A GOV HELI PLT VIOLATED THE DC ADIZ.

Narrative

I WAS XPORTING A HELI FROM OUR OFFICE TO HICKORY; NC. I PLANNED A STOP AT BWI TO REFUEL MY HELI. AT APPROX 18 DME N OF BWI; I HEARD OVER 121.5 'ACFT X 4 NM N OF BALTIMORE XX HDG AT 1400 FT; SUGGEST YOU TURN N. YOU ARE 2 MI; END OF XMISSION. THE XMISSION WAS NOT CLR. I HAD PREVIOUSLY ATTEMPTED TO CONTACT POTOMAC APCH ON 119.7 WITHOUT SUCCESS. UPON HEARING THIS XMISSION; AND NOT BEING IN RADIO CONTACT; I TURNED AROUND AND PROCEEDED TO MY PLANNED ALTERNATE REFUELING LOCATION. I WAS FINALLY ABLE TO CONTACT POTOMAC APCH ENRTE TO MY ALTERNATE. I HAD TO CLB TO 2500 FT TO ESTABLISH RADIO CONTACT AND FLT FOLLOWING. ENRTE; POTOMAC APCH ADVISED ME TO CALL THEM. WHEN I LANDED; I CALLED THE NUMBER AND GAVE THEM MY INFO. I ALSO ADVISED THEM THAT I WAS A GOV PLT XPORTING AN ACFT FROM THE NEW YORK AREA TO HICKORY; NC. CONTRIBUTING FACTORS THAT LEAD TO ATC CALLING ME WERE THAT I WAS UNABLE TO REACH THEM ON THE RADIO. I HAD MY LOCATION 18 DME OUT OF BWI; AND I THOUGHT I HAD A FEW MORE MI BEFORE I ENTERED THE SAFETY AREA. I HAVE BEEN TO THE WASHINGTON AREA SEVERAL TIMES ON IFR FLTS SINCE THE INSTITUTION OF THE SFAR; BUT NOT VFR. I REVIEWED NOTAMS AND TFR'S PRIOR TO DEPARTING; AND BELIEVED I HAD A GOOD UNDERSTANDING OF THE REQUIREMENTS. I WOULD SUGGEST THAT ANYONE WHO INTENDS TO OPERATE IN THE BWI AREA FIRST FLY IN THAT AREA WITH SOMEONE WHO IS EXPERIENCED WITH THE SPECIAL AIRSPACE CONCERNS OF THE CAPITOL.