Air carrier X TCASII traffic had less than standard separation from aircraft Y. Evasive action turn....

Attributes
ACN	230481
Time
Date	199301
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : flo
State Reference	FO
Altitude	msl bound lower : 29000 msl bound upper : 29000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : lppo tower : pdx
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute : other oceanic enroute : atlantic
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Route In Use	enroute : atlantic enroute : other oceanic
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 13000
ASRS Report	230481
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : clearance non adherence : published procedure non adherence : required legal separation
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 18000
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Air carrier X oceanic clearance out of azores at FL290. TCASII displays other aircraft Y at same altitude going to same fix. VFR maneuver to pass behind other aircraft. Aircraft (other) subsequently climbs. In a non-radar environment, we were within 3 mi of each other at same altitude.

Original NASA ASRS Text

Title: ACR X TCASII TFC HAD LTSS FROM ACFT Y. EVASIVE ACTION TURN. SYS ERROR.

Narrative: ACR X OCEANIC CLRNC OUT OF AZORES AT FL290. TCASII DISPLAYS OTHER ACFT Y AT SAME ALT GOING TO SAME FIX. VFR MANEUVER TO PASS BEHIND OTHER ACFT. ACFT (OTHER) SUBSEQUENTLY CLBS. IN A NON-RADAR ENVIRONMENT, WE WERE WITHIN 3 MI OF EACH OTHER AT SAME ALT.

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.

Air carrier X TCASII traffic had less than standard separation from aircraft Y. Evasive action turn. System error.