SMT ENTERS TCA WITHOUT CONTACT.

Narrative

OUR FLT ACTIVITIES WERE TO TAKE CARGO IN AN SMT FROM TTN TO 06G. I WAS A FLT INSTRUCTOR WHO WAS IN TRAINING FOR AN UPGRADE TO SIC IN THE SMT SO I WENT ALONG AS CARGO HANDLER; AND THE CAPT OF THE FLT WAS AN EXPERIENCED PART 135 INSTRUCTOR PLT. AFTER ARRIVING AT 06G AND DELIVERING OUR FREIGHT; WE REPOSITIONED TO YNG TO GET A BRIEFING. WE HAD AN EMPTY LEG BACK TO BED (BEDFORD; MA) WHERE WE WOULD PICK UP MORE FREIGHT. WE RECEIVED A COMPLETE BRIEFING IN PERSON FROM THE YNG FSS; THEN DEPARTED BECAUSE I WAS IN TRAINING; I WAS ALLOWED TO FLY THIS LEG; AND THE CAPT WAS PERFORMING ALL SIC DUTIES (RADIOS; NAV; ETC). AS WE NEARED BED; WE WERE STILL TRACKING OUTBOUND FROM DELANCEY VOR; BUT WE WERE NO LONGER RECEIVING DME INDICATIONS DUE TO OUR DISTANCE. THE CAPT INSTRUCTED ME WHAT RADIAL TO FLY; AND WE SET BOS VOR IN OUR #2 NAV; AND SET THE DME TO #2. BEDFORD HAS NO VOR ON THE FIELD; SO WE SET THE LOCATOR-OM (BEDDS) TO OUR ADF. AS THE LOM BEGAN TO PROVIDE A GOOD SIGNAL; WE BEGAN TRACKING TOWARDS IT AND DSNDING. WE WERE STILL WAITING FOR BOS DME TO APPEAR; FEELING THIS WOULD GIVE ADEQUATE WARNING PRIOR TO THE TCA BORDER. WE BOTH THOUGHT WE WERE STILL ABOUT 30 NM FROM BEDFORD; AND WERE EXPECTING TO SEE THE DME ANY SECOND. AS I WAS WATCHING OUTSIDE; DSNDING THROUGH 4300; I WAS SURPRISED TO SEE AN ARPT AT MY 1-2 O'CLOCK; THEN I QUICKLY REALIZED THAT IT WAS BED. WE WERE STILL TRACKING TO THE LOM; REALIZING THAT WE MUST BE EITHER VERY CLOSE OR EVEN IN BOS TCA; I MADE A TURN TO A WBOUND HDG AND BEGAN A DSCNT. WE KNOW WE WERE STILL TO THE W OF BEDDS WHEN WE TURNED WBOUND; BUT THE TCA BORDER IS ABOUT 1 NM W OF BEDDS. WHETHER WE VIOLATED THE TCA OR NOT; THE INCIDENT SHOOK BOTH OF US TO THE IMPORTANCE OF CONSTANTLY KNOWING EXACTLY WHERE YOU ARE. ALSO; THERE ARE BETTER WAYS TO KNOW HOW FAR YOU ARE THAN JUST USING DME AND WAITING FOR A SIGNAL. WE SHOULD HAVE HAD CROSS RADIALS SET TO DETERMINE OUR LOCATION; AND BEING A FAST AIRPLANE; WE ALSO SHOULD HAVE BEEN TALKING TO BOS APCH. LATER; AFTER LNDG; WE CHKED WITH FSS; AND LEARNED THAT BOS DME HAD BEEN NOTAMED OTS AT SOME EARLIER TIME.