Air carrier descended to an occupied altitude resulting in less than standard separation.

Attributes
ACN	140819
Time
Date	199003
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : bpr
State Reference	TX
Altitude	msl bound lower : 24000 msl bound upper : 25000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zfw artcc : zmp
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent other
Route In Use	arrival other
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	descent other
Route In Use	arrival other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 120 flight time total : 3200 flight time type : 1000
ASRS Report	140819
Person 2
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 170 flight time total : 2500 flight time type : 650
ASRS Report	130235
Events
Anomaly	altitude deviation : overshoot non adherence : published procedure non adherence : required legal separation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance
Consequence	Other
Miss Distance	horizontal : 12000 vertical : 500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Clear to descend to FL250 from FL330 then to FL2400. Could see air carrier Y lower and to the left of us. After telling air carrier Y to descend several times and no respond, they told us to stop our descent and slow 250 KTS. We were about FL24.6 and stopped at FL24.4. Air carrier Y finally responded and was cleared to 7000'. We were later cleared to 10000' normal speed and expect 9000' at boids and turn over to regulation approach. Supplemental information from acn 140235. We were told to level immediately while in an assigned descent. Apparently the other aircraft was slow to vacate his altitude due to some radio problems. We had the other aircraft visually.

Original NASA ASRS Text

Title: ACR DESCENDED TO AN OCCUPIED ALT RESULTING IN LESS THAN STANDARD SEPARATION.

Narrative: CLR TO DSND TO FL250 FROM FL330 THEN TO FL2400. COULD SEE ACR Y LOWER AND TO THE L OF US. AFTER TELLING ACR Y TO DSND SEVERAL TIMES AND NO RESPOND, THEY TOLD US TO STOP OUR DSCNT AND SLOW 250 KTS. WE WERE ABOUT FL24.6 AND STOPPED AT FL24.4. ACR Y FINALLY RESPONDED AND WAS CLRED TO 7000'. WE WERE LATER CLRED TO 10000' NORMAL SPD AND EXPECT 9000' AT BOIDS AND TURN OVER TO REG APCH. SUPPLEMENTAL INFO FROM ACN 140235. WE WERE TOLD TO LEVEL IMMEDIATELY WHILE IN AN ASSIGNED DSCNT. APPARENTLY THE OTHER ACFT WAS SLOW TO VACATE HIS ALT DUE TO SOME RADIO PROBS. WE HAD THE OTHER ACFT VISUALLY.

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.