An MD80 flight crew receives a TCASII RA.

Attributes
ACN	523480
Time
Date	200109
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : ccr.airport
State Reference	CA
Altitude	msl single value : 13000
Environment
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Flight Phase	climbout : intermediate altitude
Route In Use	departure : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	climbout : intermediate altitude
Route In Use	departure : vfr
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
Experience	flight time last 90 days : 240 flight time total : 11000 flight time type : 2800
ASRS Report	523480
Events
Anomaly	conflict : nmac
Resolutory Action	flight crew : took precautionary avoidance action
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	Ambiguous

Narrative:

Climbing through approximately 13000 ft MSL we received a traffic alert (TCASII) for traffic at approximately our 11 O'clock position about 5 mi and 800 ft below us. The traffic was slightly out climbing us and converging. We then received an RA to reduce our climb rate and then another RA to descend. After we began our descent, the TCASII advised us of crossing traffic. I noticed on the TCASII however that it appeared that the conflicting traffic stopped their climb and also began a descent. Our TCASII continued to advise a descent. The traffic was converging on our position and was within 100 ft of our altitude. I increased the rate of descent which reached at least 4000 ft a min at one point. When we were advised clear of conflict we leveled at 11000 ft MSL and then resumed our climb. We advised ATC of our TCASII maneuver. They were obviously unaware of any traffic nearby (or at least didn't acknowledge it to us). A very rough estimate of the closest proximity of the traffic was 1 mi horizontally and 0 ft vertically. We never did acquire a visual on the traffic to ascertain type, direction of travel, etc.

Original NASA ASRS Text

Title: AN MD80 FLT CREW RECEIVES A TCASII RA.

Narrative: CLBING THROUGH APPROX 13000 FT MSL WE RECEIVED A TFC ALERT (TCASII) FOR TFC AT APPROX OUR 11 O'CLOCK POS ABOUT 5 MI AND 800 FT BELOW US. THE TFC WAS SLIGHTLY OUT CLBING US AND CONVERGING. WE THEN RECEIVED AN RA TO REDUCE OUR CLB RATE AND THEN ANOTHER RA TO DSND. AFTER WE BEGAN OUR DSCNT, THE TCASII ADVISED US OF XING TFC. I NOTICED ON THE TCASII HOWEVER THAT IT APPEARED THAT THE CONFLICTING TFC STOPPED THEIR CLB AND ALSO BEGAN A DSCNT. OUR TCASII CONTINUED TO ADVISE A DSCNT. THE TFC WAS CONVERGING ON OUR POS AND WAS WITHIN 100 FT OF OUR ALT. I INCREASED THE RATE OF DSCNT WHICH REACHED AT LEAST 4000 FT A MIN AT ONE POINT. WHEN WE WERE ADVISED CLR OF CONFLICT WE LEVELED AT 11000 FT MSL AND THEN RESUMED OUR CLB. WE ADVISED ATC OF OUR TCASII MANEUVER. THEY WERE OBVIOUSLY UNAWARE OF ANY TFC NEARBY (OR AT LEAST DIDN'T ACKNOWLEDGE IT TO US). A VERY ROUGH ESTIMATE OF THE CLOSEST PROX OF THE TFC WAS 1 MI HORIZLY AND 0 FT VERTLY. WE NEVER DID ACQUIRE A VISUAL ON THE TFC TO ASCERTAIN TYPE, DIRECTION OF TRAVEL, ETC.

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.