TEMPORARY LOSS OF COM OCCURRED WHEN THE CAPT'S PA HANDSET DROPPED ON THE CTR RADIO CONSOLE; DISABLING SELECTION CAPABILITY OF BOTH VHF'S FOR ALL OF THE CREW 100 MI S OF ORD; IL.

Narrative

KNOX ARR. DURING OUR DSCNT TO FL250 FOR A LNDG AT CHICAGO; THE CAPT MADE A BEFORE LNDG ANNOUNCEMENT TO THE CABIN USING THE CTR CONSOLE PA HANDSET. DURING THE STOWING OF THE PA HANDSET; IT SIPPED OUT OF THE CAPT'S HAND AND LANDED ON THE CTR CONSOLE. A FEW MINS LATER; THE FO ASKED THE CAPT TO REQUEST A LOWER ALT FROM ATC. THE CAPT TRIED TO CONTACT ATC; HOWEVER; THERE WAS NO RESPONSE. THE FO TRIED HER MIKE AND THE RELIEF PLT TRIED HIS MIKE WITH NO RESPONSE FROM ATC. IN THE PROCESS OF SETTING UP OUR #2 VHF COMRDO FOR USE ATC CONTACTED US ON GUARD 121.5 AND ISSUED US A NEW FREQ. SELECTING THE NEW FREQ IN THE #2 RADIO CONTINUED TO BRING SILENCE. WE THEN KNEW THAT THE DROPPING OF THE PA HANDSET ON THE CTR CONSOLE DESELECTED HIS MIKE SYS FROM BEING USED WITH EITHER RADIO AND BOTH THE FO'S WERE ABLE TO COMMUNICATE WITH ATC FOR THE REMAINDER OF THE FLT. AFTER ARRIVING AT ORD; THE CAPT'S VHF COM SYS WAS ENTERED IN THE ACFT LOGBOOK FOR REPAIR. FOR FUTURE FLTS; I WILL MAKE SURE THE PA HANDSET AND ITS CORD ARE IN BETTER CTL. SUPPLEMENTAL INFO FROM ACN 541129: WHENEVER CAPT SELECTED ANYTHING ON HIS MIKE SELECTOR PANEL IT BLOCKED OUT EVERYTHING. CAPT DESELECTED HIS COM AND THE FO MADE THE REMAINDER OF THE COMS WITHOUT INCIDENT.