Narrative:

The WX at meigs was obscured 3 mi in fog and below the published visibility approach minimums. We proceeded to shoot the ILS 30 approach at gary, in and proceed to meigs VFR. The gary WX was obscured 2 mi fog. We shot the ILS to 2000' MSL, cancelled the IFR and proceeded out of the gary control zone on a SVFR. Upon reaching the northwest limit of the zone, we advised gary we were clear and the tower acknowledged. The PF proceeded to the shoreline on an approximately heading of 315 degrees in VFR conditions with fog obscuring most of the surface. Direct to meigs field was selected on our navigation system and we advised meigs tower of our position. Heading and distance appeared correct for direct to meigs; however, the navigation system failed and went into dead reckoning mode shortly after direct to meigs was selected. We noticed an aircraft, approximately 3-5 mi ahead and 1000' above, pass in front of us. I reinitiated our navigation system and it showed meigs 36 degrees and 7 mi. We proceeded direct, again, and passed to the south of meigs for a left downwind to runway 18. We were cleared to land and after landing told to call mdw tower. Mdw tower said we had penetrated their arsa and were in close proximity of a departure aircraft. I explained what had happened to the controller and he seemed satisfied with the explanation. I realize it's totally our responsibility to now our position at all times and it's too bad our navigation system decided to fail at such a crucial time. It would be nice, however, to have a more practical published visibility approach into meigs that didn't require 6 mi visibility to use.

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Original NASA ASRS Text

Title: CPR LTT UNAUTH PENETRATION OF AIRSPACE.

Narrative: THE WX AT MEIGS WAS OBSCURED 3 MI IN FOG AND BELOW THE PUBLISHED VIS APCH MINIMUMS. WE PROCEEDED TO SHOOT THE ILS 30 APCH AT GARY, IN AND PROCEED TO MEIGS VFR. THE GARY WX WAS OBSCURED 2 MI FOG. WE SHOT THE ILS TO 2000' MSL, CANCELLED THE IFR AND PROCEEDED OUT OF THE GARY CTL ZONE ON A SVFR. UPON REACHING THE NW LIMIT OF THE ZONE, WE ADVISED GARY WE WERE CLR AND THE TWR ACKNOWLEDGED. THE PF PROCEEDED TO THE SHORELINE ON AN APPROX HDG OF 315 DEGS IN VFR CONDITIONS WITH FOG OBSCURING MOST OF THE SURFACE. DIRECT TO MEIGS FIELD WAS SELECTED ON OUR NAV SYS AND WE ADVISED MEIGS TWR OF OUR POS. HDG AND DISTANCE APPEARED CORRECT FOR DIRECT TO MEIGS; HOWEVER, THE NAV SYS FAILED AND WENT INTO DEAD RECKONING MODE SHORTLY AFTER DIRECT TO MEIGS WAS SELECTED. WE NOTICED AN ACFT, APPROX 3-5 MI AHEAD AND 1000' ABOVE, PASS IN FRONT OF US. I REINITIATED OUR NAV SYS AND IT SHOWED MEIGS 36 DEGS AND 7 MI. WE PROCEEDED DIRECT, AGAIN, AND PASSED TO THE S OF MEIGS FOR A LEFT DOWNWIND TO RWY 18. WE WERE CLRED TO LAND AND AFTER LNDG TOLD TO CALL MDW TWR. MDW TWR SAID WE HAD PENETRATED THEIR ARSA AND WERE IN CLOSE PROX OF A DEP ACFT. I EXPLAINED WHAT HAD HAPPENED TO THE CTLR AND HE SEEMED SATISFIED WITH THE EXPLANATION. I REALIZE IT'S TOTALLY OUR RESPONSIBILITY TO NOW OUR POS AT ALL TIMES AND IT'S TOO BAD OUR NAV SYS DECIDED TO FAIL AT SUCH A CRUCIAL TIME. IT WOULD BE NICE, HOWEVER, TO HAVE A MORE PRACTICAL PUBLISHED VIS APCH INTO MEIGS THAT DIDN'T REQUIRE 6 MI VISIBILITY TO USE.

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.