An air carrier large transport sent a false TCASII warning both to another aircraft and ARTCC.

Attributes
ACN	245360
Time
Date	199306
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : lev
State Reference	LA
Altitude	msl bound lower : 33000 msl bound upper : 33000
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zjx tracon : phx
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Route In Use	enroute other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : private pilot : instrument pilot : flight engineer pilot : atp pilot : commercial
Experience	flight time last 90 days : 230 flight time total : 11000 flight time type : 7000
ASRS Report	245360
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : cfi pilot : flight engineer
Experience	flight time last 90 days : 250 flight time total : 10000 flight time type : 250
ASRS Report	245563
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa
Resolutory Action	flight crew : overcame equipment problem other other
Consequence	faa : reviewed incident with flight crew
Miss Distance	vertical : 2000
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

ZJX called to verify our altitude. We verified FL330. Their response was a company flight crossing overhead at FL350 had received an advisory on their TCASII. Likewise, center had received an alert on their scope of 33800 ft. We advised center we were level at 33000 ft. Upon landing, we phoned ZJX to speak with their supervisor on duty. He said they had reviewed their tapes and had found 1 sweep at 33000 ft followed by 1 sweep at 33500 ft, followed by 1 sweep at 33800 ft, followed by a sweep at 33000 ft -- all of this occurring within 10-12 seconds, which he knew was not possible. Hence, he had overridden the automatic filing/notification and had noted such to be an erroneous TCASII signal. Our altitude had remained constant at FL330 during all of this!

Original NASA ASRS Text

Title: AN ACR LGT SENT A FALSE TCASII WARNING BOTH TO ANOTHER ACFT AND ARTCC.

Narrative: ZJX CALLED TO VERIFY OUR ALT. WE VERIFIED FL330. THEIR RESPONSE WAS A COMPANY FLT XING OVERHEAD AT FL350 HAD RECEIVED AN ADVISORY ON THEIR TCASII. LIKEWISE, CTR HAD RECEIVED AN ALERT ON THEIR SCOPE OF 33800 FT. WE ADVISED CTR WE WERE LEVEL AT 33000 FT. UPON LNDG, WE PHONED ZJX TO SPEAK WITH THEIR SUPVR ON DUTY. HE SAID THEY HAD REVIEWED THEIR TAPES AND HAD FOUND 1 SWEEP AT 33000 FT FOLLOWED BY 1 SWEEP AT 33500 FT, FOLLOWED BY 1 SWEEP AT 33800 FT, FOLLOWED BY A SWEEP AT 33000 FT -- ALL OF THIS OCCURRING WITHIN 10-12 SECONDS, WHICH HE KNEW WAS NOT POSSIBLE. HENCE, HE HAD OVERRIDDEN THE AUTOMATIC FILING/NOTIFICATION AND HAD NOTED SUCH TO BE AN ERRONEOUS TCASII SIGNAL. OUR ALT HAD REMAINED CONSTANT AT FL330 DURING ALL OF THIS!

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.