Widebody transport aircraft on approach goes through a heading track deviation.

Attributes
ACN	186744
Time
Date	199108
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : atl
State Reference	GA
Altitude	msl bound lower : 3500 msl bound upper : 3500
Environment
Flight Conditions	VMC
Light	Daylight
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 : captain oversight : pic
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 152 flight time total : 16123 flight time type : 2150
ASRS Report	186744
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe non adherence : clearance non adherence : published procedure other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : overcame equipment problem flight crew : became reoriented flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While landing at the hartsfield international airport the following occurred: the first officer was flying and initially navigating by the LNAV on the atl 27L localizer course at 3500 ft MSL. The first officer armed the localizer button on the mode control panel and the aircraft abruptly turned to the left. The first officer disengaged the autoplt and manually corrected back to course. The localizer needle moved back and forth. Approach control issued heading changes, a clearance to 2800 ft MSL, a radio frequency change to tower, and an altitude alert. Altitude was checked and appeared acceptable. No cockpit altitude warning received. While analyzing the problem and considering a missed approach, we saw the first number in the ILS course window to be numeral 1. The remaining numbers were 72. The correct inbound course is 272. This was corrected and localizer indications appeared normal. The ILS radio receiver is an electro-mechanical unit. The company has acknowledged previous problems with this unit. A normal landing was made. All company checklists and procedures were complied with.

Original NASA ASRS Text

Title: WDB ACFT ON APCH GOES THROUGH A HDG TRACK DEV.

Narrative: WHILE LNDG AT THE HARTSFIELD INTL ARPT THE FOLLOWING OCCURRED: THE FO WAS FLYING AND INITIALLY NAVING BY THE LNAV ON THE ATL 27L LOC COURSE AT 3500 FT MSL. THE FO ARMED THE LOC BUTTON ON THE MODE CTL PANEL AND THE ACFT ABRUPTLY TURNED TO THE L. THE FO DISENGAGED THE AUTOPLT AND MANUALLY CORRECTED BACK TO COURSE. THE LOC NEEDLE MOVED BACK AND FORTH. APCH CTL ISSUED HDG CHANGES, A CLRNC TO 2800 FT MSL, A RADIO FREQ CHANGE TO TWR, AND AN ALT ALERT. ALT WAS CHKED AND APPEARED ACCEPTABLE. NO COCKPIT ALT WARNING RECEIVED. WHILE ANALYZING THE PROBLEM AND CONSIDERING A MISSED APCH, WE SAW THE FIRST NUMBER IN THE ILS COURSE WINDOW TO BE NUMERAL 1. THE REMAINING NUMBERS WERE 72. THE CORRECT INBOUND COURSE IS 272. THIS WAS CORRECTED AND LOC INDICATIONS APPEARED NORMAL. THE ILS RADIO RECEIVER IS AN ELECTRO-MECHANICAL UNIT. THE COMPANY HAS ACKNOWLEDGED PREVIOUS PROBLEMS WITH THIS UNIT. A NORMAL LNDG WAS MADE. ALL COMPANY CHKLISTS AND PROCS WERE COMPLIED WITH.

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.