ARTCC controller descended an medium large transport, then saw potential conflict, and turned both aircraft prior to separation loss.

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Attributes
ACN	193784
Time
Date	199111
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ave
State Reference	CA
Altitude	msl bound lower : 25000 msl bound upper : 26000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude descent other
Route In Use	enroute : on vectors enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	193784
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe
Independent Detector	atc equipment other atc equipment : unspecified aircraft equipment other aircraft equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Miss Distance	horizontal : 30000 vertical : 650
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other

Narrative:

We had been given clearance from FL260 to FL240 while proceeding direct to avenal. At approximately FL250 ZLA gave us a right 90 degree turn and a climb back to FL260 which we immediately executed. Upon reaching FL260 on heading for approximately 1-2 mins, we were reclred direct to sns and to descend to FL240. When I asked controller if a conflict occurred he replied no, but it was close to having one. I believe the controller may have made an error, but caught it in time to prevent a major problem. Supplemental information from acn 193785: we were at FL250. TCASII gave TA, ATC gave us a 60 degree turn to the right and conflicting aircraft a turn to the right. TCASII gave RA to climb, with visual contact we started a climb. ATC at the same time told us to descend and the conflicting aircraft to climb. We started a descent to FL240 and TCASII gave clear of conflict. ATC stated everything worked out ok.

Original NASA ASRS Text

Title: ARTCC CTLR DSNDED AN MLG, THEN SAW POTENTIAL CONFLICT, AND TURNED BOTH ACFT PRIOR TO SEPARATION LOSS.

Narrative: WE HAD BEEN GIVEN CLRNC FROM FL260 TO FL240 WHILE PROCEEDING DIRECT TO AVENAL. AT APPROX FL250 ZLA GAVE US A R 90 DEG TURN AND A CLB BACK TO FL260 WHICH WE IMMEDIATELY EXECUTED. UPON REACHING FL260 ON HDG FOR APPROX 1-2 MINS, WE WERE RECLRED DIRECT TO SNS AND TO DSND TO FL240. WHEN I ASKED CTLR IF A CONFLICT OCCURRED HE REPLIED NO, BUT IT WAS CLOSE TO HAVING ONE. I BELIEVE THE CTLR MAY HAVE MADE AN ERROR, BUT CAUGHT IT IN TIME TO PREVENT A MAJOR PROBLEM. SUPPLEMENTAL INFO FROM ACN 193785: WE WERE AT FL250. TCASII GAVE TA, ATC GAVE US A 60 DEG TURN TO THE R AND CONFLICTING ACFT A TURN TO THE R. TCASII GAVE RA TO CLB, WITH VISUAL CONTACT WE STARTED A CLB. ATC AT THE SAME TIME TOLD US TO DSND AND THE CONFLICTING ACFT TO CLB. WE STARTED A DSCNT TO FL240 AND TCASII GAVE CLR OF CONFLICT. ATC STATED EVERYTHING WORKED OUT OK.

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.