Conflict occurred when a ZID ARTCC radar controller descended traffic through an occupied altitude.

Attributes
ACN	609613
Time
Date	200402
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : pxv.vortac
State Reference	IN
Altitude	msl bound lower : 28000 msl bound upper : 29000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid.artcc
Operator	common carrier : air carrier
Make Model Name	EMB ERJ 145 ER&LR
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	descent : intermediate altitude
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zid.artcc
Operator	common carrier : air carrier
Make Model Name	Avro RJ85
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 12 controller time certified in position1 : 5
ASRS Report	609613
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	conflict : airborne critical non adherence : required legal separation non adherence : published procedure
Independent Detector	atc equipment : conflict alert atc equipment other atc equipment : radar mode c other controllera other flight crewa other flight crewb
Consequence	faa : investigated
Miss Distance	horizontal : 16200 vertical : 600
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

I thought aircraft Y was level at FL310 when he was really at FL280. I started aircraft X down to FL240 from FL290 and had error with other aircraft.

Original NASA ASRS Text

Title: CONFLICT OCCURRED WHEN A ZID ARTCC RADAR CTLR DSNDED TFC THROUGH AN OCCUPIED ALT.

Narrative: I THOUGHT ACFT Y WAS LEVEL AT FL310 WHEN HE WAS REALLY AT FL280. I STARTED ACFT X DOWN TO FL240 FROM FL290 AND HAD ERROR WITH OTHER ACFT.

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.