An large transport crew climbed in response to a TCASII alert while in the approach pattern at dfw.

Attributes
ACN	218965
Time
Date	199208
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : dfw
State Reference	TX
Altitude	msl bound lower : 3000 msl bound upper : 3800
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dfw tower : tus
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent : approach
Route In Use	arrival other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 180 flight time total : 4800
ASRS Report	218965
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 178 flight time total : 19440 flight time type : 142
ASRS Report	218974
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 : returned to intended course or assigned course flight crew : took evasive action
Consequence	Other
Miss Distance	vertical : 800
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation other

Narrative:

At approximately 8 mi south of chaar intersection at 3000 ft MSL assigned on ILS 36L at dfw, TCASII alerted intrusion by another aircraft. TCASII indicated intruder to be 1-2 mi northeast, 700 ft below us and climbing. At 500 ft below and climbing, we received a TCASII resolution command to climb. Neither the captain nor I had visual contact with aircraft. Captain initiated a climb to clear traffic and leveled off at 3800 ft MSL. Still no visual on traffic. After clear of traffic, we descended back to our assigned altitude of 3000 ft MSL. Supplemental information from acn 218974. Visibility at airport was reported as 6 mi in haze, but more like 2 or 3 on approach.

Original NASA ASRS Text

Title: AN LGT CREW CLBED IN RESPONSE TO A TCASII ALERT WHILE IN THE APCH PATTERN AT DFW.

Narrative: AT APPROX 8 MI S OF CHAAR INTXN AT 3000 FT MSL ASSIGNED ON ILS 36L AT DFW, TCASII ALERTED INTRUSION BY ANOTHER ACFT. TCASII INDICATED INTRUDER TO BE 1-2 MI NE, 700 FT BELOW US AND CLBING. AT 500 FT BELOW AND CLBING, WE RECEIVED A TCASII RESOLUTION COMMAND TO CLB. NEITHER THE CAPT NOR I HAD VISUAL CONTACT WITH ACFT. CAPT INITIATED A CLB TO CLR TFC AND LEVELED OFF AT 3800 FT MSL. STILL NO VISUAL ON TFC. AFTER CLR OF TFC, WE DSNDED BACK TO OUR ASSIGNED ALT OF 3000 FT MSL. SUPPLEMENTAL INFO FROM ACN 218974. VISIBILITY AT ARPT WAS RPTED AS 6 MI IN HAZE, BUT MORE LIKE 2 OR 3 ON 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.