TCASII gave RA while in overcast and the flight crew deviated 300' from altitude.

Attributes
ACN	177069
Time
Date	199104
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : lax
State Reference	CA
Altitude	msl bound lower : 2500 msl bound upper : 2800
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : lax
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : commercial pilot : flight engineer pilot : instrument
Experience	flight time last 90 days : 200 flight time total : 3000 flight time type : 700
ASRS Report	177069
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial pilot : flight engineer pilot : instrument
Experience	flight time last 90 days : 310 flight time total : 14250 flight time type : 8000
ASRS Report	176245
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : took evasive action
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Level at 2500 ft MSL, downwind for ILS 24R, received TA alert on TCAS. Intruder was indicated to be at -100 ft relative altitude, 10 O'clock, less than 1 mi. A few moments later, received RA instructing us to climb. Associated symbology was present (red DOT for intruder, red arc on TA/vsi). Complied with RA, after gaining 300 ft, RA disappeard and immediate correction back to assigned altitude was made. Approach control notified.

Original NASA ASRS Text

Title: TCASII GAVE RA WHILE IN OVERCAST AND THE FLT CREW DEVIATED 300' FROM ALT.

Narrative: LEVEL AT 2500 FT MSL, DOWNWIND FOR ILS 24R, RECEIVED TA ALERT ON TCAS. INTRUDER WAS INDICATED TO BE AT -100 FT RELATIVE ALT, 10 O'CLOCK, LESS THAN 1 MI. A FEW MOMENTS LATER, RECEIVED RA INSTRUCTING US TO CLB. ASSOCIATED SYMBOLOGY WAS PRESENT (RED DOT FOR INTRUDER, RED ARC ON TA/VSI). COMPLIED WITH RA, AFTER GAINING 300 FT, RA DISAPPEARD AND IMMEDIATE CORRECTION BACK TO ASSIGNED ALT WAS MADE. APCH CTL NOTIFIED.

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.