Air carrier X descent to occupied altitude had less than standard separation from aircraft Y. System...

Attributes
ACN	260220
Time
Date	199401
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : orl
State Reference	FL
Altitude	msl bound lower : 9000 msl bound upper : 9000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : mco
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
Route In Use	arrival other
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller radar : 6
ASRS Report	260220
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 15000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

On this day, I was working arrival radar with 2 sectors combined. Traffic was heavy due to a holiday wkend and we had been busy all day. I had worked several overflts and had handed them off to the next sector. As aircraft left my airspace, I no longer watched the data tags. I had forgotten about a single engine aircraft Y northbound at 9000 ft handing off but still in my airspace. I descended an air carrier on the arrival to 9000 ft. I then started to give a relief briefing to the next controller. I did not include the single engine aircraft Y because I was no longer watching the data tag. The air carrier X reported responding to a TCASII alert and reported the other aircraft visually. The air carrier X passed behind the single engine aircraft Y.

Original NASA ASRS Text

Title: ACR X DSCNT TO OCCUPIED ALT HAD LTSS FROM ACFT Y. SYS ERROR.

Narrative: ON THIS DAY, I WAS WORKING ARR RADAR WITH 2 SECTORS COMBINED. TFC WAS HVY DUE TO A HOLIDAY WKEND AND WE HAD BEEN BUSY ALL DAY. I HAD WORKED SEVERAL OVERFLTS AND HAD HANDED THEM OFF TO THE NEXT SECTOR. AS ACFT LEFT MY AIRSPACE, I NO LONGER WATCHED THE DATA TAGS. I HAD FORGOTTEN ABOUT A SINGLE ENG ACFT Y NBOUND AT 9000 FT HANDING OFF BUT STILL IN MY AIRSPACE. I DSNDED AN ACR ON THE ARR TO 9000 FT. I THEN STARTED TO GIVE A RELIEF BRIEFING TO THE NEXT CTLR. I DID NOT INCLUDE THE SINGLE ENG ACFT Y BECAUSE I WAS NO LONGER WATCHING THE DATA TAG. THE ACR X RPTED RESPONDING TO A TCASII ALERT AND RPTED THE OTHER ACFT VISUALLY. THE ACR X PASSED BEHIND THE SINGLE ENG ACFT Y.

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 X descent to occupied altitude had less than standard separation from aircraft Y. System error.