Flight crew of an medium large transport stopped climb and descended in response to a TCASII RA.

Attributes
ACN	374180
Time
Date	199707
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ave
State Reference	CA
Altitude	msl bound lower : 29000 msl bound upper : 29000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zoa tracon : ric
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude cruise other
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	other other : other pilot : instrument pilot : flight engineer pilot : atp pilot : commercial
Experience	flight time last 90 days : 240 flight time total : 10000 flight time type : 3000
ASRS Report	374180
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa
Resolutory Action	controller : issued new clearance flight crew : took evasive action other
Consequence	Other
Miss Distance	horizontal : 2000 vertical : 1100
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

In level cruise at FL290, ZOA asked for our heading. Copilot answered 114 degrees. ZOA said 'turn right 15 degrees and climb to FL330 for traffic.' copilot read back clearance and we began to comply. As we climbed through FL297, I noticed TCASII display of traffic at 12 O'clock at FL310. I asked copilot to confirm our clearance, but ZOA was busy reissuing our clearance to another flight with call sign very close to ours. At FL298 we got a TCASII advisory, so I disconnected autoplt and leveled off. At about FL299, TCASII issued a descend TA. About this time, ZOA cleared us to maintain present altitude and turn left 070 degrees. I complied with the turn and followed the TCASII descent advisory until it gave a 'clear of conflict' about FL297. I believe the major contributing factor to this incident was the similar call signs of the 2 flts. I think that ZOA gave us the clearance for the turn and climb, thinking he was giving it to the other flight. Please note that the copilot used our full call sign in all xmissions and both of us heard our call sign in ZOA's xmissions.

Original NASA ASRS Text

Title: FLC OF AN MLG STOPPED CLB AND DSNDED IN RESPONSE TO A TCASII RA.

Narrative: IN LEVEL CRUISE AT FL290, ZOA ASKED FOR OUR HDG. COPLT ANSWERED 114 DEGS. ZOA SAID 'TURN R 15 DEGS AND CLB TO FL330 FOR TFC.' COPLT READ BACK CLRNC AND WE BEGAN TO COMPLY. AS WE CLBED THROUGH FL297, I NOTICED TCASII DISPLAY OF TFC AT 12 O'CLOCK AT FL310. I ASKED COPLT TO CONFIRM OUR CLRNC, BUT ZOA WAS BUSY REISSUING OUR CLRNC TO ANOTHER FLT WITH CALL SIGN VERY CLOSE TO OURS. AT FL298 WE GOT A TCASII ADVISORY, SO I DISCONNECTED AUTOPLT AND LEVELED OFF. AT ABOUT FL299, TCASII ISSUED A DSND TA. ABOUT THIS TIME, ZOA CLRED US TO MAINTAIN PRESENT ALT AND TURN L 070 DEGS. I COMPLIED WITH THE TURN AND FOLLOWED THE TCASII DSCNT ADVISORY UNTIL IT GAVE A 'CLR OF CONFLICT' ABOUT FL297. I BELIEVE THE MAJOR CONTRIBUTING FACTOR TO THIS INCIDENT WAS THE SIMILAR CALL SIGNS OF THE 2 FLTS. I THINK THAT ZOA GAVE US THE CLRNC FOR THE TURN AND CLB, THINKING HE WAS GIVING IT TO THE OTHER FLT. PLEASE NOTE THAT THE COPLT USED OUR FULL CALL SIGN IN ALL XMISSIONS AND BOTH OF US HEARD OUR CALL SIGN IN ZOA'S XMISSIONS.

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.