Aircraft X descent through occupied altitude, had less than standard separation from aircraft Y. Sys...

Attributes
ACN	260957
Time
Date	199401
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ape
State Reference	OH
Altitude	msl bound lower : 37000 msl bound upper : 37000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	descent other
Route In Use	enroute : direct
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
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	260957
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	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	faa : investigated
Miss Distance	horizontal : 16800 vertical : 400
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Aircraft X was nbwound iad-iad at FL390. Aircraft Y was sbound dtw-tpa at FL370. Aircraft Y was switched to next frequency then radar data block accidentally dropped. It is my feeling this was due to poor condition of old, well-worn computer key pad. Aircraft X was cleared to FL280 for arrival to ind and traffic. I saw the limited data block beneath the descending aircraft and immediately issued a turn clearance. I also told controller talking to aircraft Y to turn him as well. Separation was lost and reestablished before the turns could take effect.

Original NASA ASRS Text

Title: ACFT X DSCNT THROUGH OCCUPIED ALT, HAD LTSS FROM ACFT Y. SYS ERROR.

Narrative: ACFT X WAS NBWOUND IAD-IAD AT FL390. ACFT Y WAS SBOUND DTW-TPA AT FL370. ACFT Y WAS SWITCHED TO NEXT FREQ THEN RADAR DATA BLOCK ACCIDENTALLY DROPPED. IT IS MY FEELING THIS WAS DUE TO POOR CONDITION OF OLD, WELL-WORN COMPUTER KEY PAD. ACFT X WAS CLRED TO FL280 FOR ARR TO IND AND TFC. I SAW THE LIMITED DATA BLOCK BENEATH THE DSNDING ACFT AND IMMEDIATELY ISSUED A TURN CLRNC. I ALSO TOLD CTLR TALKING TO ACFT Y TO TURN HIM AS WELL. SEPARATION WAS LOST AND REESTABLISHED BEFORE THE TURNS COULD TAKE EFFECT.

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.

Aircraft X descent through occupied altitude, had less than standard separation from aircraft Y. System error.