Sgf approach controller experienced loss of separation with BE58 and PA28 at 7000 ft cruise.

Attributes
ACN	585081
Time
Date	200306
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : sgf.airport
State Reference	MO
Altitude	msl single value : 7000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sgf.tracon
Operator	general aviation : personal
Make Model Name	Baron 58/58TC
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : sgf.tracon
Operator	general aviation : personal
Make Model Name	PA-28 Cherokee/Archer II/Dakota/Pillan/Warrior
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar pilot : instrument
Experience	controller limited radar : 1 controller military : 5 controller radar : 22 controller supervisory : 10 controller time certified in position1 : 6.5 flight time total : 1000
ASRS Report	585081
Person 2
Affiliation	other
Function	flight crew : single pilot
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	atc equipment : conflict alert other controllera
Resolutory Action	controller : issued alert controller : issued new clearance flight crew : took evasive action
Consequence	faa : investigated
Miss Distance	horizontal : 6000 vertical : 100
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

I was controling numerous aircraft on several frequencys. There was considerable frequency congestion and blocked xmissions. There were other controllers available, but a decision was made to use a coordinator rather than splitting the sector. There was too much to keep track of. Probably 15 aircraft with 1 military beech jet/T1 conducting high approachs down through en route traffic. 1 aircraft, a piper cherokee was IFR en route to a satellite airport heading southeast at 7000 ft and a beech baron IFR northeast en route overflt to 1HO, st louis, mo, area. Came within 1 mi and 100 ft separation. The conflict alert brought my attention to the 2 aircraft. Had it not been operational, the result may have been catastrophic. I issued a traffic alert first to the barron who did not immediately comply. I reissued the alert a second and third time before I issued a traffic alert to the cherokee. There was too much traffic for 1 controller to safely handle. I should have asked to split position. As for pilots, when you hear a safety alert, be ready to act. It may save your life.

Original NASA ASRS Text

Title: SGF APCH CTLR EXPERIENCED LOSS OF SEPARATION WITH BE58 AND PA28 AT 7000 FT CRUISE.

Narrative: I WAS CTLING NUMEROUS ACFT ON SEVERAL FREQS. THERE WAS CONSIDERABLE FREQ CONGESTION AND BLOCKED XMISSIONS. THERE WERE OTHER CTLRS AVAILABLE, BUT A DECISION WAS MADE TO USE A COORDINATOR RATHER THAN SPLITTING THE SECTOR. THERE WAS TOO MUCH TO KEEP TRACK OF. PROBABLY 15 ACFT WITH 1 MIL BEECH JET/T1 CONDUCTING HIGH APCHS DOWN THROUGH ENRTE TFC. 1 ACFT, A PIPER CHEROKEE WAS IFR ENRTE TO A SATELLITE ARPT HEADING SE AT 7000 FT AND A BEECH BARON IFR NE ENRTE OVERFLT TO 1HO, ST LOUIS, MO, AREA. CAME WITHIN 1 MI AND 100 FT SEPARATION. THE CONFLICT ALERT BROUGHT MY ATTN TO THE 2 ACFT. HAD IT NOT BEEN OPERATIONAL, THE RESULT MAY HAVE BEEN CATASTROPHIC. I ISSUED A TFC ALERT FIRST TO THE BARRON WHO DID NOT IMMEDIATELY COMPLY. I REISSUED THE ALERT A SECOND AND THIRD TIME BEFORE I ISSUED A TFC ALERT TO THE CHEROKEE. THERE WAS TOO MUCH TFC FOR 1 CTLR TO SAFELY HANDLE. I SHOULD HAVE ASKED TO SPLIT POS. AS FOR PLTS, WHEN YOU HEAR A SAFETY ALERT, BE READY TO ACT. IT MAY SAVE YOUR LIFE.

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.