Narrative:

On a VFR flight from mry to oak, I was vectored by bay approach control from south of sjc to oak. When I was approximately 4 1/2 NM northeast of moffett field at 5500, bay cleared me direct to oak to cross 6 mi south of oak VOR at or above 2000 ft. At approximately 10 NM from oak VOR on the 118 degree radial, bay approach instructed me to contact oak tower. Before I could establish contact with oak tower, I inadvertently assumed my 2000 ft at or above restriction 6 mi south of oak was lifted since I had been turned over to the tower and that I could begin a VFR descent in preparation for a straight- in approach to runway 27R at oak (I should have confirmed my assumption with bay approach before I began a descent). When I contacted oak tower, they advised me that, in the future, I should cross the hwd airport area above 2000 ft. At the time I contacted the tower, I was at an altitude of 1500 ft. I climbed immediately to 2000 ft. Oak tower indicated no traffic conflict, but advised me of an aircraft which was on low final approach to runway 10R at hwd. I had visual contact with the traffic. Since the pattern altitude at hwd for runway 10R is 650 ft and for runway 10L is 850 ft, no conflict with other pattern traffic would have occurred. I acknowledged my mistake and the tower indicated no further problem. I received vectors to runway 27R for a straight-in landing.

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Original NASA ASRS Text

Title: PLT OF AN SMA SEL PVT ACFT DSNDED EARLY DURING A VFR FLT INTO AN ARSA (C) AIRSPACE CAUSING ERRONEOUS PENETRATION OF AN ATA (D) AIRSPACE.

Narrative: ON A VFR FLT FROM MRY TO OAK, I WAS VECTORED BY BAY APCH CTL FROM S OF SJC TO OAK. WHEN I WAS APPROX 4 1/2 NM NE OF MOFFETT FIELD AT 5500, BAY CLRED ME DIRECT TO OAK TO CROSS 6 MI S OF OAK VOR AT OR ABOVE 2000 FT. AT APPROX 10 NM FROM OAK VOR ON THE 118 DEG RADIAL, BAY APCH INSTRUCTED ME TO CONTACT OAK TWR. BEFORE I COULD ESTABLISH CONTACT WITH OAK TWR, I INADVERTENTLY ASSUMED MY 2000 FT AT OR ABOVE RESTRICTION 6 MI S OF OAK WAS LIFTED SINCE I HAD BEEN TURNED OVER TO THE TWR AND THAT I COULD BEGIN A VFR DSCNT IN PREPARATION FOR A STRAIGHT- IN APCH TO RWY 27R AT OAK (I SHOULD HAVE CONFIRMED MY ASSUMPTION WITH BAY APCH BEFORE I BEGAN A DSCNT). WHEN I CONTACTED OAK TWR, THEY ADVISED ME THAT, IN THE FUTURE, I SHOULD CROSS THE HWD ARPT AREA ABOVE 2000 FT. AT THE TIME I CONTACTED THE TWR, I WAS AT AN ALT OF 1500 FT. I CLBED IMMEDIATELY TO 2000 FT. OAK TWR INDICATED NO TFC CONFLICT, BUT ADVISED ME OF AN ACFT WHICH WAS ON LOW FINAL APCH TO RWY 10R AT HWD. I HAD VISUAL CONTACT WITH THE TFC. SINCE THE PATTERN ALT AT HWD FOR RWY 10R IS 650 FT AND FOR RWY 10L IS 850 FT, NO CONFLICT WITH OTHER PATTERN TFC WOULD HAVE OCCURRED. I ACKNOWLEDGED MY MISTAKE AND THE TWR INDICATED NO FURTHER PROB. I RECEIVED VECTORS TO RWY 27R FOR A STRAIGHT-IN LNDG.

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.