NMAC AS SMT TWIN PERFORMS AN UNAUTH PENETRATION OF AIRSPACE.

Narrative

TOOK OFF FROM HOME BASE N54-LANGHORNE; PA; PM LCL TIME FOR VFR FLT TO WWD (CAPE MAY; NJ). USING ARD (YARDLEY VOR) 185 DEG RADIAL AND RNAV (LORAN-C) TO NAV. DEPARTED RWY 24; TURNED L DURING CLB TO 190 DEG HDG; CALLED PHILADELPHIA APCH ON 123.8 TO ASK FOR RADAR ADVISORIES. GOT XPONDER CODE; HIT IDENT AS REQUESTED; CALL BACK WAS RADAR CONTACT; PROCEED ON COURSE. NOT SURE IF I WAS STILL I CLB OR LEVELING OFF AT PLANNED ALT OF 2500 FT. I STARTED TO SEE AN AIRPLANE OFF MY R. CTLR CALLED TO ASK IF I HAD CONTACTED NE PHILADELPHIA TWR. I REPLIED 'NEGATIVE.' STILL WATCHING TFC AND NO CALL CAME FOR TFC FROM PHL APCH. MADE 45 DEG L BANK TURN AND PUSHED NOSE DOWN TO AVOID COLLISION. OTHER PLANE WAS SINGLE ENG FIXED GEAR LOW-WING TYPE. UNQUESTIONABLY CLOSEST TFC ENCOUNTER I EVER HAD. PROBABLY WOULD HAVE BEEN A MIDAIR IF I HAD NOT TAKEN EVASIVE ACTION. I RECOVERED ON A HDG OF 120 DEGS (I HAD NOT NOTICED WHAT HDG WAS WHEN I STARTED). UPON RECOVERY AS I LEVELED OFF CTLR HANDED ME OFF TO NEXT SECTOR 126.6. I STARTED CLBING BACK TO 2500 FT AND TRIED TO RELAX WHEN I SAW 2 HOT AIR BALLOONS AT ABOUT 1000 FT HIGHER AND 5 MI AWAY. NOT A COLLISION SIT -- BUT ANOTHER UNEXPECTED SIGHTING. I THEN GOT BACK ON COURSE; LEVELED OFF AT 2500 FT AND CONTINUED THE REST OF MY UNEVENTFUL FLT. MY PURPOSES FOR SENDING THIS RPT ARE: EVEN WHEN IN RADAR CONTACT FOR ADVISORIES YOU CANNOT DEPEND ON CTLRS TO CALL ALL TFC. I WAS TERRIBLY UNNERVED BY THIS EPISODE BUT NOTHING SUFFERED AND I AM SENDING THE RPT OF THIS NEAR-MISS TO REINFORCE. WE MUST LOOK OUT THE WINDOW AS PLTS. CTLRS MUST HELP COLLISION AVOIDANCE AS MUCH AS THEY POSSIBLY CAN. WE MUST ALL KEEP OUR XPONDERS TURNED ON ALL THE TIME.