Operational error. Air carrier X less than standard separation from air carrier Y system error.

Attributes
ACN	289419
Time
Date	199411
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : hvq
State Reference	WV
Altitude	msl bound lower : 25000 msl bound upper : 25000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zdc artcc : zid
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 121
Flight Phase	cruise other descent other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 17
ASRS Report	289419
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 other atc equipment : unspecified
Resolutory Action	none taken : detected after the fact
Consequence	Other
Miss Distance	horizontal : 27000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Air carrier X was on frequency at FL260. Air carrier Y came on frequency at FL260 10 mi intrail and overtaking by 30 KTS. I asked both aircraft their speed and was unable to increase air carrier X. I got control to descend air carrier X and I descended him to FL250. However, conflict alert activated with air carrier X and air carrier Z an aircraft being worked by ZDC. I turned air carrier X right to a 360 degree heading. Callback conversation with reporter revealed the following information: reporter indicated that he had previously switched the conflicting traffic to the adjacent center prior to interfacility coordination for the lower altitude. It appears that approval was obtained but reporter stated that the controller had based it on the previous aircraft which was at the same altitude required. Reporter indicated that he did not hear the information about the traffic as he was clearing air carrier X to the lower altitude. He indicated that the data block of air carrier Z may have been covered by other traffic and not visible when the descent clearance was issued.

Original NASA ASRS Text

Title: OPERROR. ACR X LTSS FROM ACR Y SYS ERROR.

Narrative: ACR X WAS ON FREQ AT FL260. ACR Y CAME ON FREQ AT FL260 10 MI INTRAIL AND OVERTAKING BY 30 KTS. I ASKED BOTH ACFT THEIR SPD AND WAS UNABLE TO INCREASE ACR X. I GOT CTL TO DSND ACR X AND I DSNDED HIM TO FL250. HOWEVER, CONFLICT ALERT ACTIVATED WITH ACR X AND ACR Z AN ACFT BEING WORKED BY ZDC. I TURNED ACR X R TO A 360 DEG HDG. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR INDICATED THAT HE HAD PREVIOUSLY SWITCHED THE CONFLICTING TFC TO THE ADJACENT CTR PRIOR TO INTERFAC COORD FOR THE LOWER ALT. IT APPEARS THAT APPROVAL WAS OBTAINED BUT RPTR STATED THAT THE CTLR HAD BASED IT ON THE PREVIOUS ACFT WHICH WAS AT THE SAME ALT REQUIRED. RPTR INDICATED THAT HE DID NOT HEAR THE INFO ABOUT THE TFC AS HE WAS CLRING ACR X TO THE LOWER ALT. HE INDICATED THAT THE DATA BLOCK OF ACR Z MAY HAVE BEEN COVERED BY OTHER TFC AND NOT VISIBLE WHEN THE DSCNT CLRNC WAS ISSUED.

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.