Airbus on vectors by nct to oak runway 11 experienced GPWS alert at 3100 ft.

Attributes
ACN	602474
Time
Date	200312
Day	Fri
Local Time Of Day	1801 To 2400
Place
State Reference	CA
Altitude	msl bound lower : 3100 msl bound upper : 4500
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : nct.tracon
Operator	common carrier : air carrier
Make Model Name	Airbus Industrie Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 11 other vortac
Flight Phase	descent : approach
Route In Use	approach : instrument precision arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : cfi pilot : atp pilot : commercial
Experience	flight time last 90 days : 60 flight time total : 13000 flight time type : 450
ASRS Report	602474
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	other anomaly other other spatial deviation
Independent Detector	aircraft equipment : gpws other flight crewa
Resolutory Action	flight crew : took evasive action flight crew : overrode automation
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Aircraft Airspace Structure ATC Human Performance
Primary Problem	Ambiguous

Narrative:

Were being radar vectored for ILS runway 11 at oak by norcal approach. Was in level flight in IMC at 3100 ft MSL and 230 KIAS. Egpws (terrain) was being displayed on my (PF) navigation display and highest terrain depicted for the selected range was 2600 ft MSL. Suddenly, we received a GPWS 'pull-up' alert, no red was being displayed visually (no pop-up terrain, obstacle, etc). As I executed the GPWS escape maneuver (an immediate climb), the captain, pfd (primary flight display) registered a radar altitude of 1300 ft AGL. We climbed to an altitude of approximately 4500 ft MSL before terrain warnings ceased and we felt sure we were clear of terrain. Approach queried us as to our altitude and the captain replied that we were responding to a GPWS alert. Eventually descended to our assigned altitude of 3100 ft MSL with no further problems. ATC did not seem very concerned, stated they vectored aircraft through the same area with no problems on a routine basis. However, I know of many aircraft have experienced several GPWS alerts while being vectored in the same area.

Original NASA ASRS Text

Title: AIRBUS ON VECTORS BY NCT TO OAK RWY 11 EXPERIENCED GPWS ALERT AT 3100 FT.

Narrative: WERE BEING RADAR VECTORED FOR ILS RWY 11 AT OAK BY NORCAL APCH. WAS IN LEVEL FLT IN IMC AT 3100 FT MSL AND 230 KIAS. EGPWS (TERRAIN) WAS BEING DISPLAYED ON MY (PF) NAV DISPLAY AND HIGHEST TERRAIN DEPICTED FOR THE SELECTED RANGE WAS 2600 FT MSL. SUDDENLY, WE RECEIVED A GPWS 'PULL-UP' ALERT, NO RED WAS BEING DISPLAYED VISUALLY (NO POP-UP TERRAIN, OBSTACLE, ETC). AS I EXECUTED THE GPWS ESCAPE MANEUVER (AN IMMEDIATE CLB), THE CAPT, PFD (PRIMARY FLT DISPLAY) REGISTERED A RADAR ALT OF 1300 FT AGL. WE CLBED TO AN ALT OF APPROX 4500 FT MSL BEFORE TERRAIN WARNINGS CEASED AND WE FELT SURE WE WERE CLR OF TERRAIN. APCH QUERIED US AS TO OUR ALT AND THE CAPT REPLIED THAT WE WERE RESPONDING TO A GPWS ALERT. EVENTUALLY DSNDED TO OUR ASSIGNED ALT OF 3100 FT MSL WITH NO FURTHER PROBS. ATC DID NOT SEEM VERY CONCERNED, STATED THEY VECTORED ACFT THROUGH THE SAME AREA WITH NO PROBS ON A ROUTINE BASIS. HOWEVER, I KNOW OF MANY ACFT HAVE EXPERIENCED SEVERAL GPWS ALERTS WHILE BEING VECTORED IN THE SAME AREA.

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.