Less than standard separation between air carrier X and Y. System error.

Attributes
ACN	127545
Time
Date	198911
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : tys
State Reference	TN
Altitude	msl bound lower : 12500 msl bound upper : 12500
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : ztl
Operator	common carrier : air carrier
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Flight Phase	descent other
Route In Use	arrival other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
ASRS Report	127545
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	atc equipment other atc equipment : unspecified
Resolutory Action	none taken : detected after the fact
Consequence	faa : investigated
Miss Distance	horizontal : 6000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Descending air carrier X into tri with crossing restriction at or below 12000' in 1 1/2 mins. Climbing air carrier Y with restriction at or above 13000' in 1 1/2 mins. Air carrier Y misread clearance. I reissued clearance to air carrier Y at or above 13000' in about 1 min. Phraseology error and too late at this point to get sep. Discovered by C/a. I was decertified, pending investigation. No evasive action required. Poor communication between controller and air carrier Y contributed to error. Need more timely clearance and better listening by pilots to avoid this type of error. Poor timing on my part.

Original NASA ASRS Text

Title: LESS THAN STANDARD SEPARATION BETWEEN ACR X AND Y. SYSTEM ERROR.

Narrative: DSNDING ACR X INTO TRI WITH XING RESTRICTION AT OR BELOW 12000' IN 1 1/2 MINS. CLBING ACR Y WITH RESTRICTION AT OR ABOVE 13000' IN 1 1/2 MINS. ACR Y MISREAD CLRNC. I REISSUED CLRNC TO ACR Y AT OR ABOVE 13000' IN ABOUT 1 MIN. PHRASEOLOGY ERROR AND TOO LATE AT THIS POINT TO GET SEP. DISCOVERED BY C/A. I WAS DECERTIFIED, PENDING INVESTIGATION. NO EVASIVE ACTION REQUIRED. POOR COM BTWN CTLR AND ACR Y CONTRIBUTED TO ERROR. NEED MORE TIMELY CLRNC AND BETTER LISTENING BY PLTS TO AVOID THIS TYPE OF ERROR. POOR TIMING ON MY PART.

Data retrieved from NASA's ASRS site as of August 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.