Standard separation was not maintained between 2 aircraft under the control of ATC controller.

Attributes
ACN	145934
Time
Date	199005
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : vrb
State Reference	FL
Altitude	msl bound lower : 35000 msl bound upper : 36500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zma
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other descent other
Route In Use	arrival other enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Route In Use	arrival other enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
ASRS Report	145934
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	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Miss Distance	horizontal : 18000 vertical : 1500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error Pilot Deviation

Narrative:

Large transport was heading 090 degrees level at FL370. Medium large transport was heading 160 degrees at FL350. Large transport approximately 10 mi west of medium large transport was issued right turn to heading 180 degrees, descend and maintain FL240. Aircraft appeared to be slow turning and was getting close to medium large transport. Large transport had not reported leaving altitude and mode C indicated still level so I re-restr large transport to maintain FL370. Pilot said aircraft would return to FL370 and mode C then update. I believe if the pilot had reported leaving FL370, the other aircraft could have been issued a lower altitude and sep maintained.

Original NASA ASRS Text

Title: STANDARD SEPARATION WAS NOT MAINTAINED BETWEEN 2 ACFT UNDER THE CONTROL OF ATC CTLR.

Narrative: LGT WAS HDG 090 DEGS LEVEL AT FL370. MLG WAS HDG 160 DEGS AT FL350. LGT APPROX 10 MI W OF MLG WAS ISSUED RIGHT TURN TO HDG 180 DEGS, DSND AND MAINTAIN FL240. ACFT APPEARED TO BE SLOW TURNING AND WAS GETTING CLOSE TO MLG. LGT HAD NOT RPTED LEAVING ALT AND MODE C INDICATED STILL LEVEL SO I RE-RESTR LGT TO MAINTAIN FL370. PLT SAID ACFT WOULD RETURN TO FL370 AND MODE C THEN UPDATE. I BELIEVE IF THE PLT HAD RPTED LEAVING FL370, THE OTHER ACFT COULD HAVE BEEN ISSUED A LOWER ALT AND SEP MAINTAINED.

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.