Widebody transport flight crew receives TCASII RA on descent. Responds.

Attributes
ACN	226538
Time
Date	199211
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : lgw
State Reference	FO
Altitude	msl bound lower : 11500 msl bound upper : 12000
Environment
Flight Conditions	IMC
Light	Dawn
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 3 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent other
Route In Use	enroute airway : lgw
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 80 flight time total : 20000
ASRS Report	226538
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : took evasive action none taken : anomaly accepted
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation other

Narrative:

I was flying in descent out of FL130 for FL120. Flight guidance and autoplt set and armed for FL120. Heard RA TCASII command to descend, glanced at TCASII screen saw red square at 1230 O'clock position, went to vertical speed indicator and saw green band commanding 2000 ft down. Adjusted our rate of descent until RA cleared then returned to FL120. Altitude deviation approximately 500 ft below FL120. Very busy segment of flight approaching selsi intersection on lgw willo 1A arrival. Notified ATC by telephone of RA after landing.

Original NASA ASRS Text

Title: WDB FLC RECEIVES TCASII RA ON DSCNT. RESPONDS.

Narrative: I WAS FLYING IN DSCNT OUT OF FL130 FOR FL120. FLT GUIDANCE AND AUTOPLT SET AND ARMED FOR FL120. HEARD RA TCASII COMMAND TO DSND, GLANCED AT TCASII SCREEN SAW RED SQUARE AT 1230 O'CLOCK POS, WENT TO VERT SPD INDICATOR AND SAW GREEN BAND COMMANDING 2000 FT DOWN. ADJUSTED OUR RATE OF DSCNT UNTIL RA CLRED THEN RETURNED TO FL120. ALTDEV APPROX 500 FT BELOW FL120. VERY BUSY SEGMENT OF FLT APCHING SELSI INTXN ON LGW WILLO 1A ARR. NOTIFIED ATC BY TELEPHONE OF RA AFTER LNDG.

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.