Air carrier X had less than standard separation from air carrier Y. System error.

Attributes
ACN	133992
Time
Date	199001
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : fsm
State Reference	AR
Altitude	msl bound lower : 26000 msl bound upper : 27000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zme
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent other
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : flight data
Qualification	controller : radar
Experience	controller military : 4 controller radar : 21
ASRS Report	133992
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
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	other
Consequence	faa : investigated
Miss Distance	horizontal : 15000 vertical : 700
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Sector very busy due to WX in area, rerouting aircraft to and from dfw area. With WX like it was this sector is busy all the time. With 2 to 3 days of traffic rerouting aircraft due to WX, inputting altitude changes the manual controller was very busy as was the 'right' man. With 'right' man on landline as was 'D' man, air carrier X landing lit asked for lower. 'D' man was off first so after observing on radar scope the 2 targets looked as if they had passed. With data blocks overlapping they could look that way. The 'D' man descended air carrier X through altitude of the other air carrier Y. As soon as he gave the descent he answered yet another landline. The 'right' then was off and seen the conflict alert go off. He started separation but it was too late, when the conflict alert and snitch go off at the same time it's too late, they passed 700' and approximately 2 1/2 mi. Staffing in the west area of mem ARTCC was at minimum if not below it. It's like this just about all the time. We had no handoff man. If the area was staffed properly with extra people such as handoff man and relief person, I firmly believe this incident would have never happened. Callback conversation with reporter revealed the following: reporter experience: 21 yrs radar, 4 yrs military. The reporter was working the D position. The reporter stated he descended air carrier X without the radar controller's knowledge. Reporter says the D controller is authorized to do this if he is radar and sector qualified. The radar controller was not held at fault for the system error.

Original NASA ASRS Text

Title: ACR X HAD LESS THAN STANDARD SEPARATION FROM ACR Y. SYSTEM ERROR.

Narrative: SECTOR VERY BUSY DUE TO WX IN AREA, REROUTING ACFT TO AND FROM DFW AREA. WITH WX LIKE IT WAS THIS SECTOR IS BUSY ALL THE TIME. WITH 2 TO 3 DAYS OF TFC REROUTING ACFT DUE TO WX, INPUTTING ALT CHANGES THE MANUAL CTLR WAS VERY BUSY AS WAS THE 'R' MAN. WITH 'R' MAN ON LANDLINE AS WAS 'D' MAN, ACR X LNDG LIT ASKED FOR LOWER. 'D' MAN WAS OFF FIRST SO AFTER OBSERVING ON RADAR SCOPE THE 2 TARGETS LOOKED AS IF THEY HAD PASSED. WITH DATA BLOCKS OVERLAPPING THEY COULD LOOK THAT WAY. THE 'D' MAN DESCENDED ACR X THROUGH ALT OF THE OTHER ACR Y. AS SOON AS HE GAVE THE DSCNT HE ANSWERED YET ANOTHER LANDLINE. THE 'R' THEN WAS OFF AND SEEN THE CONFLICT ALERT GO OFF. HE STARTED SEPARATION BUT IT WAS TOO LATE, WHEN THE CONFLICT ALERT AND SNITCH GO OFF AT THE SAME TIME IT'S TOO LATE, THEY PASSED 700' AND APPROX 2 1/2 MI. STAFFING IN THE W AREA OF MEM ARTCC WAS AT MINIMUM IF NOT BELOW IT. IT'S LIKE THIS JUST ABOUT ALL THE TIME. WE HAD NO HANDOFF MAN. IF THE AREA WAS STAFFED PROPERLY WITH EXTRA PEOPLE SUCH AS HANDOFF MAN AND RELIEF PERSON, I FIRMLY BELIEVE THIS INCIDENT WOULD HAVE NEVER HAPPENED. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: REPORTER EXPERIENCE: 21 YRS RADAR, 4 YRS MIL. THE REPORTER WAS WORKING THE D POSITION. THE REPORTER STATED HE DESCENDED ACR X WITHOUT THE RADAR CTLR'S KNOWLEDGE. REPORTER SAYS THE D CTLR IS AUTHORIZED TO DO THIS IF HE IS RADAR AND SECTOR QUALIFIED. THE RADAR CTLR WAS NOT HELD AT FAULT FOR THE SYSTEM ERROR.

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.