Medium large transport on approach responds twice to GPWS warnings.

Attributes
ACN	288834
Time
Date	199411
Day	Wed
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : slc
State Reference	UT
Altitude	msl bound lower : 8000 msl bound upper : 9000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : slc tower : lbb
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent : approach other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : atp
Experience	flight time last 90 days : 180 flight time total : 3900 flight time type : 1400
ASRS Report	288834
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
Resolutory Action	controller : issued new clearance flight crew : took evasive action
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Air carrier flight, on approach to slc. Radar vectors on left downwind of 175 degrees at 8000 ft received terrain warning. Captain initiated a pullup and applied power. I called slc approach and told them we were climbing due to a terrain warning. IFR at the time. Captain leveled at 9000 ft. ATC said we were clear of all obstacles gave us a left turn and descent back down to 8000 ft. On modified base had another terrain warning and captain climbed to 8300 ft and I notified approach. Again they assured us we were well clear of all obstacles, issued descent back to 8000 ft from which we completed the approach.

Original NASA ASRS Text

Title: MLG ON APCH RESPONDS TWICE TO GPWS WARNINGS.

Narrative: ACR FLT, ON APCH TO SLC. RADAR VECTORS ON L DOWNWIND OF 175 DEGS AT 8000 FT RECEIVED TERRAIN WARNING. CAPT INITIATED A PULLUP AND APPLIED PWR. I CALLED SLC APCH AND TOLD THEM WE WERE CLBING DUE TO A TERRAIN WARNING. IFR AT THE TIME. CAPT LEVELED AT 9000 FT. ATC SAID WE WERE CLR OF ALL OBSTACLES GAVE US A L TURN AND DSCNT BACK DOWN TO 8000 FT. ON MODIFIED BASE HAD ANOTHER TERRAIN WARNING AND CAPT CLBED TO 8300 FT AND I NOTIFIED APCH. AGAIN THEY ASSURED US WE WERE WELL CLR OF ALL OBSTACLES, ISSUED DSCNT BACK TO 8000 FT FROM WHICH WE COMPLETED THE APCH.

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.