Approach controller failed to provide standard radar separation between 2 aircraft under his control...

Attributes
ACN	161542
Time
Date	199010
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : atl
State Reference	GA
Altitude	msl bound lower : 6000 msl bound upper : 6400
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : atl
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Navigation In Use	Other
Flight Phase	descent other
Route In Use	arrival other enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 3600 flight time type : 1600
ASRS Report	161542
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 6500 flight time type : 2500
ASRS Report	161297
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
Consequence	Other
Miss Distance	horizontal : 9000 vertical : 400
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

We contacted atl approach at 236.9 at 40 NM and 9000' coming from the northeast. While being vectored for a visibility to runway 26R we were given a descent to 6000' and told to contact atl approach on 118.35. We contacted approach while passing 6800' because they were extremely busy at the time. We were instructed to climb immediately back to 7000' because of traffic at 2 O'clock and 6000' (medium large transport) and we were also told to contact approach on 127.25. We did as instructed and the flight was completed west/O further incident. I really have no explanation for the medium large transport and us ending up so close together except for a controller mixup. I do think that a factor in this incident was that atl approach sometimes consolidates approach frequencys (north/south), but you as a crew don't ever know it. So when approach gave us 118.35 for final approach we didn't question, even though final approach from the north is 127.25 when both frequencys are working. It would be very helpful if the crews could know ahead of time if north/south approachs have been consolidated to 1 frequency.

Original NASA ASRS Text

Title: APCH CTLR FAILED TO PROVIDE STANDARD RADAR SEPARATION BETWEEN 2 ACFT UNDER HIS CTL.

Narrative: WE CONTACTED ATL APCH AT 236.9 AT 40 NM AND 9000' COMING FROM THE NE. WHILE BEING VECTORED FOR A VIS TO RWY 26R WE WERE GIVEN A DSNT TO 6000' AND TOLD TO CONTACT ATL APCH ON 118.35. WE CONTACTED APCH WHILE PASSING 6800' BECAUSE THEY WERE EXTREMELY BUSY AT THE TIME. WE WERE INSTRUCTED TO CLB IMMEDIATELY BACK TO 7000' BECAUSE OF TFC AT 2 O'CLOCK AND 6000' (MLG) AND WE WERE ALSO TOLD TO CONTACT APCH ON 127.25. WE DID AS INSTRUCTED AND THE FLT WAS COMPLETED W/O FURTHER INCIDENT. I REALLY HAVE NO EXPLANATION FOR THE MLG AND US ENDING UP SO CLOSE TOGETHER EXCEPT FOR A CTLR MIXUP. I DO THINK THAT A FACTOR IN THIS INCIDENT WAS THAT ATL APCH SOMETIMES CONSOLIDATES APCH FREQS (N/S), BUT YOU AS A CREW DON'T EVER KNOW IT. SO WHEN APCH GAVE US 118.35 FOR FINAL APCH WE DIDN'T QUESTION, EVEN THOUGH FINAL APCH FROM THE N IS 127.25 WHEN BOTH FREQS ARE WORKING. IT WOULD BE VERY HELPFUL IF THE CREWS COULD KNOW AHEAD OF TIME IF N/S APCHS HAVE BEEN CONSOLIDATED TO 1 FREQ.

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.