A super MD80 flight crew received 2 GPWS terrain warnings in an area well above the MVA near sea.

Attributes
ACN	443771
Time
Date	199907
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : sea.airport
State Reference	WA
Altitude	msl bound lower : 5000 msl bound upper : 7900
Environment
Flight Conditions	Mixed
Weather Elements	Rain
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : s46.tracon
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : approach
Route In Use	arrival star : chins11
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	443771
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
ASRS Report	443760
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	aircraft equipment : gpws
Resolutory Action	flight crew : took precautionary avoidance action
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

ATC facility: sea approach control. Location: 12 NM northeast sea VOR, 116.8. Radar vectors downwind for ILS runway 16R. After deviating off the chins 2 arrival for rainshowers, we were descending through approximately 6000 ft for 5000 ft configured flaps 15 degrees, speed 210 KIAS with red rain radar returns under our flight lvl when we got a GPWS 'terrain' warning. I initiated an escape and the first officer advised approach control with the GPWS in the radio backgnd. Out of approximately 7500 ft it ceased but recurred again at approximately 7900 ft. At 9600 ft it ws out and the ATC controller confirmed the MVA under us less than 3000 ft. The first warning was of 20-30 seconds duration and the second of 10-15 seconds. It was night in the WX with ATIS 4 scattered, 8 overcast 4 SM rainshowers. Subsequent landing was uneventful. Note the flaps 15 degrees confign versus speed brakes helped as the lift and drag versus pure drag immediately put us on the up escalator out of the sector MSA of 6200 ft already prebriefed for the approach.

Original NASA ASRS Text

Title: A SUPER MD80 FLC RECEIVED 2 GPWS TERRAIN WARNINGS IN AN AREA WELL ABOVE THE MVA NEAR SEA.

Narrative: ATC FACILITY: SEA APCH CTL. LOCATION: 12 NM NE SEA VOR, 116.8. RADAR VECTORS DOWNWIND FOR ILS RWY 16R. AFTER DEVIATING OFF THE CHINS 2 ARR FOR RAINSHOWERS, WE WERE DSNDING THROUGH APPROX 6000 FT FOR 5000 FT CONFIGURED FLAPS 15 DEGS, SPD 210 KIAS WITH RED RAIN RADAR RETURNS UNDER OUR FLT LVL WHEN WE GOT A GPWS 'TERRAIN' WARNING. I INITIATED AN ESCAPE AND THE FO ADVISED APCH CTL WITH THE GPWS IN THE RADIO BACKGND. OUT OF APPROX 7500 FT IT CEASED BUT RECURRED AGAIN AT APPROX 7900 FT. AT 9600 FT IT WS OUT AND THE ATC CTLR CONFIRMED THE MVA UNDER US LESS THAN 3000 FT. THE FIRST WARNING WAS OF 20-30 SECONDS DURATION AND THE SECOND OF 10-15 SECONDS. IT WAS NIGHT IN THE WX WITH ATIS 4 SCATTERED, 8 OVCST 4 SM RAINSHOWERS. SUBSEQUENT LNDG WAS UNEVENTFUL. NOTE THE FLAPS 15 DEGS CONFIGN VERSUS SPD BRAKES HELPED AS THE LIFT AND DRAG VERSUS PURE DRAG IMMEDIATELY PUT US ON THE UP ESCALATOR OUT OF THE SECTOR MSA OF 6200 FT ALREADY PREBRIEFED FOR 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.