Heading track deviation produces a potential conflict between 2 air carrier aircraft on approach pro...

Attributes
ACN	242584
Time
Date	199305
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : atl
State Reference	GA
Altitude	msl bound lower : 3700 msl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	tracon : atl
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent : approach
Route In Use	approach : straight in
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : atp pilot : instrument
Experience	flight time last 90 days : 180 flight time total : 13550 flight time type : 2800
ASRS Report	242584
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation non adherence : clearance other spatial deviation
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa
Resolutory Action	flight crew : took evasive action flight crew : became reoriented other
Consequence	Other
Miss Distance	vertical : 300
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

The copilot was flying the aircraft and we were cleared the visual approach to runway 26R atl and told to keep the large transport that was 3 mi ahead in sight. At about 4500 ft on glide path on localizer, I, the captain, asked approach control about a widebody transport below and slightly behind us to the left. He responded, 'he is going to another runway.' at this time, I felt approach control knew better than I his position, so I shifted my attention back to the landing. I again checked his position at about 4000 ft and he seemed much closer. As I watched him, he was moving in our direction, so I told the copilot to level off. At this time, approach control instructed us to stop descent, saying the widebody transport had overshot the localizer for runway 27L. Also at this time, the TCASII went off. I could see he was correcting so I asked to resume the approach.

Original NASA ASRS Text

Title: HDG TRACK DEV PRODUCES A POTENTIAL CONFLICT BTWN 2 ACR ACFT ON APCH PROC.

Narrative: THE COPLT WAS FLYING THE ACFT AND WE WERE CLRED THE VISUAL APCH TO RWY 26R ATL AND TOLD TO KEEP THE LGT THAT WAS 3 MI AHEAD IN SIGHT. AT ABOUT 4500 FT ON GLIDE PATH ON LOC, I, THE CAPT, ASKED APCH CTL ABOUT A WDB BELOW AND SLIGHTLY BEHIND US TO THE L. HE RESPONDED, 'HE IS GOING TO ANOTHER RWY.' AT THIS TIME, I FELT APCH CTL KNEW BETTER THAN I HIS POS, SO I SHIFTED MY ATTN BACK TO THE LNDG. I AGAIN CHKED HIS POS AT ABOUT 4000 FT AND HE SEEMED MUCH CLOSER. AS I WATCHED HIM, HE WAS MOVING IN OUR DIRECTION, SO I TOLD THE COPLT TO LEVEL OFF. AT THIS TIME, APCH CTL INSTRUCTED US TO STOP DSCNT, SAYING THE WDB HAD OVERSHOT THE LOC FOR RWY 27L. ALSO AT THIS TIME, THE TCASII WENT OFF. I COULD SEE HE WAS CORRECTING SO I ASKED TO RESUME THE APCH.

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.

Heading track deviation produces a potential conflict between 2 air carrier aircraft on approach procedure.