Potential conflict in a night operation. Altitude heading track deviation.

Attributes
ACN	297871
Time
Date	199503
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : atl
State Reference	GA
Altitude	msl bound lower : 6000 msl bound upper : 8000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : atl tower : sat
Operator	common carrier : air carrier
Make Model Name	MD-88
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	MD-88
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : instrument pilot : commercial
Experience	flight time last 90 days : 90 flight time total : 5000 flight time type : 3500
ASRS Report	297871
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance non adherence : required legal separation other anomaly other other spatial deviation
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance flight crew : exited adverse environment flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 12000 vertical : 100
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were flight (M-88), 20 NM northeast of atl, being vectored for approach (ILS 26R) by atl approach. We were at 8000 ft, 210 KIAS, heading 230 degrees. Approach directed us to turn to a 180 degree heading, to descend to 6000 ft and then slow to 180 KIAS. We were then given a frequency change. We were unable to 'check in' immediately due to the high volume of communication. At this point we were asked our assigned heading by approach control and simultaneously received a TCASII TA. The TCASII showed traffic at 1 O'clock and 100 ft low. The range was just outside the 'mid-scale' ring on the radar screen display. I don't recall if I was in 5 or 10 mi scale. We began to initiate a left turn, and were directed by approach to immediately turn left to heading 090 degrees and climb to 7000 ft. We did as instructed and after the turn and climb no further action was taken or necessary. I do not recall receiving a TCASII RA. I did see aircraft lights at our 1 O'clock position when initiating the evasive turn, but due to night/IMC conditions (overcast but thin) and flying the aircraft I am unable to estimate the horizontal range to the traffic accurately. I estimate it was about 1-2 NM at the closest point. A contributing factor was that our air carrier Y was also on frequency. There may have been some confusion, with the controller between air carrier X and air carrier Y.

Original NASA ASRS Text

Title: POTENTIAL CONFLICT IN A NIGHT OP. ALT HDG TRACK DEV.

Narrative: WE WERE FLT (M-88), 20 NM NE OF ATL, BEING VECTORED FOR APCH (ILS 26R) BY ATL APCH. WE WERE AT 8000 FT, 210 KIAS, HDG 230 DEGS. APCH DIRECTED US TO TURN TO A 180 DEG HDG, TO DSND TO 6000 FT AND THEN SLOW TO 180 KIAS. WE WERE THEN GIVEN A FREQ CHANGE. WE WERE UNABLE TO 'CHK IN' IMMEDIATELY DUE TO THE HIGH VOLUME OF COM. AT THIS POINT WE WERE ASKED OUR ASSIGNED HDG BY APCH CTL AND SIMULTANEOUSLY RECEIVED A TCASII TA. THE TCASII SHOWED TFC AT 1 O'CLOCK AND 100 FT LOW. THE RANGE WAS JUST OUTSIDE THE 'MID-SCALE' RING ON THE RADAR SCREEN DISPLAY. I DON'T RECALL IF I WAS IN 5 OR 10 MI SCALE. WE BEGAN TO INITIATE A L TURN, AND WERE DIRECTED BY APCH TO IMMEDIATELY TURN L TO HDG 090 DEGS AND CLB TO 7000 FT. WE DID AS INSTRUCTED AND AFTER THE TURN AND CLB NO FURTHER ACTION WAS TAKEN OR NECESSARY. I DO NOT RECALL RECEIVING A TCASII RA. I DID SEE ACFT LIGHTS AT OUR 1 O'CLOCK POS WHEN INITIATING THE EVASIVE TURN, BUT DUE TO NIGHT/IMC CONDITIONS (OVCST BUT THIN) AND FLYING THE ACFT I AM UNABLE TO ESTIMATE THE HORIZ RANGE TO THE TFC ACCURATELY. I ESTIMATE IT WAS ABOUT 1-2 NM AT THE CLOSEST POINT. A CONTRIBUTING FACTOR WAS THAT OUR ACR Y WAS ALSO ON FREQ. THERE MAY HAVE BEEN SOME CONFUSION, WITH THE CTLR BTWN ACR X AND ACR Y.

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.