Less than standard separation between 2 air carrier. Operational error.

Attributes
ACN	97564
Time
Date	198811
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : las
State Reference	NV
Altitude	msl bound lower : 21000 msl bound upper : 21000
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zla
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other descent other
Route In Use	enroute : on vectors enroute airway : zla
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : intermediate altitude cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 10000 flight time type : 6500
ASRS Report	97564
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 13000 flight time type : 350
ASRS Report	97633
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	other other : unspecified atc
Resolutory Action	controller : issued new clearance none taken : insufficient time
Consequence	faa : investigated
Miss Distance	horizontal : 15000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Our flight, air carrier X, was descending from altitude while flying a direct course to the boulder city VOR for landing in las. The first officer was flying and I was on the radio ZLA gave us a 10 degree course change to the left for traffic as we were passing approximately 26000'. A few mins later we were given another 15 degree left vector for company traffic that was climbing out of las. The controller called the position of our traffic and I could see the other medium large transport. It appeared to be about 3 mi away, and looked like it would pass well to our right. At about that time, as we were passing 21500', the controller suddenly told us to level at FL220 and our company flight to stop his climb at FL210. We stopped our descent at about FL210 as our company passed abeam 2-3 mi away. When we were told to stop at FL220 I told the controller we were already at 21500'. After we passed I asked the controller if he wanted us to continue our descent and he said yes. I saw the other aircraft for some time before and as we passed, and never felt there was any conflict. The controller sounded pretty tense about it when he gave us our late level off call. I'm not sure what the problem was. Evidently the controller didn't see until too late that on our vectors, we would not keep minimum sep although it looked to me as though we had more than enough sep the whole time.

Original NASA ASRS Text

Title: LESS THAN STANDARD SEPARATION BETWEEN 2 ACR. OPERATIONAL ERROR.

Narrative: OUR FLT, ACR X, WAS DSNDING FROM ALT WHILE FLYING A DIRECT COURSE TO THE BOULDER CITY VOR FOR LNDG IN LAS. THE F/O WAS FLYING AND I WAS ON THE RADIO ZLA GAVE US A 10 DEG COURSE CHANGE TO THE LEFT FOR TFC AS WE WERE PASSING APPROX 26000'. A FEW MINS LATER WE WERE GIVEN ANOTHER 15 DEG LEFT VECTOR FOR COMPANY TFC THAT WAS CLBING OUT OF LAS. THE CTLR CALLED THE POS OF OUR TFC AND I COULD SEE THE OTHER MLG. IT APPEARED TO BE ABOUT 3 MI AWAY, AND LOOKED LIKE IT WOULD PASS WELL TO OUR RIGHT. AT ABOUT THAT TIME, AS WE WERE PASSING 21500', THE CTLR SUDDENLY TOLD US TO LEVEL AT FL220 AND OUR COMPANY FLT TO STOP HIS CLB AT FL210. WE STOPPED OUR DSCNT AT ABOUT FL210 AS OUR COMPANY PASSED ABEAM 2-3 MI AWAY. WHEN WE WERE TOLD TO STOP AT FL220 I TOLD THE CTLR WE WERE ALREADY AT 21500'. AFTER WE PASSED I ASKED THE CTLR IF HE WANTED US TO CONTINUE OUR DSCNT AND HE SAID YES. I SAW THE OTHER ACFT FOR SOME TIME BEFORE AND AS WE PASSED, AND NEVER FELT THERE WAS ANY CONFLICT. THE CTLR SOUNDED PRETTY TENSE ABOUT IT WHEN HE GAVE US OUR LATE LEVEL OFF CALL. I'M NOT SURE WHAT THE PROB WAS. EVIDENTLY THE CTLR DIDN'T SEE UNTIL TOO LATE THAT ON OUR VECTORS, WE WOULD NOT KEEP MINIMUM SEP ALTHOUGH IT LOOKED TO ME AS THOUGH WE HAD MORE THAN ENOUGH SEP THE WHOLE TIME.

Data retrieved from NASA's ASRS site as of August 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.