Aircraft X had less than standard separation from aircraft Y. System error.

Attributes
ACN	123357
Time
Date	198909
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ocs
State Reference	WY
Altitude	msl bound lower : 31000 msl bound upper : 33000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zlc artcc : zdv
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : flight data
Qualification	controller : non radar
Experience	controller radar : 1
ASRS Report	123357
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	other other : unspecified atc
Resolutory Action	none taken : detected after the fact
Consequence	faa : investigated
Miss Distance	horizontal : 27000 vertical : 1500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Aircraft X shipped to ZLC from ZDV, level FL310 requested FL350. ZDC gave control on aircraft X reference aircraft Y, eastbound at FL330 and an aircraft wbound at FL350. Assistant controller misunderstood--did not hear aircraft Y at FL330. Aircraft X at FL301 was given clearance to FL330. This occurred during a period of heavy traffic, approximately 20 radar contacts. When control on aircraft X was passed, 2 headings and a radar handoff were passed at the same time. An FSS was also calling on another line. The C/a never went off in ZLC. It is understood that it did go off in ZDV system. I believe the problem was ultimately caused by not listening properly to the information passed by ZDV and then not properly passed to r-ctlr.

Original NASA ASRS Text

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

Narrative: ACFT X SHIPPED TO ZLC FROM ZDV, LEVEL FL310 REQUESTED FL350. ZDC GAVE CTL ON ACFT X REF ACFT Y, EBND AT FL330 AND AN ACFT WBOUND AT FL350. ASSISTANT CTLR MISUNDERSTOOD--DID NOT HEAR ACFT Y AT FL330. ACFT X AT FL301 WAS GIVEN CLRNC TO FL330. THIS OCCURRED DURING A PERIOD OF HEAVY TFC, APPROX 20 RADAR CONTACTS. WHEN CTL ON ACFT X WAS PASSED, 2 HDGS AND A RADAR HDOF WERE PASSED AT THE SAME TIME. AN FSS WAS ALSO CALLING ON ANOTHER LINE. THE C/A NEVER WENT OFF IN ZLC. IT IS UNDERSTOOD THAT IT DID GO OFF IN ZDV SYS. I BELIEVE THE PROB WAS ULTIMATELY CAUSED BY NOT LISTENING PROPERLY TO THE INFO PASSED BY ZDV AND THEN NOT PROPERLY PASSED TO R-CTLR.

Data retrieved from NASA's ASRS site as of August 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.