C172 INSTRUCTOR PLT EXPRESSED CONCERN REGARDING NHK TRACON VECTORS FOR ILS APCH TO ESN.

Narrative

WHILE BEING VECTORED TO FINAL FOR THE ILS RWY 4 APCH AT ESN; THE CTLR BROUGHT US IN FROM THE E SIDE OF THE ARPT; INITIALLY ON A 270 DEG VECTOR; THEN ON A 310 DEG VECTOR. WE CROSSED THE ILS LOC ON A HDG OF 310 DEGS ABOUT 12 MI FROM THE ARPT; AT WHICH TIME THE CTLR ISSUED A R TURN HDG 030 DEGS; INSTRUCTED US TO INTERCEPT THE LOC; AND CLRED US FOR THE APCH. AT THAT POINT; WE WERE ABOUT 1 MI NW OF THE LOC; AND THE 030 DEG HDG WAS DIVERGING. DUE TO THE CLR WX; I WAS ABLE TO CONFIRM ALL LOCATIONS VISUALLY. WE WERE DEFINITELY NW OF THE CTRLINE. I INSTRUCTED MY STUDENT TO TURN R TO 060 DEGS TO INTERCEPT AND INFORMED THE CTLR WHAT WAS HAPPENING. HE SAID HE SHOWED US ABOUT 1 MI SE OF THE LOC ON HIS RADAR DISPLAY. WHEN I QUERIED HIM FURTHER; HE ADMITTED THAT THE LOC WAS NOT DEPICTED; AND THAT HE WAS USING A 221 DEG BEARING OFF THE DEPICTED LOCATION OF ESN AS THE REF FOR THE VECTOR. WE CONTINUED ON THE LOC BASED ON OUR NAV RECEIVER AND CDI; WITH THE CDI DEAD CTRED ALL THE WAY (CONFIRMED VISUALLY WITH REF TO THE RWY); AND THE CTLR CONFIRMED THAT ON HIS RADAR WE WERE TRACKING 1 OR 2 MI SE OF WHERE HE THOUGHT THE LOC WAS ALL THE WAY TO THE RWY. AFTER THE FLT; I CONFIRMED WITH OTHER INSTRUCTORS THAT THIS HAS HAPPENED BEFORE ON THIS APCH. IN A TELEPHONE CALL WITH THE BRANCH CHIEF AT THE NAS PATUXENT RIVER RAPCON; WE DETERMINED THAT PATUXENT APCH DOES NOT NORMALLY VECTOR ACFT IN THIS AREA; WHICH IS WITHIN POTOMAC APCH'S AIRSPACE; BUT THAT ON OCCASION; BY INDIVIDUAL AGREEMENT BTWN THE CTLRS OF THE AFFECTED SECTOR; PATUXENT CTLS TFC IN THIS AREA ON A 'POINTOUT' BASIS. THE PROB IS THAT PATUXENT APCH DOES NOT HAVE A VALIDATED DEPICTION OF THE ESN ILS FINAL APCH COURSE OR APCH GATE ON THEIR RADAR DISPLAY. THE SOLUTION IS FOR PATUXENT CTLRS NOT TO ACCEPT ACFT FOR VECTORING TO THE RECENTLY-ESTABLISHED ESN LOC FINAL APCH COURSE UNLESS/UNTIL THE LOC IS DEPICTED ACCURATELY ON THEIR DISPLAY. IN ADDITION; A FORMAL LOA BTWN POTOMAC APCH AND PATUXENT APCH SHOULD BE DEVELOPED TO DOCUMENT THE CAPABILITIES OF EACH FACILITY AND TO ESTABLISH ACHIEVABLE RESPONSIBILITIES FOR TFC NEAR THE BOUNDARY BTWN THE TWO.