Air carrier Y descent through occupied altitude had less than standard separation with air carrier X...

Attributes
ACN	245786
Time
Date	199307
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : hvq
State Reference	WV
Altitude	msl bound lower : 31000 msl bound upper : 32500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 2
ASRS Report	245786
Person 2
Affiliation	government : faa
Function	oversight : supervisor
Qualification	controller : radar
Experience	controller radar : 15 controller supervisory : 8
ASRS Report	245653
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	atc equipment other atc equipment : unspecified
Resolutory Action	none taken : insufficient time
Consequence	faa : investigated
Miss Distance	horizontal : 24000 vertical : 1500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error Inter Facility Coordination Failure

Narrative:

Air carrier X climbed at 500 FPM from FL300 to FL390. Air carrier Y was descended from FL330 to FL290 and it descended at 500 FPM. Computer information led radar controller to believe that standard separation would be maintained. Lengthy landline communications reduced the evasive action window. When computer re- evaluated the information, conflict alert engaged 13 seconds prior to aedp. Insufficient time was had to re-establish standard separation. An inaccurate future presentation convinced radar controller that no turns or further instructions/clrncs were necessary. Standard separation was lost. Supplemental information from acn 245653: air carrier Y was being descended through the flight path of air carrier X. Lateral separation was not maintained before vertical separation was established. Controller did not realize the proximity of the flight paths until it was too late to re-establish lateral.

Original NASA ASRS Text

Title: ACR Y DSCNT THROUGH OCCUPIED ALT HAD LTSS WITH ACR X. SYS ERROR.

Narrative: ACR X CLBED AT 500 FPM FROM FL300 TO FL390. ACR Y WAS DSNDED FROM FL330 TO FL290 AND IT DSNDED AT 500 FPM. COMPUTER INFO LED RADAR CTLR TO BELIEVE THAT STANDARD SEPARATION WOULD BE MAINTAINED. LENGTHY LANDLINE COMS REDUCED THE EVASIVE ACTION WINDOW. WHEN COMPUTER RE- EVALUATED THE INFO, CONFLICT ALERT ENGAGED 13 SECONDS PRIOR TO AEDP. INSUFFICIENT TIME WAS HAD TO RE-ESTABLISH STANDARD SEPARATION. AN INACCURATE FUTURE PRESENTATION CONVINCED RADAR CTLR THAT NO TURNS OR FURTHER INSTRUCTIONS/CLRNCS WERE NECESSARY. STANDARD SEPARATION WAS LOST. SUPPLEMENTAL INFORMATION FROM ACN 245653: ACR Y WAS BEING DSNDED THROUGH THE FLT PATH OF ACR X. LATERAL SEPARATION WAS NOT MAINTAINED BEFORE VERT SEPARATION WAS ESTABLISHED. CTLR DID NOT REALIZE THE PROX OF THE FLT PATHS UNTIL IT WAS TOO LATE TO RE-ESTABLISH LATERAL.

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.

Air carrier Y descent through occupied altitude had less than standard separation with air carrier X. System error.