Narrative:

Having just been turned over to potomac approach control en route from palwaukee airport (chicago), I was instructed to fly direct to a fix and thence cleared for the ILS runway 16L approach at manassas, va. I had been having some radio difficulties on this trip, and I misunderstood the initial approach fix to be cogan rather than the correct colsn. Unable to find it quickly on my charts, I looked it up in a directory I carried, and dialed it into my navigation radio. In as much as the indicated distance to the fix was less than 10 NM, this seemed reasonable and I headed to cogan. Though the heading was away from manassas, it wasn't so far as to be out of the realm of possibility, and I have flown similar, circumspect routes many times before while being vectored on approach. It wasn't until a couple of mins later, when ATC queried my heading and reiterated the colsn fix that I realized that I was headed to the wrong fix. I was able by this time (only 2 or 3 mins later) to locate colsn, but neither the en route low altitude chart or the approach plate for the ILS runway 16L approach show any coordinates for this fix. I asked for and received a heading to fly, and was subsequently vectored to the localizer course, and continued to an uneventful landing at manassas. It is unfortunate that these 2 fixes have similar sounding names, and even more so that ATC would clear an aircraft to a fix that without any published data to allow one to fly direct, no range/radial, or latitude/longitude. Undoubtedly, this is a well used route into the dc area. This is probably a simple oversight that could be easily rectified by publishing the information, in one form or another, on both charts.

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Original NASA ASRS Text

Title: THE SIMILAR SOUNDING COGAN NDB AND THE COLSN RADAR FIX ON THE ILS RWY 16 TO MANASSAS, VA, CAUSE CONFUSION TO A PLT UNFAMILIAR WITH THE AREA LEADING TO A TRACK DEV THAT IS CAUGHT IN A TIMELY FASHION BY POTOMAC APCH.

Narrative: HAVING JUST BEEN TURNED OVER TO POTOMAC APCH CTL ENRTE FROM PALWAUKEE ARPT (CHICAGO), I WAS INSTRUCTED TO FLY DIRECT TO A FIX AND THENCE CLRED FOR THE ILS RWY 16L APCH AT MANASSAS, VA. I HAD BEEN HAVING SOME RADIO DIFFICULTIES ON THIS TRIP, AND I MISUNDERSTOOD THE INITIAL APCH FIX TO BE COGAN RATHER THAN THE CORRECT COLSN. UNABLE TO FIND IT QUICKLY ON MY CHARTS, I LOOKED IT UP IN A DIRECTORY I CARRIED, AND DIALED IT INTO MY NAV RADIO. IN AS MUCH AS THE INDICATED DISTANCE TO THE FIX WAS LESS THAN 10 NM, THIS SEEMED REASONABLE AND I HEADED TO COGAN. THOUGH THE HEADING WAS AWAY FROM MANASSAS, IT WASN'T SO FAR AS TO BE OUT OF THE REALM OF POSSIBILITY, AND I HAVE FLOWN SIMILAR, CIRCUMSPECT ROUTES MANY TIMES BEFORE WHILE BEING VECTORED ON APCH. IT WASN'T UNTIL A COUPLE OF MINS LATER, WHEN ATC QUERIED MY HEADING AND REITERATED THE COLSN FIX THAT I REALIZED THAT I WAS HEADED TO THE WRONG FIX. I WAS ABLE BY THIS TIME (ONLY 2 OR 3 MINS LATER) TO LOCATE COLSN, BUT NEITHER THE ENRTE LOW ALT CHART OR THE APCH PLATE FOR THE ILS RWY 16L APCH SHOW ANY COORDINATES FOR THIS FIX. I ASKED FOR AND RECEIVED A HEADING TO FLY, AND WAS SUBSEQUENTLY VECTORED TO THE LOC COURSE, AND CONTINUED TO AN UNEVENTFUL LNDG AT MANASSAS. IT IS UNFORTUNATE THAT THESE 2 FIXES HAVE SIMILAR SOUNDING NAMES, AND EVEN MORE SO THAT ATC WOULD CLR AN ACFT TO A FIX THAT WITHOUT ANY PUBLISHED DATA TO ALLOW ONE TO FLY DIRECT, NO RANGE/RADIAL, OR LATITUDE/LONGITUDE. UNDOUBTEDLY, THIS IS A WELL USED RTE INTO THE DC AREA. THIS IS PROBABLY A SIMPLE OVERSIGHT THAT COULD BE EASILY RECTIFIED BY PUBLISHING THE INFO, IN ONE FORM OR ANOTHER, ON BOTH CHARTS.

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.