Air carrier widebody transport track heading deviation making a coupled approach to atl.

Attributes
ACN	186479
Time
Date	199108
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : atl
State Reference	GA
Altitude	msl bound lower : 2800 msl bound upper : 3500
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	tracon : atl
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : commercial
Experience	flight time last 90 days : 150 flight time total : 3000 flight time type : 200
ASRS Report	186479
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We received a turn to intercept the localizer for runway 27L atlanta. We were at 3500 ft MSL 20 NM from airport. LNAV was used to track runway centerline inbound due to fluctuating localizer 20 mi from the runway. When localizer was selected on the mode control panel the aircraft banked left. Since this was an incorrect turn based on where we were, I disengaged the autoplt and initiated a turn to the right to reintercept the localizer. It was then I noticed that 172 degree was set in the heading select window not 272 degree which is the correct setting. We received a descent to 2800 ft and a switch frequency to tower all in the vicinity of the OM. When we reset the heading window to 272 degree, proper ILS information was received and a landing was made without incident. The question remains as to how 172 degree instead of 272 degree was set into the heading select window. The numbers are manually set and electromagnetically rotated inside the ILS select panel. When the approach was briefed (about 17000 ft MSL in the descent) the captain set 108.5 frequency and 272 degree heading, I crosschecked these numbers and was satisfied that these were correct. How 172 degree arrived in the window is still in question in my mind.

Original NASA ASRS Text

Title: ACR WDB TRACK HDG DEV MAKING A COUPLED APCH TO ATL.

Narrative: WE RECEIVED A TURN TO INTERCEPT THE LOC FOR RWY 27L ATLANTA. WE WERE AT 3500 FT MSL 20 NM FROM ARPT. LNAV WAS USED TO TRACK RWY CENTERLINE INBOUND DUE TO FLUCTUATING LOC 20 MI FROM THE RWY. WHEN LOC WAS SELECTED ON THE MODE CTL PANEL THE ACFT BANKED L. SINCE THIS WAS AN INCORRECT TURN BASED ON WHERE WE WERE, I DISENGAGED THE AUTOPLT AND INITIATED A TURN TO THE R TO REINTERCEPT THE LOC. IT WAS THEN I NOTICED THAT 172 DEG WAS SET IN THE HDG SELECT WINDOW NOT 272 DEG WHICH IS THE CORRECT SETTING. WE RECEIVED A DSCNT TO 2800 FT AND A SWITCH FREQ TO TWR ALL IN THE VICINITY OF THE OM. WHEN WE RESET THE HDG WINDOW TO 272 DEG, PROPER ILS INFO WAS RECEIVED AND A LNDG WAS MADE WITHOUT INCIDENT. THE QUESTION REMAINS AS TO HOW 172 DEG INSTEAD OF 272 DEG WAS SET INTO THE HDG SELECT WINDOW. THE NUMBERS ARE MANUALLY SET AND ELECTROMAGNETICALLY ROTATED INSIDE THE ILS SELECT PANEL. WHEN THE APCH WAS BRIEFED (ABOUT 17000 FT MSL IN THE DSCNT) THE CAPT SET 108.5 FREQ AND 272 DEG HDG, I XCHKED THESE NUMBERS AND WAS SATISFIED THAT THESE WERE CORRECT. HOW 172 DEG ARRIVED IN THE WINDOW IS STILL IN QUESTION IN MY MIND.

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.