Air carrier X holding at same altitude had less than standard separation from air carrier Y. System ...

Attributes
ACN	243947
Time
Date	199306
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : olm
State Reference	WA
Altitude	msl bound lower : 10000 msl bound upper : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zse tower : sea
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Flight Phase	other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Flight Phase	other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 1
ASRS Report	243947
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	faa : investigated
Miss Distance	horizontal : 27600 vertical : 300
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

I cleared an air carrier X into holding for metering and then asked him to meet a metering time inbound over the fix he was holding at but did not actually clear the aircraft inbound on the arrival. After transferring communications with air carrier X to seattle approach, the aircraft turned around (in holding) head-on with another air carrier Y at the same altitude. I turned air carrier Y (I was still talking to) immediately away and climbed him, however, separation was lost at 4.6 mi. The aircraft I was in communications with had the first aircraft in sight.

Original NASA ASRS Text

Title: ACR X HOLDING AT SAME ALT HAD LTSS FROM ACR Y. SYS ERROR.

Narrative: I CLRED AN ACR X INTO HOLDING FOR METERING AND THEN ASKED HIM TO MEET A METERING TIME INBOUND OVER THE FIX HE WAS HOLDING AT BUT DID NOT ACTUALLY CLR THE ACFT INBOUND ON THE ARR. AFTER TRANSFERRING COMS WITH ACR X TO SEATTLE APCH, THE ACFT TURNED AROUND (IN HOLDING) HEAD-ON WITH ANOTHER ACR Y AT THE SAME ALT. I TURNED ACR Y (I WAS STILL TALKING TO) IMMEDIATELY AWAY AND CLBED HIM, HOWEVER, SEPARATION WAS LOST AT 4.6 MI. THE ACFT I WAS IN COMS WITH HAD THE FIRST ACFT IN SIGHT.

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 holding at same altitude had less than standard separation from air carrier Y. System error.