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

Attributes
ACN	165786
Time
Date	199012
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : dls
State Reference	OR
Altitude	msl bound lower : 18000 msl bound upper : 18000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zse
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	climbout : intermediate altitude 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	cruise other descent other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : non radar
Qualification	controller : developmental
Experience	controller military : 3
ASRS Report	165786
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation non adherence : published procedure
Independent Detector	atc equipment other atc equipment : unspecified
Resolutory Action	none taken : unable
Consequence	faa : investigated
Miss Distance	horizontal : 9000 vertical : 800
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Air carrier X climbing eastbound to 17000'. Air carrier Y inbound landing pdx issue pilots discretion to FL180. I did not realize FL180 was unusable. No contributing factors. No time for corrective action. Discovered by conflict alert some factors affecting quality, sectors combined up. Unusually busy due to winter storm movement within past 3 hours.

Original NASA ASRS Text

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

Narrative: ACR X CLBING EBND TO 17000'. ACR Y INBND LNDG PDX ISSUE PLTS DISCRETION TO FL180. I DID NOT REALIZE FL180 WAS UNUSABLE. NO CONTRIBUTING FACTORS. NO TIME FOR CORRECTIVE ACTION. DISCOVERED BY CONFLICT ALERT SOME FACTORS AFFECTING QUALITY, SECTORS COMBINED UP. UNUSUALLY BUSY DUE TO WINTER STORM MOVEMENT WITHIN PAST 3 HRS.

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.