ACR MLG ACFT LOST COMS AFTER TKOF DUE TO RADIO INADVERTENTLY BEING TURNED OFF BY AN UNPLACARDED RADIO PANEL BUTTON. LOSS OF RADIO CONTACT.

Narrative

PRIOR TO TKOF; RADIOS WORKED NORMALLY. AFTER LIFTOFF AT BWI; WE LOST ALL RADIO CONTACT. I MAINTAINED RWY HDG AND CLBED TO 4000 FT MSL AS PER PDC CLRNC. CAPT TURNED TRANSPONDER TO 7600 AND TRIED TO DIAGNOSE PROBLEM WE TRIED BOTH RADIOS; BOTH MICROPHONES; SEVERAL FREQS; VHF 3 (THROUGH ACARS) -- ALL WITH NEGATIVE RESULTS. WE HEARD PARTS OF SOME XMISSIONS; BUT NOTHING ELSE. OUR CLRNC STATED 'EXPECT CLB TO ASSIGNED ALT 10 MINS AFTER TKOF; EXPECT VECTORS TO FIRST ASSIGNED FIX. AFTER 10 MINS WE BEGAN NAVIGATING; CLBING TO OUR CLRNC ALT AND HDG TOWARD FLUKY (BWI 240 DEG RADIAL 63 NM). AT ABOUT THE SAME TIME; I DEPRESSED AN UNPLACARDED BUTTON ON MY COM PANEL AND COMS WERE MYSTERIOUSLY RESTORED. WE REESTABLISHED COM WITH WASHINGTON DEP AND CONTINUED OUR FLT TO ATLANTA WITHOUT FURTHER EVENT. AFTER LNDG ALL RADIO WORKED NORMALLY. THE ACFT HAD A MAINT WRITE-UP PREVIOUSLY. CAPT'S MIKE STICKS -- MICROPHONE REPLACED. WE DISCUSSED PROBLEM WITH MAINT AT ATLANTA; WROTE IT UP; AND ASKED THAT COM SELECTOR BOXES BE REPLACED; AS A MIN.