B722 crew was reported by ATC as being 8 DME north of course.

Attributes
ACN	511158
Time
Date	200105
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : bkw.vortac
State Reference	WV
Altitude	msl single value : 25000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc.artcc tracon : d01.tracon
Operator	common carrier : air carrier
Make Model Name	B727-200
Operating Under FAR Part	Part 121
Flight Phase	descent : vacating altitude
Route In Use	arrival star : finks
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp pilot : cfi
Experience	flight time last 90 days : 150 flight time total : 24000 flight time type : 9000
ASRS Report	511.158
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : multi engine pilot : commercial
Events
Anomaly	other anomaly other other spatial deviation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance
Supplementary
Problem Areas	Navigational Facility Aircraft
Primary Problem	Navigational Facility
Air Traffic Incident	Pilot Deviation

Narrative:

We were on the finks 6 arrival into dca, descending from FL250 approximately 50-70 DME from bkw VORTAC on the 072 degree radial, when ATC reported that we were 8 DME north of the arrival radial (bkw 072 degree radial). ATC then instructed us to make a right turn to rejoin the 072 degree radial. We initiated the right turn and tuned to the aml VORTAC (on the arrival) to get back on centerline since the bkw radial was unreliable. The bkw VORTAC 072 degree radial and arrival should be checked as to its accuracy and on course guidance. Callback conversation with reporter revealed the following information: reporter stated beckley (bkw) VOR would show on centerline then show a 1:1 and a 1/2 DOT needle swing. The DME was reported as correct and operating properly. This erratic VOR needle swing was unique to the bkw VOR, thereby eliminating aircraft navigation equipment as being the problem. At the time of the incident, ATC was very busy and had little to offer regarding the status of the bkw VOR.

Original NASA ASRS Text

Title: B722 CREW WAS RPTED BY ATC AS BEING 8 DME N OF COURSE.

Narrative: WE WERE ON THE FINKS 6 ARR INTO DCA, DSNDING FROM FL250 APPROX 50-70 DME FROM BKW VORTAC ON THE 072 DEG RADIAL, WHEN ATC RPTED THAT WE WERE 8 DME N OF THE ARR RADIAL (BKW 072 DEG RADIAL). ATC THEN INSTRUCTED US TO MAKE A R TURN TO REJOIN THE 072 DEG RADIAL. WE INITIATED THE R TURN AND TUNED TO THE AML VORTAC (ON THE ARR) TO GET BACK ON CTRLINE SINCE THE BKW RADIAL WAS UNRELIABLE. THE BKW VORTAC 072 DEG RADIAL AND ARR SHOULD BE CHKED AS TO ITS ACCURACY AND ON COURSE GUIDANCE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED BECKLEY (BKW) VOR WOULD SHOW ON CTRLINE THEN SHOW A 1:1 AND A 1/2 DOT NEEDLE SWING. THE DME WAS RPTED AS CORRECT AND OPERATING PROPERLY. THIS ERRATIC VOR NEEDLE SWING WAS UNIQUE TO THE BKW VOR, THEREBY ELIMINATING ACFT NAV EQUIP AS BEING THE PROB. AT THE TIME OF THE INCIDENT, ATC WAS VERY BUSY AND HAD LITTLE TO OFFER REGARDING THE STATUS OF THE BKW VOR.

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.