An air carrier medium large transport climbed in response to a GPWS command.

Attributes
ACN	234802
Time
Date	199302
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : oak
State Reference	CA
Altitude	msl bound lower : 5000 msl bound upper : 8000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sfo
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 220 flight time total : 7000 flight time type : 2100
ASRS Report	234802
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	controller : issued new clearance flight crew : overcame equipment problem flight crew : took evasive action
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation other

Narrative:

Level at 5000 ft on vectors for approach, heading 270 degrees. Aural and visual warning for terrain activated ('terrain, terrain, pull up, pull up'). I called for and pilots simultaneously initiated climb at maximum rate. Leveled off at 8000 ft and notified ATC, who then instructed us to descend back to 5000 ft. ATC notified us that mount diablo may have been the possible cause for the GPWS alert. This could have been a possible collision situation with other IMC traffic in the bay area.

Original NASA ASRS Text

Title: AN ACR MLG CLBED IN RESPONSE TO A GPWS COMMAND.

Narrative: LEVEL AT 5000 FT ON VECTORS FOR APCH, HDG 270 DEGS. AURAL AND VISUAL WARNING FOR TERRAIN ACTIVATED ('TERRAIN, TERRAIN, PULL UP, PULL UP'). I CALLED FOR AND PLTS SIMULTANEOUSLY INITIATED CLB AT MAX RATE. LEVELED OFF AT 8000 FT AND NOTIFIED ATC, WHO THEN INSTRUCTED US TO DSND BACK TO 5000 FT. ATC NOTIFIED US THAT MOUNT DIABLO MAY HAVE BEEN THE POSSIBLE CAUSE FOR THE GPWS ALERT. THIS COULD HAVE BEEN A POSSIBLE COLLISION SIT WITH OTHER IMC TFC IN THE BAY 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.