOID (CTLR ADVISED AND NOT ADVISED) TFC AND COMPLY WITH IFR RESPONSIBILITIES. CERTAINLY, WE SHOULD HAVE TOLD THE CTLR THE REASON FOR OUR ALTDEV WHEN TIME PERMITTED.

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.