Narrative:

While flying from phoenix deer valley to yuma, I intercepted the gbn 247 degree radial approximately 33 mi from gbn. As I approached mohak intersection with the CDI centered (gbn 247 degree radial), I started a VFR descent and contacted yuma approach with ATIS information. The controller informed me I was 3 mi into a restr airspace, and to immediately correct with a left turn. I did this and then was told I was crossing out of the restr airspace about 1 min later. I couldn't believe this was happening -- as the CDI was centered on gbn 247 degrees. I then switched to bza 075 degree radial inbound 255 degrees and saw the CDI move just about full scale left -- indicating to me that indeed I was north of course. On further inspection it has been determined that while a vot check was done on jun/xa/99, and well within limits -- the VOR was indeed malfunctioning with an error of up to 8 degrees. Maintenance has been apprised of this malfunction and has taken steps to correct the navigation receiver. While having flown for 32 yrs, I have never seen such an error in a VOR. In the future all VOR usage will be backed up by GPS. It is imperative to note this was neither intentional, nor deliberate, as I have never had a violation of FARS in 32 yrs of professional flying.

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Original NASA ASRS Text

Title: PLT OF AN CPR SMT TWIN INADVERTENTLY ENTERED RESTR AIRSPACE DUE TO AN ERROR IN HIS VOR NAV RECEIVER. HE WAS NOT ON A FLT PLAN.

Narrative: WHILE FLYING FROM PHOENIX DEER VALLEY TO YUMA, I INTERCEPTED THE GBN 247 DEG RADIAL APPROX 33 MI FROM GBN. AS I APCHED MOHAK INTXN WITH THE CDI CTRED (GBN 247 DEG RADIAL), I STARTED A VFR DSCNT AND CONTACTED YUMA APCH WITH ATIS INFO. THE CTLR INFORMED ME I WAS 3 MI INTO A RESTR AIRSPACE, AND TO IMMEDIATELY CORRECT WITH A L TURN. I DID THIS AND THEN WAS TOLD I WAS XING OUT OF THE RESTR AIRSPACE ABOUT 1 MIN LATER. I COULDN'T BELIEVE THIS WAS HAPPENING -- AS THE CDI WAS CTRED ON GBN 247 DEGS. I THEN SWITCHED TO BZA 075 DEG RADIAL INBOUND 255 DEGS AND SAW THE CDI MOVE JUST ABOUT FULL SCALE L -- INDICATING TO ME THAT INDEED I WAS N OF COURSE. ON FURTHER INSPECTION IT HAS BEEN DETERMINED THAT WHILE A VOT CHK WAS DONE ON JUN/XA/99, AND WELL WITHIN LIMITS -- THE VOR WAS INDEED MALFUNCTIONING WITH AN ERROR OF UP TO 8 DEGS. MAINT HAS BEEN APPRISED OF THIS MALFUNCTION AND HAS TAKEN STEPS TO CORRECT THE NAV RECEIVER. WHILE HAVING FLOWN FOR 32 YRS, I HAVE NEVER SEEN SUCH AN ERROR IN A VOR. IN THE FUTURE ALL VOR USAGE WILL BE BACKED UP BY GPS. IT IS IMPERATIVE TO NOTE THIS WAS NEITHER INTENTIONAL, NOR DELIBERATE, AS I HAVE NEVER HAD A VIOLATION OF FARS IN 32 YRS OF PROFESSIONAL FLYING.

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.