Air carrier X descent through occupied altitude had less than standard separation from air carrier Y...

Attributes
ACN	241198
Time
Date	199305
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : buj
State Reference	TX
Altitude	msl bound lower : 29000 msl bound upper : 31000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zfw tower : gmu
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	Light Transport, Low Wing, 2 Turboprop Eng
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 non radar : 2 controller radar : 3
ASRS Report	241198
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 : anomaly accepted
Consequence	faa : investigated
Miss Distance	horizontal : 24000 vertical : 1600
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Air carrier X inbound on BUJ3 (swbound). Air carrier Y turboprop nebound FL290, crossing in front of air carrier X I descended air carrier X thinking I had met all requirements of the 'in-sight passing' rule, when in fact that may not have been the case. Gave supervisor this rule when the area manager called, and no further action was taken. The distraction of dealing with 'faulty' radio frequency may have partially led me to believe I was correctly using the rule. I am sure I issued air carrier X traffic but am only somewhat positive of air carrier X response he had passed traffic. I was issuing numerous traffic calls and may have missed issuing air carrier X the traffic. Knowing I wanted to use this rule, I thought I had and also had heard air carrier X report passing air carrier Y then descended air carrier X, not sure air carrier Y was on frequency as required either. All these doubts arise after the fact, but at the time of the incident, I am sure I was 'legal' in my clrncs.

Original NASA ASRS Text

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

Narrative: ACR X INBOUND ON BUJ3 (SWBOUND). ACR Y TURBOPROP NEBOUND FL290, XING IN FRONT OF ACR X I DSNDED ACR X THINKING I HAD MET ALL REQUIREMENTS OF THE 'IN-SIGHT PASSING' RULE, WHEN IN FACT THAT MAY NOT HAVE BEEN THE CASE. GAVE SUPVR THIS RULE WHEN THE AREA MGR CALLED, AND NO FURTHER ACTION WAS TAKEN. THE DISTR OF DEALING WITH 'FAULTY' RADIO FREQ MAY HAVE PARTIALLY LED ME TO BELIEVE I WAS CORRECTLY USING THE RULE. I AM SURE I ISSUED ACR X TFC BUT AM ONLY SOMEWHAT POSITIVE OF ACR X RESPONSE HE HAD PASSED TFC. I WAS ISSUING NUMEROUS TFC CALLS AND MAY HAVE MISSED ISSUING ACR X THE TFC. KNOWING I WANTED TO USE THIS RULE, I THOUGHT I HAD AND ALSO HAD HEARD ACR X RPT PASSING ACR Y THEN DSNDED ACR X, NOT SURE ACR Y WAS ON FREQ AS REQUIRED EITHER. ALL THESE DOUBTS ARISE AFTER THE FACT, BUT AT THE TIME OF THE INCIDENT, I AM SURE I WAS 'LEGAL' IN MY CLRNCS.

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 through occupied altitude had less than standard separation from air carrier Y. System error.