Military X descent through occupied altitude had less than standard separation from air carrier Y. S...

Attributes
ACN	267768
Time
Date	199403
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : sbv
State Reference	VA
Altitude	msl bound lower : 21000 msl bound upper : 21000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc
Operator	other
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : other
Flight Phase	descent other
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Jetstream 31
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller non radar : 7 controller radar : 6
ASRS Report	267768
Person 2
Affiliation	government : military
Function	flight crew : captain oversight : pic
Qualification	pilot : military
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 : detected after the fact
Consequence	faa : investigated
Miss Distance	horizontal : 24000 vertical : 500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

I was assigned radar position at sector 22, with traffic volume and complexity increasing. The volume was approximately 20-21 aircraft, complexity was the rdv arrival sequencing with jet and propeller - gso arrival and departures, crossing and opposite direction traffic for both arrs. Military act X requested lower, I issued descent clearance after researching (scanning) his potential traffic being the rdv arrs opposite direction to him. The BA31 Y crossing traffic I didn't consider potential conflict. The difference in speed between 2 aircraft caused the BA31 to enter protected airspace of the air evacuate/evacuation with less than minimum separation. Just a few mins prior to the occurrence, I requested help in position of radar associate due to increasing volume and complexity and received it 1 min prior to incident. The conflict alert activated after (or as) separation was lost, there was no prior warning.

Original NASA ASRS Text

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

Narrative: I WAS ASSIGNED RADAR POS AT SECTOR 22, WITH TFC VOLUME AND COMPLEXITY INCREASING. THE VOLUME WAS APPROX 20-21 ACFT, COMPLEXITY WAS THE RDV ARR SEQUENCING WITH JET AND PROP - GSO ARR AND DEPS, XING AND OPPOSITE DIRECTION TFC FOR BOTH ARRS. MIL ACT X REQUESTED LOWER, I ISSUED DSCNT CLRNC AFTER RESEARCHING (SCANNING) HIS POTENTIAL TFC BEING THE RDV ARRS OPPOSITE DIRECTION TO HIM. THE BA31 Y XING TFC I DIDN'T CONSIDER POTENTIAL CONFLICT. THE DIFFERENCE IN SPD BTWN 2 ACFT CAUSED THE BA31 TO ENTER PROTECTED AIRSPACE OF THE AIR EVAC WITH LESS THAN MINIMUM SEPARATION. JUST A FEW MINS PRIOR TO THE OCCURRENCE, I REQUESTED HELP IN POS OF RADAR ASSOCIATE DUE TO INCREASING VOLUME AND COMPLEXITY AND RECEIVED IT 1 MIN PRIOR TO INCIDENT. THE CONFLICT ALERT ACTIVATED AFTER (OR AS) SEPARATION WAS LOST, THERE WAS NO PRIOR WARNING.

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.

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