Narrative:

Descending into sjc from the northwest. Approach kept us high downwind (10000 ft MSL). After passing abeam the airport, they cleared us to 8000 ft, which was then followed by cleared for fairgrounds visual for runway 30L. This charted visual shows a turn to base leg at the sjc 176 degree radial. As we were about 3000 ft above the normal altitude at this point, I elected to extend downwind to lose altitude. As we descended downwind several mi, captain said it looked good for a turn back to the runway, which I did. We intercepted final (at about 10 mi) and I flew the GS toward the runway. At about 7 mi on final, approach asked us about our extended pattern. Captain said we needed it for descent. Captain then told me I needed to maintain 2500 ft until 6.6 DME from sjc. At about this time, we were at 1750 ft MSL as I was following the GS. As we were on final, I continued to uneventful touchdown. On the ground, we discussed the approach. The verbal description on the charted visual says to 'turn final no closer than 6.6 DME sjc at or above 2500 ft.' the confusion exists because the plan view shows 2500 ft at 6.6 sjc leading you to believe that you need to cross that point at or above 2500 ft. However, the sjc VOR is 1.6 NM northwest of the end of the runway, so you would only have 6.6 NM - 1.6 NM = 5.0 NM to lose 2500 ft which is much greater than the recommended 3:1 descent ratio. It would have been beneficial if I had captain inform ATC that we were extending downwind for descent. The charted visual is not clearly defined as to their intent. Callback conversation with reporter revealed the following information: the reporter does not know why TRACON kept his aircraft high for so long, but this created an uncomfortable situation for the turn in. He understands the term 'recommended' on the downwind and base legs, but does not understand the term 'should' for the altitude over the fairgrounds. The procedure is designed for noise abatement at saratoga and los gatos. It does not comply with normal 3 degree GS and stabilized approach criteria. He believes that publishing the ILS 30L overlying this procedure invites pilots to descend on a normal vertical path to intercept the GS at 6.6 DME, not at the 'should' or 'recommended' altitude or 2500 ft. He thinks that the TRACON controller might have been concerned that his aircraft was flying southeast farther than usual and descending into rising terrain.

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Original NASA ASRS Text

Title: AN ACR MD80 PLT WAS BELOW THE RECOMMENDED ALT ON THE FAIRGROUNDS VISUAL RWY 30L APCH TO SJC BUT ON THE ILS GS. HIS ACR REQUIRES A STABILIZED APCH AND BEING AT THE RECOMMENDED ALT INCREASES THE GS ANGLE WELL ABOVE THE NORMAL 3 DEG.

Narrative: DSNDING INTO SJC FROM THE NW. APCH KEPT US HIGH DOWNWIND (10000 FT MSL). AFTER PASSING ABEAM THE ARPT, THEY CLRED US TO 8000 FT, WHICH WAS THEN FOLLOWED BY CLRED FOR FAIRGROUNDS VISUAL FOR RWY 30L. THIS CHARTED VISUAL SHOWS A TURN TO BASE LEG AT THE SJC 176 DEG RADIAL. AS WE WERE ABOUT 3000 FT ABOVE THE NORMAL ALT AT THIS POINT, I ELECTED TO EXTEND DOWNWIND TO LOSE ALT. AS WE DSNDED DOWNWIND SEVERAL MI, CAPT SAID IT LOOKED GOOD FOR A TURN BACK TO THE RWY, WHICH I DID. WE INTERCEPTED FINAL (AT ABOUT 10 MI) AND I FLEW THE GS TOWARD THE RWY. AT ABOUT 7 MI ON FINAL, APCH ASKED US ABOUT OUR EXTENDED PATTERN. CAPT SAID WE NEEDED IT FOR DSCNT. CAPT THEN TOLD ME I NEEDED TO MAINTAIN 2500 FT UNTIL 6.6 DME FROM SJC. AT ABOUT THIS TIME, WE WERE AT 1750 FT MSL AS I WAS FOLLOWING THE GS. AS WE WERE ON FINAL, I CONTINUED TO UNEVENTFUL TOUCHDOWN. ON THE GND, WE DISCUSSED THE APCH. THE VERBAL DESCRIPTION ON THE CHARTED VISUAL SAYS TO 'TURN FINAL NO CLOSER THAN 6.6 DME SJC AT OR ABOVE 2500 FT.' THE CONFUSION EXISTS BECAUSE THE PLAN VIEW SHOWS 2500 FT AT 6.6 SJC LEADING YOU TO BELIEVE THAT YOU NEED TO CROSS THAT POINT AT OR ABOVE 2500 FT. HOWEVER, THE SJC VOR IS 1.6 NM NW OF THE END OF THE RWY, SO YOU WOULD ONLY HAVE 6.6 NM - 1.6 NM = 5.0 NM TO LOSE 2500 FT WHICH IS MUCH GREATER THAN THE RECOMMENDED 3:1 DSCNT RATIO. IT WOULD HAVE BEEN BENEFICIAL IF I HAD CAPT INFORM ATC THAT WE WERE EXTENDING DOWNWIND FOR DSCNT. THE CHARTED VISUAL IS NOT CLRLY DEFINED AS TO THEIR INTENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR DOES NOT KNOW WHY TRACON KEPT HIS ACFT HIGH FOR SO LONG, BUT THIS CREATED AN UNCOMFORTABLE SIT FOR THE TURN IN. HE UNDERSTANDS THE TERM 'RECOMMENDED' ON THE DOWNWIND AND BASE LEGS, BUT DOES NOT UNDERSTAND THE TERM 'SHOULD' FOR THE ALT OVER THE FAIRGROUNDS. THE PROC IS DESIGNED FOR NOISE ABATEMENT AT SARATOGA AND LOS GATOS. IT DOES NOT COMPLY WITH NORMAL 3 DEG GS AND STABILIZED APCH CRITERIA. HE BELIEVES THAT PUBLISHING THE ILS 30L OVERLYING THIS PROC INVITES PLTS TO DSND ON A NORMAL VERT PATH TO INTERCEPT THE GS AT 6.6 DME, NOT AT THE 'SHOULD' OR 'RECOMMENDED' ALT OR 2500 FT. HE THINKS THAT THE TRACON CTLR MIGHT HAVE BEEN CONCERNED THAT HIS ACFT WAS FLYING SE FARTHER THAN USUAL AND DSNDING INTO RISING TERRAIN.

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.