Flight crew responded to TCASII RA during descent.

Attributes
ACN	314522
Time
Date	199508
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : bal
State Reference	MD
Altitude	msl bound lower : 12500 msl bound upper : 13000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : bwi
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	enroute airway : bwi enroute other
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : unknown
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 210 flight time total : 18000 flight time type : 14000
ASRS Report	314522
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : crossing restriction not met altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action flight crew : returned to intended course or assigned course other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

We were cleared to cross 15 mi north of balance at 12000 ft. At approximately 18 mi north of balance descending through 12500 ft we got a TA on the TCASII followed by a command to climb at approximately 1000 FPM, which we did. At approximately 13000 ft we received a clear of conflict and descended back to 12000 ft. The controller advised that he had not seen the traffic prior to our climb but did have him following our climb.

Original NASA ASRS Text

Title: FLC RESPONDED TO TCASII RA DURING DSCNT.

Narrative: WE WERE CLRED TO CROSS 15 MI N OF BAL AT 12000 FT. AT APPROX 18 MI N OF BAL DSNDING THROUGH 12500 FT WE GOT A TA ON THE TCASII FOLLOWED BY A COMMAND TO CLB AT APPROX 1000 FPM, WHICH WE DID. AT APPROX 13000 FT WE RECEIVED A CLR OF CONFLICT AND DSNDED BACK TO 12000 FT. THE CTLR ADVISED THAT HE HAD NOT SEEN THE TFC PRIOR TO OUR CLB BUT DID HAVE HIM FOLLOWING OUR 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.