AN ACR CAPT RPTS THAT HIS FO CAUSED A STUCK MIKE.

Narrative

ACFT WAS PARKED AT THE GATE WHILE WE WERE PREPARING FOR DEP OF SCHEDULED FLT. FO WAS ON BOARD PERFORMING HIS PREFLT DUTIES. I JOINED HIM IN THE COCKPIT A SHORT TIME LATER; AND UPON DONNING MY HEADSET; OBSERVED A SIDE TONE; AND COULD HEAR MUFFLED CONVERSATION FROM THE COCKPIT COMING THROUGH MY EARPIECE. OBVIOUSLY; A STUCK MIKE WAS INDICATED. I CHKED MY MIKE BUTTONS AND AUDIO PANEL; AND HAD THE FO DO THE SAME ON HIS SIDE; AND I ALSO LOOKED AT THE OBSERVER STATION AUDIO PANEL; BUT COULD NOT FIND THE PROB. WE FINALLY DISCOVERED THAT THE FO HAD HUNG HIS UNIFORM COAT ON THE MIKE HOLDER AT THE OBSERVER STATION; AND THE COAT WAS PUSHING THE XMIT BUTTON ON THE HAND MIKE; HANGING ON THE BRACKET. ONCE THE COAT WAS REMOVED; THE PROB WAS SOLVED. THE PROB OF STOWING FLC COATS; BAGS; ETC; IS A DEFINITE PROB ON THE MLG ACFT. SOME VERSIONS HAVE A SMALL COMPARTMENT OPPOSITE THE JUMP SEAT; BUT MOST HAVE NO COCKPIT STORAGE AT ALL. USUALLY; CREW ITEMS ARE STOWED IN THE PAX CABIN; WHICH MEANS THEY ARE MIXED IN WITH THE PAX CARRY-ON BAGGAGE. THIS COMPROMISES THE SECURITY OF THE CREW'S ITEMS.