Narrative:

Flight experienced a GPWS alert. The aircraft was on a base leg descending from 5000 ft to 3800 ft. The controller had issued a vector of 180 degrees for a dogleg and another vector to intercept the localizer 27 approach to san. The GPWS alert sounded, the captain disconnected autoplt and climbed approximately 1500 ft or until the GPWS warning ceased. Approach and landing in san were normal. During turnaround, the captain talked with the supervisor and he informed me this happens all the time and has occurred routinely for many yrs. I asked him if he was aware of our procedures for a GPWS alert. He indicated he was aware of our procedures. I told him it is very frightening for the crew and passenger because it's a very aggressive maneuver. The supervisor indicated the point of concern is mount san miguel located 1 1/2 - 2 mi north of swatt intersection on the localizer 27 approach to san. He told me to contact our safety folks to contact their safety folks and told me a solution could be worked out. Callback conversation with reporter revealed the following information: reporter learned several facts from a call to a facility person. The GPWS warnings occur a couple times a day. The facility is required to log all GPWS reports. The facility will occasionally get a low altitude alert on an aircraft in this area. The GPWS warnings generally occur when an aircraft is on a 4 mi base leg-to- final approach and is believed to be caused by the angle of descent when descending from 5000 ft to 3800 ft. Facility person claims it does occur on occasion with aircraft descending inbound from the north and from the east. This person indicated there have been no recent changes to the MVA procedures for this area. Facility person did not know if the GPWS reports involved MD80 type aircraft.

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Original NASA ASRS Text

Title: RPTR CLAIMS THEY RECEIVED A GPWS WHILE DSNDING FROM 5000 FT TO 3800 FT ON A VECTOR HDG TO INTERCEPT THE LOC FOR RWY 27.

Narrative: FLT EXPERIENCED A GPWS ALERT. THE ACFT WAS ON A BASE LEG DSNDING FROM 5000 FT TO 3800 FT. THE CTLR HAD ISSUED A VECTOR OF 180 DEGS FOR A DOGLEG AND ANOTHER VECTOR TO INTERCEPT THE LOC 27 APCH TO SAN. THE GPWS ALERT SOUNDED, THE CAPT DISCONNECTED AUTOPLT AND CLBED APPROX 1500 FT OR UNTIL THE GPWS WARNING CEASED. APCH AND LNDG IN SAN WERE NORMAL. DURING TURNAROUND, THE CAPT TALKED WITH THE SUPVR AND HE INFORMED ME THIS HAPPENS ALL THE TIME AND HAS OCCURRED ROUTINELY FOR MANY YRS. I ASKED HIM IF HE WAS AWARE OF OUR PROCS FOR A GPWS ALERT. HE INDICATED HE WAS AWARE OF OUR PROCS. I TOLD HIM IT IS VERY FRIGHTENING FOR THE CREW AND PAX BECAUSE IT'S A VERY AGGRESSIVE MANEUVER. THE SUPVR INDICATED THE POINT OF CONCERN IS MOUNT SAN MIGUEL LOCATED 1 1/2 - 2 MI N OF SWATT INTXN ON THE LOC 27 APCH TO SAN. HE TOLD ME TO CONTACT OUR SAFETY FOLKS TO CONTACT THEIR SAFETY FOLKS AND TOLD ME A SOLUTION COULD BE WORKED OUT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR LEARNED SEVERAL FACTS FROM A CALL TO A FACILITY PERSON. THE GPWS WARNINGS OCCUR A COUPLE TIMES A DAY. THE FACILITY IS REQUIRED TO LOG ALL GPWS RPTS. THE FACILITY WILL OCCASIONALLY GET A LOW ALT ALERT ON AN ACFT IN THIS AREA. THE GPWS WARNINGS GENERALLY OCCUR WHEN AN ACFT IS ON A 4 MI BASE LEG-TO- FINAL APCH AND IS BELIEVED TO BE CAUSED BY THE ANGLE OF DSCNT WHEN DSNDING FROM 5000 FT TO 3800 FT. FACILITY PERSON CLAIMS IT DOES OCCUR ON OCCASION WITH ACFT DSNDING INBOUND FROM THE N AND FROM THE E. THIS PERSON INDICATED THERE HAVE BEEN NO RECENT CHANGES TO THE MVA PROCS FOR THIS AREA. FACILITY PERSON DID NOT KNOW IF THE GPWS RPTS INVOLVED MD80 TYPE ACFT.

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.