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

Attributes
ACN	136802
Time
Date	199002
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : pae
State Reference	WA
Altitude	msl bound lower : 33300 msl bound upper : 33300
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zse
Operator	other
Make Model Name	Fighter
Flight Phase	descent other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
ASRS Report	136802
Person 2
Affiliation	government : military
Function	flight crew : single pilot
Qualification	pilot : military
Events
Anomaly	altitude deviation : overshoot conflict : airborne less severe non adherence : required legal separation non adherence : published procedure
Independent Detector	atc equipment other atc equipment : unspecified
Resolutory Action	controller : issued new clearance other
Consequence	faa : investigated
Miss Distance	horizontal : 27540 vertical : 1000
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Fgt X working in the darrington airspace, descending from fl390b410 to fl290b310 on a northeasterly course. Approximately 30 mi south of his position was air carrier Y, south of the pae VOR, inbound to yvr on the accord 2 arrival. Air carrier Y was at 350 with discretion to 190. At this time I did not believe that a traffic conflict was imminent. My attention was diverted to an mlt departing whidbey island, requiring a pointout to sea approach and a turn on course. During this time, fgt X reversed course (military aircraft in the darrington area have course/heading at pilot's discretion unless assigned) and was headed toward air carrier Y conflict alert activated and I saw that immediate action was required to resolve what could have been a disastrous situation. Fgt X was given an altitude stop of FL340 and an immediate left turn to 010, and air carrier Y was told to expedite thru FL310. Fgt X was in such a descent profile that he was unable to stop at FL340 and passed to FL333. At this point separation was lost. 4.59 NM and 1000' vertical. Separation was reestablished on the next radar update and there were no adverse effects to either flight.

Original NASA ASRS Text

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

Narrative: FGT X WORKING IN THE DARRINGTON AIRSPACE, DESCENDING FROM FL390B410 TO FL290B310 ON A NORTHEASTERLY COURSE. APPROX 30 MI S OF HIS POSITION WAS ACR Y, S OF THE PAE VOR, INBND TO YVR ON THE ACCORD 2 ARR. ACR Y WAS AT 350 WITH DISCRETION TO 190. AT THIS TIME I DID NOT BELIEVE THAT A TFC CONFLICT WAS IMMINENT. MY ATTN WAS DIVERTED TO AN MLT DEPARTING WHIDBEY ISLAND, REQUIRING A POINTOUT TO SEA APCH AND A TURN ON COURSE. DURING THIS TIME, FGT X REVERSED COURSE (MIL ACFT IN THE DARRINGTON AREA HAVE COURSE/HDG AT PLT'S DISCRETION UNLESS ASSIGNED) AND WAS HEADED TOWARD ACR Y CONFLICT ALERT ACTIVATED AND I SAW THAT IMMEDIATE ACTION WAS REQUIRED TO RESOLVE WHAT COULD HAVE BEEN A DISASTROUS SITUATION. FGT X WAS GIVEN AN ALT STOP OF FL340 AND AN IMMEDIATE LEFT TURN TO 010, AND ACR Y WAS TOLD TO EXPEDITE THRU FL310. FGT X WAS IN SUCH A DSCNT PROFILE THAT HE WAS UNABLE TO STOP AT FL340 AND PASSED TO FL333. AT THIS POINT SEPARATION WAS LOST. 4.59 NM AND 1000' VERTICAL. SEPARATION WAS REESTABLISHED ON THE NEXT RADAR UPDATE AND THERE WERE NO ADVERSE EFFECTS TO EITHER FLT.

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.