Narrative:

While flying as copilot on large transport we began to experience intermittent transmission with center (atl). Center was advised that it appeared that we were about to lose transmission capabilities. Attempted to communication from all 3 cockpit locations on both VHF radios. Ultimately we lost all ability to transmit to center. Since we could receive all xmissions I elected to squawk lost communication code of 7600. I inadvertently put 7500 in the transponder. For the balance of the flight (30 mins) ATC directions were acknowledged by utilizing the identify feature. Our company notified us by ACARS and asked us to verify the nature of our emergency. At that time the correct code of 7600 was placed in the transponder. The flight engineer established communications with the tower, while on short final, and informed the tower that communication was the only difficulty being experienced by our aircraft. Supplemental information from acn 125087: there was confusion over how we should troubleshoot and who should take what actions. The captain could have been more directive and managed the crew differently.

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Original NASA ASRS Text

Title: ACR LGT LOST VHF RADIO TRANSMISSION CAPABILITY BETWEEN MOB AND BNA. FO SET HIJACK CODE IN TRANSPONDER INSTEAD OF LOST COM CODE.

Narrative: WHILE FLYING AS COPLT ON LGT WE BEGAN TO EXPERIENCE INTERMITTENT XMISSION WITH CENTER (ATL). CENTER WAS ADVISED THAT IT APPEARED THAT WE WERE ABOUT TO LOSE XMISSION CAPABILITIES. ATTEMPTED TO COM FROM ALL 3 COCKPIT LOCATIONS ON BOTH VHF RADIOS. ULTIMATELY WE LOST ALL ABILITY TO XMIT TO CENTER. SINCE WE COULD RECEIVE ALL XMISSIONS I ELECTED TO SQUAWK LOST COM CODE OF 7600. I INADVERTENTLY PUT 7500 IN THE XPONDER. FOR THE BALANCE OF THE FLT (30 MINS) ATC DIRECTIONS WERE ACKNOWLEDGED BY UTILIZING THE IDENT FEATURE. OUR COMPANY NOTIFIED US BY ACARS AND ASKED US TO VERIFY THE NATURE OF OUR EMER. AT THAT TIME THE CORRECT CODE OF 7600 WAS PLACED IN THE XPONDER. THE FLT ENGINEER ESTABLISHED COMS WITH THE TWR, WHILE ON SHORT FINAL, AND INFORMED THE TWR THAT COM WAS THE ONLY DIFFICULTY BEING EXPERIENCED BY OUR ACFT. SUPPLEMENTAL INFORMATION FROM ACN 125087: THERE WAS CONFUSION OVER HOW WE SHOULD TROUBLESHOOT AND WHO SHOULD TAKE WHAT ACTIONS. THE CAPT COULD HAVE BEEN MORE DIRECTIVE AND MANAGED THE CREW DIFFERENTLY.

Data retrieved from NASA's ASRS site as of August 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.