Narrative:

This is my third report for this exact event. Between eno and skipy on the korry 3; ZDC asked if we were using FMS navigation. We responded affirmative and they reported that we were about 1 mi west of course paralleling the course. Magenta and green needles were both centered and LNAV was engaged using the FMS. I went to the 'FMS navigation:sensors:GPS position' page and noticed that the airplane was .7 mi west of the GPS position. I will keep submitting this same report every time this happens until I get an explanation of why this continues to occur. There is no action that we could have taken to prevent this type of deviation.

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Original NASA ASRS Text

Title: EMB135 CREW RPTS CONCERNS WITH NAV ACCURACY DURING KORRY 3 STAR.

Narrative: THIS IS MY THIRD RPT FOR THIS EXACT EVENT. BTWN ENO AND SKIPY ON THE KORRY 3; ZDC ASKED IF WE WERE USING FMS NAV. WE RESPONDED AFFIRMATIVE AND THEY RPTED THAT WE WERE ABOUT 1 MI W OF COURSE PARALLELING THE COURSE. MAGENTA AND GREEN NEEDLES WERE BOTH CTRED AND LNAV WAS ENGAGED USING THE FMS. I WENT TO THE 'FMS NAV:SENSORS:GPS POS' PAGE AND NOTICED THAT THE AIRPLANE WAS .7 MI W OF THE GPS POS. I WILL KEEP SUBMITTING THIS SAME RPT EVERY TIME THIS HAPPENS UNTIL I GET AN EXPLANATION OF WHY THIS CONTINUES TO OCCUR. THERE IS NO ACTION THAT WE COULD HAVE TAKEN TO PREVENT THIS TYPE OF DEV.

Data retrieved from NASA's ASRS site as of January 2009 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.