BLOCKED FREQS BY A STUCK MIKE ON A B737-700 GOING INTO BWI; MD.

Narrative

DSNDING FROM CRUISE ALT; THE CAPT AND I REALIZED THERE WAS A STUCK MIKE ON FREQ. BECAUSE I COULD HEAR SIDE TONE; I KNEW THE STUCK MIKE WAS OURS. WE QUICKLY CHKED ALL 4 MIKES (2 HAND HELD PLUS 2 YOKE MIKE XMITTERS). AT TIMES; WE GOT IT FIXED ONLY TO HAVE IT STICK AGAIN. IN THE PROCESS; AND NOT KNOWING WHICH SWITCH IT WAS WE BLOCKED SEVERAL FREQS ON THE WAY INTO BWI. WE ALSO HAD TO SQUAWK 7600 FOR LOST COM; HOWEVER; THE CAPT INADVERTENTLY SQUAWKED 7500 (HIJACK) BRIEFLY. THE BAD SWITCH WAS THE CAPT'S SIDE YOKE XMITTING SWITCH. THE CAPT UNPLUGGED HIS HEADSET AND I USED RADIO #2 AND LANDED THE AIRPLANE AT BWI. IN THE PROCESS WE ENDED UP BLOCKING SEVERAL FREQS UNTIL WE ARRIVED AT THE GATE; THEN FIGURED OUT WHY. ALTHOUGH THE CAPT HAD UNPLUGGED HIS HEADSET; THE MIKE SELECTOR WAS STILL XMITTING ON RADIO #1. 3 THINGS WE LEARNED ABOUT STUCK MIKES: 1) IF YOU HEAR SIDE TONE SIMILAR TO WHEN ONE PLT IS XMITTING NORMALLY AND THE FREQ HAS A STUCK MIKE; THE STUCK MIKE IS YOURS. 2) DON'T FLIP TOO MANY SWITCHES OR BUTTONS AT FIRST. STOP; AND TRY TO REMEMBER WHO XMITTED LAST. THIS WILL MAKE IT EASIER TO FIND WHICH MIKE ON WHICH SIDE IS HOT. 3) EVEN IF YOU UNPLUG THE HOT SIDE HEADSET; YOU WILL STILL BE XMITTING UNTIL THE MIKE SELECTOR SWITCH IS DESELECTED FROM COM #1 AND COM #2. A GOOD PLACE TO SELECT WOULD BE FLT INTERPHONE.