Captain of air carrier light transport aircraft complaint of an unreliable VORTAC NAVAID.

Attributes
ACN	236539
Time
Date	199303
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ghm
State Reference	TN
Altitude	msl bound lower : 10000 msl bound upper : 10000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : lan
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Flight Phase	cruise other descent other
Route In Use	enroute airway : zme
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : instrument
Experience	flight time last 90 days : 270 flight time total : 11000 flight time type : 4600
ASRS Report	236539
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Navigational Facility
Air Traffic Incident	other
Situations
Navigational Aid	Unspecified

Narrative:

Our airline started service to nashville, tn, recently and I have noticed during my 6 flts into bna that the graham VOR, 40 NM west of bna, has big azimuth fluctuations. That VOR needle swings so badly, that you have to take the autoplt off the 'navigation' mode and apply 'heading' mode (leaving it on 'navigation' will get you rolling back and forth). I advised center control about it and he responded with 'you're the 1ST one to complain about graham VOR!' (maybe nobody wants to say anything.) we were cruising at FL250, heading 095 degrees direct graham VOR for graham 3 arrival into bna. Descending through 10000 ft and within 20 NM of the VOR the deviations seemed to get worse. At the breakfast table 30 mins later, inside the bna terminal, I asked 2 other capts about graham VOR and they had the same experiences as I had during their arrs ever since we started bna service a month ago.

Original NASA ASRS Text

Title: CAPT OF ACR LTT ACFT COMPLAINT OF AN UNRELIABLE VORTAC NAVAID.

Narrative: OUR AIRLINE STARTED SVC TO NASHVILLE, TN, RECENTLY AND I HAVE NOTICED DURING MY 6 FLTS INTO BNA THAT THE GRAHAM VOR, 40 NM W OF BNA, HAS BIG AZIMUTH FLUCTUATIONS. THAT VOR NEEDLE SWINGS SO BADLY, THAT YOU HAVE TO TAKE THE AUTOPLT OFF THE 'NAV' MODE AND APPLY 'HDG' MODE (LEAVING IT ON 'NAV' WILL GET YOU ROLLING BACK AND FORTH). I ADVISED CTR CTL ABOUT IT AND HE RESPONDED WITH 'YOU'RE THE 1ST ONE TO COMPLAIN ABOUT GRAHAM VOR!' (MAYBE NOBODY WANTS TO SAY ANYTHING.) WE WERE CRUISING AT FL250, HDG 095 DEGS DIRECT GRAHAM VOR FOR GRAHAM 3 ARR INTO BNA. DSNDING THROUGH 10000 FT AND WITHIN 20 NM OF THE VOR THE DEVS SEEMED TO GET WORSE. AT THE BREAKFAST TABLE 30 MINS LATER, INSIDE THE BNA TERMINAL, I ASKED 2 OTHER CAPTS ABOUT GRAHAM VOR AND THEY HAD THE SAME EXPERIENCES AS I HAD DURING THEIR ARRS EVER SINCE WE STARTED BNA SVC A MONTH AGO.

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.