Air carrier X had less than standard separation from air carrier Y. System error.

Attributes
ACN	148925
Time
Date	199006
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : pdx
State Reference	OR
Altitude	msl bound lower : 31000 msl bound upper : 32200
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zse
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	descent other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : non radar
Qualification	controller : radar
Experience	controller radar : 6
ASRS Report	148925
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	conflict : airborne less severe non adherence : clearance non adherence : published procedure non adherence : required legal separation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Miss Distance	horizontal : 27000 vertical : 1200
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Pilot Deviation Operational Error

Narrative:

I was working d-side and observed radar controller issue a clearance that was in conflict with another aircraft. Air carrier X was level FL310 northbound. The r-side issued a clearance to air carrier Y at FL350 to descend to FL240. These aircraft were approximately 6 NM apart and appeared to be decreasing. I told r-side to stop air carrier Y at FL330! He did. I felt the situation was resolved and began taking coordination. I looked again and saw air carrier Y descending out of FL328 with about 5 NM (minimum sep) and decreasing. I told r-side again to climb him back to FL330!

Original NASA ASRS Text

Title: ACR X HAD LESS THAN STANDARD SEPARATION FROM ACR Y. SYSTEM ERROR.

Narrative: I WAS WORKING D-SIDE AND OBSERVED RADAR CTLR ISSUE A CLRNC THAT WAS IN CONFLICT WITH ANOTHER ACFT. ACR X WAS LEVEL FL310 NBND. THE R-SIDE ISSUED A CLRNC TO ACR Y AT FL350 TO DSND TO FL240. THESE ACFT WERE APPROX 6 NM APART AND APPEARED TO BE DECREASING. I TOLD R-SIDE TO STOP ACR Y AT FL330! HE DID. I FELT THE SITUATION WAS RESOLVED AND BEGAN TAKING COORD. I LOOKED AGAIN AND SAW ACR Y DSNDING OUT OF FL328 WITH ABOUT 5 NM (MINIMUM SEP) AND DECREASING. I TOLD R-SIDE AGAIN TO CLB HIM BACK TO FL330!

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.