Operational error between aircraft X and aircraft Y. System error.

Attributes
ACN	281317
Time
Date	199408
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : cmh
State Reference	OH
Altitude	msl bound lower : 31400 msl bound upper : 33000
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zid
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : unknown
Flight Phase	cruise other
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : unknown
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 2
ASRS Report	281317
Person 2
Function	flight crew : single pilot
Qualification	pilot : private pilot : instrument
Events
Anomaly	non adherence : required legal separation non adherence : published procedure
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance
Consequence	Other
Miss Distance	horizontal : 25200 vertical : 1600
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Aircraft X called on frequency. I turned him 10 degree left because of possible traffic with aircraft Y and another aircraft. Aircraft X was issued a clearance to FL330. Aircraft Y called on out of FL330 for FL310. I saw aircraft Y's altitude to read FL312 and issued a clearance to aircraft X back direct hickory. I then cleared aircraft Y to FL290. Conflict alert activated and I asked aircraft Y to verify level at FL310. He called back out of FL314 for FL290. I asked aircraft Y to say altitude leaving. He said leaving FL314 for FL290. Aircraft Y called back asking for verification of assigned altitude. I told aircraft Y the clearance was to FL29O. He called back leaving FL310 for FL290.

Original NASA ASRS Text

Title: OPERROR BTWN ACFT X AND ACFT Y. SYS ERROR.

Narrative: ACFT X CALLED ON FREQ. I TURNED HIM 10 DEG L BECAUSE OF POSSIBLE TFC WITH ACFT Y AND ANOTHER ACFT. ACFT X WAS ISSUED A CLRNC TO FL330. ACFT Y CALLED ON OUT OF FL330 FOR FL310. I SAW ACFT Y'S ALT TO READ FL312 AND ISSUED A CLRNC TO ACFT X BACK DIRECT HICKORY. I THEN CLRED ACFT Y TO FL290. CONFLICT ALERT ACTIVATED AND I ASKED ACFT Y TO VERIFY LEVEL AT FL310. HE CALLED BACK OUT OF FL314 FOR FL290. I ASKED ACFT Y TO SAY ALT LEAVING. HE SAID LEAVING FL314 FOR FL290. ACFT Y CALLED BACK ASKING FOR VERIFICATION OF ASSIGNED ALT. I TOLD ACFT Y THE CLRNC WAS TO FL29O. HE CALLED BACK LEAVING FL310 FOR FL290.

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.