A320 flight crew has GPWS 'GS' warning during CAT III approach to kiad.

Attributes
ACN	574675
Time
Date	200302
Day	Sun
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : iad.airport
State Reference	VA
Altitude	agl bound lower : 0 agl bound upper : 1000
Environment
Light	Night
Aircraft 1
Controlling Facilities	tower : iad.tower
Operator	common carrier : air carrier
Make Model Name	A320
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 1r other
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
ASRS Report	574675
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	non adherence : company policies non adherence : published procedure other anomaly
Independent Detector	aircraft equipment : gpws other flight crewa other flight crewb
Resolutory Action	none taken : anomaly accepted
Supplementary
Problem Areas	Flight Crew Human Performance Weather Aircraft
Primary Problem	Flight Crew Human Performance

Narrative:

WX kiad -- RVR runway 1R, 3000 ft variable 2000 ft. Wind on surface calm. Inside tille LOM quartering tailwind approximately 24 KTS. Approach -- crew fully briefed CAT III autoland per SOP. Gear was down prior to tille. Aircraft stabilized by 1000 ft afe. Altitude between 1000 ft and 500 ft afe autoplts 1 and 2 were compensating for shifting winds. We got 1 DOT below GS and got low level GPWS GS warning. Per FM 6-188 paragraph 4. We monitored the deviation and saw the autoplts were correcting. I, the first officer, had the approach lights in sight at that time. The autoplt was tracking the GS all the way to touchdown. We completed the autoland and did not go around per SOP for GPWS GS warning below 1000 ft afe.

Original NASA ASRS Text

Title: A320 FLT CREW HAS GPWS 'GS' WARNING DURING CAT III APCH TO KIAD.

Narrative: WX KIAD -- RVR RWY 1R, 3000 FT VARIABLE 2000 FT. WIND ON SURFACE CALM. INSIDE TILLE LOM QUARTERING TAILWIND APPROX 24 KTS. APCH -- CREW FULLY BRIEFED CAT III AUTOLAND PER SOP. GEAR WAS DOWN PRIOR TO TILLE. ACFT STABILIZED BY 1000 FT AFE. ALT BTWN 1000 FT AND 500 FT AFE AUTOPLTS 1 AND 2 WERE COMPENSATING FOR SHIFTING WINDS. WE GOT 1 DOT BELOW GS AND GOT LOW LEVEL GPWS GS WARNING. PER FM 6-188 PARAGRAPH 4. WE MONITORED THE DEV AND SAW THE AUTOPLTS WERE CORRECTING. I, THE FO, HAD THE APCH LIGHTS IN SIGHT AT THAT TIME. THE AUTOPLT WAS TRACKING THE GS ALL THE WAY TO TOUCHDOWN. WE COMPLETED THE AUTOLAND AND DID NOT GO AROUND PER SOP FOR GPWS GS WARNING BELOW 1000 FT AFE.

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.