Aircraft was descended through an occupied altitude resulting in less than standard separation.

Attributes
ACN	124846
Time
Date	198910
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : stl
State Reference	MO
Altitude	msl bound lower : 9000 msl bound upper : 9000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zkc
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	descent other
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
ASRS Report	124846
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument
Events
Anomaly	non adherence : required legal separation non adherence : published procedure
Independent Detector	other controllera
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Miss Distance	horizontal : 24000 vertical : 500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Small aircraft X was descended through small aircraft Y's altitude with less than 5 mi separation.

Original NASA ASRS Text

Title: ACFT WAS DESCENDED THROUGH AN OCCUPIED ALT RESULTING IN LESS THAN STANDARD SEPARATION.

Narrative: SMA X WAS DESCENDED THROUGH SMA Y'S ALT WITH LESS THAN 5 MI SEPARATION.

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.