B737-800 flight crew initiate TCASII evasive maneuver due to climbing B737 from behind.

Attributes
ACN	516942
Time
Date	200107
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : hsv.airport
State Reference	AL
Altitude	msl single value : 29000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl.artcc
Operator	common carrier : air carrier
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : ztl.artcc
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : enroute altitude change
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : multi engine pilot : instrument pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 150 flight time total : 8785 flight time type : 385
ASRS Report	516942
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	other flight crewa
Resolutory Action	controller : issued advisory flight crew : overrode automation flight crew : took precautionary avoidance action flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 15000 vertical : 1000
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance Airspace Structure
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

While in cruise flight, initially received a TA on a target climbing at our 10-11 O'clock position. The first officer was at the controls. I tried to acquire the target visually. While I was looking, the TA changed to an 'climb' RA. I did not have the target in sight and also announced 'climb' and reported the RA and our climb to ATC. ZTL reported that the closest aircraft was an air carrier Y 15 NM away. The target was continuing to close our position, both horizontally and vertically. I commanded 'increase' climb to the first officer. I finally acquired the target passing behind at about our 4 O'clock position. According to TCASII, closest approach was at 2 NM and at 1000 ft due to our 800-900 ft climb.

Original NASA ASRS Text

Title: B737-800 FLC INITIATE TCASII EVASIVE MANEUVER DUE TO CLBING B737 FROM BEHIND.

Narrative: WHILE IN CRUISE FLT, INITIALLY RECEIVED A TA ON A TARGET CLBING AT OUR 10-11 O'CLOCK POS. THE FO WAS AT THE CTLS. I TRIED TO ACQUIRE THE TARGET VISUALLY. WHILE I WAS LOOKING, THE TA CHANGED TO AN 'CLB' RA. I DID NOT HAVE THE TARGET IN SIGHT AND ALSO ANNOUNCED 'CLB' AND RPTED THE RA AND OUR CLB TO ATC. ZTL RPTED THAT THE CLOSEST ACFT WAS AN ACR Y 15 NM AWAY. THE TARGET WAS CONTINUING TO CLOSE OUR POS, BOTH HORIZLY AND VERTLY. I COMMANDED 'INCREASE' CLB TO THE FO. I FINALLY ACQUIRED THE TARGET PASSING BEHIND AT ABOUT OUR 4 O'CLOCK POS. ACCORDING TO TCASII, CLOSEST APCH WAS AT 2 NM AND AT 1000 FT DUE TO OUR 800-900 FT CLB.

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.