An air carrier widebody transport crew climbed in response to an apparently false warning from TCASI...

Attributes
ACN	260265
Time
Date	199312
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : sya
State Reference	AK
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute : pacific enroute : other oceanic
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 225 flight time total : 8000 flight time type : 900
ASRS Report	260265
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : took evasive action flight crew : returned to intended course or assigned course flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation other

Narrative:

Crew received TCASII warning (climb command). Crew initiated evasive command until discerning warning as being false. TCASII showed only traffic in area (besides displayed TA ghost) was another plane 10 mi behind. We advised him on 128.95 MHZ of our climb and he responded and had us in sight. Selected '7700' on transponder while climbing and returning to cleared altitude. Anc ATC was out of range and we were unable to contact honolulu HF commercial radio until well after action was taken. TCASII had previous history of some maintenance 'status' messages. Suggestions were made to company for maintenance to render TCASII inoperative by pulling and collaring TCASII circuit breaker and to instruct crew to operate in transponder only mode.

Original NASA ASRS Text

Title: AN ACR WDB CREW CLBED IN RESPONSE TO AN APPARENTLY FALSE WARNING FROM TCASII.

Narrative: CREW RECEIVED TCASII WARNING (CLB COMMAND). CREW INITIATED EVASIVE COMMAND UNTIL DISCERNING WARNING AS BEING FALSE. TCASII SHOWED ONLY TFC IN AREA (BESIDES DISPLAYED TA GHOST) WAS ANOTHER PLANE 10 MI BEHIND. WE ADVISED HIM ON 128.95 MHZ OF OUR CLB AND HE RESPONDED AND HAD US IN SIGHT. SELECTED '7700' ON XPONDER WHILE CLBING AND RETURNING TO CLRED ALT. ANC ATC WAS OUT OF RANGE AND WE WERE UNABLE TO CONTACT HONOLULU HF COMMERCIAL RADIO UNTIL WELL AFTER ACTION WAS TAKEN. TCASII HAD PREVIOUS HISTORY OF SOME MAINT 'STATUS' MESSAGES. SUGGESTIONS WERE MADE TO COMPANY FOR MAINT TO RENDER TCASII INOP BY PULLING AND COLLARING TCASII CIRCUIT BREAKER AND TO INSTRUCT CREW TO OPERATE IN XPONDER ONLY MODE.

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.

An air carrier widebody transport crew climbed in response to an apparently false warning from TCASII.