Large transport received false GPWS while approaching the lax area.

Attributes
ACN	233843
Time
Date	199302
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : lax
State Reference	CA
Altitude	msl bound lower : 8500 msl bound upper : 8900
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : lax
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 163 flight time total : 8660 flight time type : 3245
ASRS Report	233843
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

There were large areas of light to moderate rain showers around the lax area. Our flight had been cleared to descend out of 10000 ft to 7000 ft on a 230 degree heading by lax approach control. At about 8500 ft and in a 1200 FPM descent in a moderate rain shower, the GPWS sounded the 'whoop, whoop, pull up' with the red warning lights, then 'terrain, terrain, too low gear, too low flap.' the descent was stopped and a slight climb was initiated to 8900 ft. The warnings stopped and the descent was resumed with no further warnings. I suspect this was caused by the effect of the rain shower on the GPWS. No other causes were apparent.

Original NASA ASRS Text

Title: LGT RECEIVED FALSE GPWS WHILE APCHING THE LAX AREA.

Narrative: THERE WERE LARGE AREAS OF LIGHT TO MODERATE RAIN SHOWERS AROUND THE LAX AREA. OUR FLT HAD BEEN CLRED TO DSND OUT OF 10000 FT TO 7000 FT ON A 230 DEG HDG BY LAX APCH CTL. AT ABOUT 8500 FT AND IN A 1200 FPM DSCNT IN A MODERATE RAIN SHOWER, THE GPWS SOUNDED THE 'WHOOP, WHOOP, PULL UP' WITH THE RED WARNING LIGHTS, THEN 'TERRAIN, TERRAIN, TOO LOW GEAR, TOO LOW FLAP.' THE DSCNT WAS STOPPED AND A SLIGHT CLB WAS INITIATED TO 8900 FT. THE WARNINGS STOPPED AND THE DSCNT WAS RESUMED WITH NO FURTHER WARNINGS. I SUSPECT THIS WAS CAUSED BY THE EFFECT OF THE RAIN SHOWER ON THE GPWS. NO OTHER CAUSES WERE APPARENT.

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.