Aircraft Y, which was the faster aircraft, overtook aircraft X. Separation lost.

Attributes
ACN	428810
Time
Date	199901
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : mcw.vortac
State Reference	IA
Altitude	msl single value : 23000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zmp.artcc
Operator	common carrier : air carrier
Make Model Name	DC-9 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : enroute altitude change descent : intermediate altitude
Route In Use	arrival star : ns
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zmp.artcc
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : enroute altitude change descent : intermediate altitude
Route In Use	arrival star : ns
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 9
ASRS Report	428810
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation non adherence : published procedure
Independent Detector	atc equipment : conflict alert
Resolutory Action	none taken : anomaly accepted
Consequence	faa : investigated
Miss Distance	horizontal : 24000 vertical : 300
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Aircraft #2 (Y) was following aircraft #1 (X) on a STAR into msp. Aircraft #2 (Y) was 40 KTS faster and caught aircraft #1 (X) without vertical separation established.

Original NASA ASRS Text

Title: ACFT Y, WHICH WAS THE FASTER ACFT, OVERTOOK ACFT X. SEPARATION LOST.

Narrative: ACFT #2 (Y) WAS FOLLOWING ACFT #1 (X) ON A STAR INTO MSP. ACFT #2 (Y) WAS 40 KTS FASTER AND CAUGHT ACFT #1 (X) WITHOUT VERT SEPARATION ESTABLISHED.

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.