Air carrier small transport track deviation caused by faulty navigation equipment.

Attributes
ACN	102018
Time
Date	198901
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : rdu
State Reference	NC
Altitude	msl bound lower : 1800 msl bound upper : 2200
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : rdu
Operator	common carrier : air carrier
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Flight Phase	descent : approach
Route In Use	approach : straight in
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 3000 flight time type : 1000
ASRS Report	102018
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : cfi pilot : commercial
Experience	flight time last 90 days : 90 flight time total : 1900 flight time type : 890
ASRS Report	102130
Events
Anomaly	aircraft equipment problem : critical other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation other

Narrative:

Departed phf for rdu at XA40. The flight proceeded smoothly. The flight was cleared for an ILS 23L approach at rdu. Just outside the OM the localizer course began deviating left and right of course. All 3 navigation radios were tuned and idented to 108.50, the localizer frequency. All localizer needles would more together as if they were synchronized. As we broke out of the clouds we found ourselves between runways 23L and 23R. ATC advised no sep rules were violated. Investigation into the aircraft revealed this to be the third known incident involving aircraft with localizer problems in the last 2 weeks.

Original NASA ASRS Text

Title: ACR SMT TRACK DEVIATION CAUSED BY FAULTY NAVIGATION EQUIPMENT.

Narrative: DEPARTED PHF FOR RDU AT XA40. THE FLT PROCEEDED SMOOTHLY. THE FLT WAS CLRED FOR AN ILS 23L APCH AT RDU. JUST OUTSIDE THE OM THE LOC COURSE BEGAN DEVIATING LEFT AND RIGHT OF COURSE. ALL 3 NAV RADIOS WERE TUNED AND IDENTED TO 108.50, THE LOC FREQ. ALL LOC NEEDLES WOULD MORE TOGETHER AS IF THEY WERE SYNCHRONIZED. AS WE BROKE OUT OF THE CLOUDS WE FOUND OURSELVES BTWN RWYS 23L AND 23R. ATC ADVISED NO SEP RULES WERE VIOLATED. INVESTIGATION INTO THE ACFT REVEALED THIS TO BE THE THIRD KNOWN INCIDENT INVOLVING ACFT WITH LOC PROBS IN THE LAST 2 WKS.

Data retrieved from NASA's ASRS site as of August 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.