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

Attributes
ACN	154760
Time
Date	199008
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : vhp
State Reference	IN
Altitude	msl bound lower : 27800 msl bound upper : 28000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude descent other
Route In Use	enroute : on vectors
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
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 6200 flight time type : 340
ASRS Report	154760
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance other
Consequence	faa : investigated
Miss Distance	horizontal : 12000 vertical : 200
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

We were operating air carrier X from ind to den. We were assigned a heading of 260 degree vector for traffic and told to climb and maintain FL280. As we climbed out of FL278 the controller said in an excited voice, 'air carrier X, say altitude.' we told him FL278 climbing to FL280. His response was air carrier X immediately descend to FL270. He pointed out air carrier Y medium large transport at 12 O'clock position about 2 mi opp direction at FL280. We immediately descended to FL270 and nothing else was said. The air traffic controller was busy that morning talking to numerous aircraft on I think 2 frequencys. Our course and route of flight was about 270 degrees which is an even altitude. Why the controller had conflicting eastbound traffic on an even altitude is unknown to me, I think controllers should adhere more strictly to the westbound even altitude, eastbound odd altitude rule.

Original NASA ASRS Text

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

Narrative: WE WERE OPERATING ACR X FROM IND TO DEN. WE WERE ASSIGNED A HDG OF 260 DEG VECTOR FOR TFC AND TOLD TO CLB AND MAINTAIN FL280. AS WE CLBED OUT OF FL278 THE CTLR SAID IN AN EXCITED VOICE, 'ACR X, SAY ALT.' WE TOLD HIM FL278 CLBING TO FL280. HIS RESPONSE WAS ACR X IMMEDIATELY DSND TO FL270. HE POINTED OUT ACR Y MLG AT 12 O'CLOCK POS ABOUT 2 MI OPP DIRECTION AT FL280. WE IMMEDIATELY DSNDED TO FL270 AND NOTHING ELSE WAS SAID. THE AIR TFC CTLR WAS BUSY THAT MORNING TALKING TO NUMEROUS ACFT ON I THINK 2 FREQS. OUR COURSE AND RTE OF FLT WAS ABOUT 270 DEGS WHICH IS AN EVEN ALT. WHY THE CTLR HAD CONFLICTING EBND TFC ON AN EVEN ALT IS UNKNOWN TO ME, I THINK CTLRS SHOULD ADHERE MORE STRICTLY TO THE WBND EVEN ALT, EBND ODD ALT RULE.

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.