A B737-300, in cruise at FL330, responded to a climb RA from TCASII.

Attributes
ACN	558343
Time
Date	200208
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : cle.airport
State Reference	OH
Altitude	msl bound lower : 33000 msl bound upper : 34500
Environment
Flight Conditions	IMC
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zob.artcc
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 230 flight time total : 7500 flight time type : 4000
ASRS Report	558343
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude other anomaly other
Independent Detector	aircraft equipment : tcas other flight crewa other flight crewb
Resolutory Action	flight crew : took evasive action other
Consequence	faa : reviewed incident with flight crew other
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

We were at FL330 when we received an instantaneous RA advising us to climb. I was suspicious that it was a false advisory since center had not advised us of any traffic, and normally an RA is precursed by the yellow symbol with 'traffic' aural warning. However, the traffic target displayed very close to us, so I commanded the first officer to follow the TCASII guidance. We climbed to FL345 and advised ATC. ATC responded that nobody else was near us. The traffic target on the TCASII matched our climb exactly and was showing our exact same position, so we determined that it was a false RA and stopped our climb. We returned to FL330 and advised ATC. Luckily, there was no actual FL350 traffic or else there may have been a real conflict. We had to turn the TCASII off to cancel the warning. The rest of the flight was normal.

Original NASA ASRS Text

Title: A B737-300, IN CRUISE AT FL330, RESPONDED TO A CLB RA FROM TCASII.

Narrative: WE WERE AT FL330 WHEN WE RECEIVED AN INSTANTANEOUS RA ADVISING US TO CLB. I WAS SUSPICIOUS THAT IT WAS A FALSE ADVISORY SINCE CTR HAD NOT ADVISED US OF ANY TFC, AND NORMALLY AN RA IS PRECURSED BY THE YELLOW SYMBOL WITH 'TFC' AURAL WARNING. HOWEVER, THE TFC TARGET DISPLAYED VERY CLOSE TO US, SO I COMMANDED THE FO TO FOLLOW THE TCASII GUIDANCE. WE CLBED TO FL345 AND ADVISED ATC. ATC RESPONDED THAT NOBODY ELSE WAS NEAR US. THE TFC TARGET ON THE TCASII MATCHED OUR CLB EXACTLY AND WAS SHOWING OUR EXACT SAME POS, SO WE DETERMINED THAT IT WAS A FALSE RA AND STOPPED OUR CLB. WE RETURNED TO FL330 AND ADVISED ATC. LUCKILY, THERE WAS NO ACTUAL FL350 TFC OR ELSE THERE MAY HAVE BEEN A REAL CONFLICT. WE HAD TO TURN THE TCASII OFF TO CANCEL THE WARNING. THE REST OF THE FLT WAS NORMAL.

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.