Narrative:

Already behind the curve due to a late descent at papee on the el nido 5 arrival. Told to turn and intercept 118 degree radial of sjc. Handed off to approach who descended us to 5000 ft and told us to go to gilro, which was abeam. This caused some confusion while we sorted out where we were as we had extended FMS onto radial. He canceled this vector, said no problem, and told us to maintain 5000 ft until on a segment of the approach. This is where I might have messed up thinking we were on a segment outside of finor. I believe the segment does not begin until finor. We left 5000 ft for 4300 ft, I believe 3-5 mi too early, while established on the 118 degree radial. Several things added to this. We were using the VNAV procedure VFR for training. I was in VOR mode as a back-up. First officer was in navigation mode. The vector to gilro threw us off -- similarly to the cali disaster -- as it was XA00 body time, but what had me way behind was my recency of experience having flown once in april -- not at all in march -- and once in february. Lots of good lessons here. Thanks for this program. Did not discuss incident with the approach controller.

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Original NASA ASRS Text

Title: A B737 CREW, ON APCH TO SJC, COMMENCED DSCNT OUT OF THEIR ASSIGNED ALT BEFORE BEING 'ON A SEGMENT OF THE APCH,' AS ATC HAD INSTRUCTED.

Narrative: ALREADY BEHIND THE CURVE DUE TO A LATE DSCNT AT PAPEE ON THE EL NIDO 5 ARR. TOLD TO TURN AND INTERCEPT 118 DEG RADIAL OF SJC. HANDED OFF TO APCH WHO DSNDED US TO 5000 FT AND TOLD US TO GO TO GILRO, WHICH WAS ABEAM. THIS CAUSED SOME CONFUSION WHILE WE SORTED OUT WHERE WE WERE AS WE HAD EXTENDED FMS ONTO RADIAL. HE CANCELED THIS VECTOR, SAID NO PROB, AND TOLD US TO MAINTAIN 5000 FT UNTIL ON A SEGMENT OF THE APCH. THIS IS WHERE I MIGHT HAVE MESSED UP THINKING WE WERE ON A SEGMENT OUTSIDE OF FINOR. I BELIEVE THE SEGMENT DOES NOT BEGIN UNTIL FINOR. WE LEFT 5000 FT FOR 4300 FT, I BELIEVE 3-5 MI TOO EARLY, WHILE ESTABLISHED ON THE 118 DEG RADIAL. SEVERAL THINGS ADDED TO THIS. WE WERE USING THE VNAV PROC VFR FOR TRAINING. I WAS IN VOR MODE AS A BACK-UP. FO WAS IN NAV MODE. THE VECTOR TO GILRO THREW US OFF -- SIMILARLY TO THE CALI DISASTER -- AS IT WAS XA00 BODY TIME, BUT WHAT HAD ME WAY BEHIND WAS MY RECENCY OF EXPERIENCE HAVING FLOWN ONCE IN APRIL -- NOT AT ALL IN MARCH -- AND ONCE IN FEBRUARY. LOTS OF GOOD LESSONS HERE. THANKS FOR THIS PROGRAM. DID NOT DISCUSS INCIDENT WITH THE APCH CTLR.

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.