FLT INSTRUCTOR AND PRIVATE PLT OF PA28 ARE CONCERNED THEY MAY HAVE ENTERED THE DC ADIZ WHILE PERFORMING THE PUBLISHED MAP FOR THE GPS-Z RWY 23 IAP AT FDK.

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AFTER SUCCESSFULLY FLYING THE GPS Z RWY 23 APCH AT FREDERICK; MD (FDK) WITH WAAS GUIDANCE; EXECUTED THE PUBLISHED MISSED APCH. THE PIC WAS A CFI CONDUCTING A CHKOUT IN THE ARROW FOR THE PF; WHO IS THE RPTING PARTY. THE NIGHT WAS CLR; WITH UNRESTR VISIBILITY. WE HAD EXITED THE WASHINGTON DC ADIZ SHORTLY BEFORE THIS TIME; WITH THE INTENTION OF FLYING 2 WAAS APCHS INTO FREDERICK PRIOR TO RETURN TO TIPTON AIRFIELD IN FORT MEADE; MD (FME). THE FIRST PHASE OF THE MISSED APCH INVOLVES A STRAIGHT CLB TO 3000 FT MSL; FOLLOWED BY A TURN TO THE E AT THE FIRST MISSED APCH WAYPOINT. THIS TURN WAS ACCOMPLISHED; AND THE ACFT PROCEEDED TO THE SECOND TURN; WHICH CALLS FOR A TURN TO 059 DEGS BACK TO THE MISSED APCH HOLD AT WESTMINSTER (EMI). THE PF EXECUTED A FLY-BY TURN TO THE NEW HDG SHORT OF THE PUBLISHED WAYPOINT. THESE TURNS WERE EXECUTED USING THE INSTALLED GARMIN 430 GPS SYS. SHORTLY AFTER ROLLING OUT ON THE 059 DEG HDG; THE CREW HEARD THE FOLLOWING MESSAGE ON 121.5: 'ACFT 9 MI E OF FREDERICK ON HDG 065 DEGS AT 2500 FT INDICATED; YOU HAVE ENTERED AN AIR DEFENSE IDENT ZONE; SHORTEST RTE TO EXIT IS (WESTERLY HDG) AT 1 MI.' IT WAS NOT CLR TO THE CREW THAT THIS XMISSION WAS INTENDED FOR US; HOWEVER; THE LOCATION; ALT AND COURSE GIVEN WERE SUFFICIENTLY CLOSE TO CAUSE CONCERN. THE PF DEVIATED W OF COURSE (AWAY FROM THE ADIZ); AND ABOUT 5 MINS LATER ENTERED A DIRECT TO EMI COURSE; PROCEEDED TO EMI; AND SUBSEQUENTLY COMPLETED THE FLT BY FLYING THE GPS RWY 16 APCH TO CARROLL COUNTY ARPT (DMW); WITH A LNDG TO A FULL STOP; FOLLOWED BY A RETURN TO TIPTON (FME) VIA A PREVIOUSLY FILED ADIZ FLT PLAN. THE REMAINDER OF THE FLT PROCEEDED WITHOUT INCIDENT. THERE WERE NO FURTHER COMS ON 121.5. UPON RETURN TO FME; THE CREW RECONSTRUCTED THE PRESUMED FLT PATH OF THE ACFT TO THE EXTENT POSSIBLE; BY OVERLAYING THE PUBLISHED MISSED APCH VECTORS ON THE WASHINGTON TERMINAL CHART. ALTHOUGH IT IS HARD TO DETERMINE WITH COMPLETE ACCURACY; IT APPEARS THAT PORTIONS OF THE THIRD LEG OF THE MISSED APCH PROC; DO IN FACT LIE INSIDE THE ADIZ. THE ACFT IS EQUIPPED WITH DME; BUT IT WAS NOT IN USE; AND IN ANY EVENT THE RELIABILITY OF THE DCA VORTAC SIGNAL AT LOW ALT AND 30 MI AWAY IS SPOTTY. THE CREW WAS UNABLE TO USE THE GARMIN 430 FOR DISTANCE MEASURING FROM DCA BECAUSE THE UNIT WAS IN USE FOR THE MISSED APCH PROC. LANDMARKS; AS VISIBLE DURING NIGHTTIME IN THIS AREA; WERE NOT INCONSISTENT WITH A POS NEAR TO; BUT OUTSIDE THE ADIZ. THE PRIMARY CAUSE FOR THIS INADVERTENT ENTRY INTO THE ADIZ WAS THE ASSUMPTION ON THE PART OF THE CREW (A POOR ONE) THAT NO PUBLISHED PROC WOULD LEAD THE ACFT DIRECTLY INTO THE ADIZ. OTHER PROCS; NOTABLY FOR MULTIPLE APCHS AT CARROLL COUNTY; SHOW THE RELATIVE POS OF THE ADIZ ON THE APCH CHART ITSELF. THIS CHART HAS NO SUCH INFO; NOR DOES IT CONTAIN ANY NOTIFICATION REGARDING THE OVERLAP IN AIRSPACE; OR WARNING REGARDING THE APPROPRIATE CIRCUMSTANCES FOR USE. NOR IS THE LOCATION OF THE 2 KEY MISSED APCH WAYPOINTS EASILY DETERMINED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STRESSED THAT THEY WERE FLYING THE GPS-Z IAP WHICH REQUIRES A GPS EQUIPPED WITH WAAS CAPABILITY. UNLIKE THE GPS-Z MISSED APPROACH; THE MAP FOR THE GPS-Y PROCEDURE FOR NON WAAS EQUIPPED ACFT EMPLOYS AN INITIAL TRACK WHICH IS A 160 OR SO DEGREE LEFT TURN DIRECT TO EMI; WHICH AVOIDS THE DC ADIZ BY A WIDE MARGIN. IN ADDITION; IT IS ONLY AS A RESULT OF THE COMPARATIVELY RECENT ALTERATION TO THE DC ADIZ CONFIGURATION THAT FEDIT WAYPOINT FALLS WITHIN THE ADIZ. ALTHOUGH BOTH PILOTS IN THIS REPORT ARE INVOLVED WITH ADIZ MANAGEMENT THEY FAILED TO RECOGNIZE THE IMPACT OF THE CHANGE ON THEIR OPERATION.