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

Attributes
ACN	190054
Time
Date	199109
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : dsm
State Reference	IA
Altitude	msl bound lower : 33000 msl bound upper : 33000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zmp tower : pdx
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
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
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 7
ASRS Report	190054
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 non adherence : clearance
Independent Detector	atc equipment other atc equipment : unspecified
Resolutory Action	none taken : detected after the fact
Consequence	faa : investigated
Miss Distance	horizontal : 22176 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Air carrier X and Y both on vectors, however air carrier X was vectored off course for traffic. I issued a 070 heading/J60. About 1 1/2 mins later was assigned heading of 065. A min or more later assigned a 060 heading. The ntap readout shows no change, if not a negative change in heading throughout period of time. I feel pilots assumed the later headings were course corrections for J60, but onboard navigation was reading on VOR. Air carrier X decided to continue on J60 as if my headings were course corrections for the airway. Enclosed ntap shows little to no change in direction. Headings are relative to time issued and lines through targets are drawn by me to depict the fact that little to negative change had occurred.

Original NASA ASRS Text

Title: ACR X HAD LTSS FROM ACR Y. SYS ERROR.

Narrative: ACR X AND Y BOTH ON VECTORS, HOWEVER ACR X WAS VECTORED OFF COURSE FOR TFC. I ISSUED A 070 HDG/J60. ABOUT 1 1/2 MINS LATER WAS ASSIGNED HDG OF 065. A MIN OR MORE LATER ASSIGNED A 060 HDG. THE NTAP READOUT SHOWS NO CHANGE, IF NOT A NEGATIVE CHANGE IN HDG THROUGHOUT PERIOD OF TIME. I FEEL PLTS ASSUMED THE LATER HDGS WERE COURSE CORRECTIONS FOR J60, BUT ONBOARD NAV WAS READING ON VOR. ACR X DECIDED TO CONTINUE ON J60 AS IF MY HDGS WERE COURSE CORRECTIONS FOR THE AIRWAY. ENCLOSED NTAP SHOWS LITTLE TO NO CHANGE IN DIRECTION. HDGS ARE RELATIVE TO TIME ISSUED AND LINES THROUGH TARGETS ARE DRAWN BY ME TO DEPICT THE FACT THAT LITTLE TO NEGATIVE CHANGE HAD OCCURRED.

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.