SMA ON IFR FLT HAS LOST COM.

Narrative

ON AN IFR FLT FROM GON TO DCA. APCHING SWANN INTXN; EITHER MAGUIRE APCH OR ANOTHER PLANE ON 120.25 HAD A STUCK MIKE. (MY INTERCOM HAS A RED XMIT LIGHT; WHICH WAS NOT ON; SO I DON'T THINK MY MIKE WAS STUCK.) FOR THE NEXT 5-10 MINS ALL COMS ON THIS FREQ WERE UNUSABLE. ABOUT 10 MINS LATER THE STUCK MIKE WAS CLRED. AT THIS TIME I WAS NO LONGER ABLE TO HEAR MAGUIRE APCH BUT COULD HEAR OTHER ACFT TALKING TO MAGUIRE. I ATTEMPTED TO CONTACT MAGUIRE OR OTHER ACFT ON 120.25 WITHOUT SUCCESS. BY THIS TIME I WAS APPROX 25 NM NE OF DCA ON V123; MY CLRED RTE. I ATTEMPTED TO RAISE DCA APCH ON 118.75 (NEAREST FREQ PRINTED ON L26 CHART) WITHOUT SUCCESS. SINCE COMS WERE LOST I SQUAWKED 7600 AND IMMEDIATELY RAISED DCA ON EMER FREQ 121.50. DCA SHIFTED ME TO 124.20 AND HAD ME RETURN TO ORIGINAL XPONDER CODE. THE FLT WAS THEN COMPLETED WITHOUT INCIDENT. AFTER LNDG I CONTACTED LEESBURG FSS TO SEE IF ANY INFO ON THIS INCIDENT WAS NEEDED. AFTER CHKING WITH DCA APCH; LEESBURG FSS SAID NO FURTHER INFO WAS REQUIRED. LESSON LEARNED: LOST COMS PROC; DRILLED IN YRS AGO BY MY CFII; WORKED SMOOTHLY AND QUICKLY.