An air carrier flight crew received what they believed, was a false TCASII alert.

Attributes
ACN	302405
Time
Date	199504
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : lkv
State Reference	OR
Altitude	msl bound lower : 32500 msl bound upper : 33000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zse tower : pit
Operator	common carrier : air carrier
Make Model Name	B737-400
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 7000 flight time type : 1500
ASRS Report	302405
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : overcame equipment problem other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

During cruise at FL330 (N4317.8 W121 31.7) we received a TCASII 'traffic' alert at our 12 O'clock position (aircraft altitude 00), followed shortly by an RA to descend. We followed the RA and descended to 32500 ft. Within 30 seconds we returned to FL330. We advised ATC and they responded 'negative traffic.' within 3 mins the RA occurred again (no deviation) and we suspected a faulty TCASII.

Original NASA ASRS Text

Title: AN ACR FLC RECEIVED WHAT THEY BELIEVED, WAS A FALSE TCASII ALERT.

Narrative: DURING CRUISE AT FL330 (N4317.8 W121 31.7) WE RECEIVED A TCASII 'TFC' ALERT AT OUR 12 O'CLOCK POS (ACFT ALT 00), FOLLOWED SHORTLY BY AN RA TO DSND. WE FOLLOWED THE RA AND DSNDED TO 32500 FT. WITHIN 30 SECONDS WE RETURNED TO FL330. WE ADVISED ATC AND THEY RESPONDED 'NEGATIVE TFC.' WITHIN 3 MINS THE RA OCCURRED AGAIN (NO DEV) AND WE SUSPECTED A FAULTY TCASII.

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.