Air carrier crew finds themselves outside holding space when xchking backup navaids.

Attributes
ACN	446690
Time
Date	199908
Day	Fri
Local Time Of Day	1201 To 1800
Place
State Reference	SC
Altitude	msl single value : 33000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx.artcc
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other other vortac
Flight Phase	cruise : holding
Route In Use	arrival : holding pattern
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain
Qualification	pilot : atp pilot : multi engine pilot : instrument pilot : cfi pilot : commercial
Experience	flight time last 90 days : 206 flight time total : 19126 flight time type : 2299
ASRS Report	446690
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : less severe non adherence : clearance other spatial deviation
Independent Detector	aircraft equipment other aircraft equipment : number 2 vor / fms other flight crewa
Resolutory Action	flight crew : returned to original clearance
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Cleared to hold at casat intersection. I elected to use the #1 VOR for the most reliable information. As we intercepted the inbound radial, I realized that there was a discrepancy between the #1 and #2 vors. We were off course. I decided that the #1 VOR had malfunctioned after xchking the information from all other sources. The controller never said anything, and upon landing, we wrote up the discrepancy. Always xchk your navigation information with all available sources.

Original NASA ASRS Text

Title: ACR CREW FINDS THEMSELVES OUTSIDE HOLDING SPACE WHEN XCHKING BACKUP NAVAIDS.

Narrative: CLRED TO HOLD AT CASAT INTXN. I ELECTED TO USE THE #1 VOR FOR THE MOST RELIABLE INFO. AS WE INTERCEPTED THE INBOUND RADIAL, I REALIZED THAT THERE WAS A DISCREPANCY BTWN THE #1 AND #2 VORS. WE WERE OFF COURSE. I DECIDED THAT THE #1 VOR HAD MALFUNCTIONED AFTER XCHKING THE INFO FROM ALL OTHER SOURCES. THE CTLR NEVER SAID ANYTHING, AND UPON LNDG, WE WROTE UP THE DISCREPANCY. ALWAYS XCHK YOUR NAV INFO WITH ALL AVAILABLE SOURCES.

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.