Narrative:

Approximately 11 DME southwest of sjc VOR, IMC conditions, 4500 ft MSL, turning from 140 degrees to 360 degrees we received a GPWS warning -- 'terrain, terrain.' captain started pull-up and power increase. At second activation of GPWS warning, captain pulled aircraft pitch to stick shaker and advanced power levers to go around power. We climbed approximately 2000 ft and notified ATC of deviation. We re-entered downwind and descended for an uneventful approach and landing. We were unable to give a PA to the passenger or advise the flight attendants due to time constraints. After landing, captain called bay TRACON supervisor. Supervisor stated that our altitude was 400 ft above his MVA for the sector and that other airline's aircraft had reported similar GPWS warnings. This may indicate a calibration problem with our avionics. Since we were IMC, we had to treat the GPWS warning as valid. We did our best to reassure and explain to the passenger, as they were deplaning, why we had to maneuver the aircraft so abruptly.

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Original NASA ASRS Text

Title: THE FLC EXPERIENCED 2 GPWS 'TERRAIN, TERRAIN' WARNINGS. THE FLC BEING IMC COMPLIED WITH THE APPROPRIATE GPWS WARNING PROCS. THE TFC CTLR STATED THE FLT WAS 400 FT ABOVE THE MINIMUM VECTORING ALT. THE TFC CTLR STATED ANOTHER AIRLINE ALSO EXPERIENCED THE GPWS WARNING THAT DAY.

Narrative: APPROX 11 DME SW OF SJC VOR, IMC CONDITIONS, 4500 FT MSL, TURNING FROM 140 DEGS TO 360 DEGS WE RECEIVED A GPWS WARNING -- 'TERRAIN, TERRAIN.' CAPT STARTED PULL-UP AND PWR INCREASE. AT SECOND ACTIVATION OF GPWS WARNING, CAPT PULLED ACFT PITCH TO STICK SHAKER AND ADVANCED PWR LEVERS TO GAR PWR. WE CLBED APPROX 2000 FT AND NOTIFIED ATC OF DEV. WE RE-ENTERED DOWNWIND AND DSNDED FOR AN UNEVENTFUL APCH AND LNDG. WE WERE UNABLE TO GIVE A PA TO THE PAX OR ADVISE THE FLT ATTENDANTS DUE TO TIME CONSTRAINTS. AFTER LNDG, CAPT CALLED BAY TRACON SUPVR. SUPVR STATED THAT OUR ALT WAS 400 FT ABOVE HIS MVA FOR THE SECTOR AND THAT OTHER AIRLINE'S ACFT HAD RPTED SIMILAR GPWS WARNINGS. THIS MAY INDICATE A CALIBRATION PROB WITH OUR AVIONICS. SINCE WE WERE IMC, WE HAD TO TREAT THE GPWS WARNING AS VALID. WE DID OUR BEST TO REASSURE AND EXPLAIN TO THE PAX, AS THEY WERE DEPLANING, WHY WE HAD TO MANEUVER THE ACFT SO ABRUPTLY.

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.