Narrative:

10-20 mi prior to reaching ape the radios began to develop static and radio xmissions were becoming more difficult to understand. When the flight reached ape the radio communication problem had become worse, and the crew could no longer hear ATC instructions. The crew came to the conclusion that the radios were probably being affected by undischarged static due to the WX they were experiencing. 10 mins passed, as the crew tried to reestablish communications and troubleshoot the problem. The communication and navigation identify portion of the radios were unusable due to the static interference. The crew could not communicate with or identify any new navaids after appleton VOR including their next fix of waterville VOR and the ILS system at ZZZ, which concerned them in the following of the appropriate regulation for this situation. By this point the crew was less than 75 mi outside of the destination airport and decided it as an appropriate situation to squawk 7600. The crew then changed the transponder code from the ATC assigned code to the radio failure code of 7600. The crew then heard the call sign of the flight and an instruction by center to start a descent to FL200. The crew tried to acknowledge and confirm descent level but were unsure if ATC could hear them. Both pilots agreed that it most likely had to be WX induced static so they thought a descent would only help the situation in the event they could get into visual meteorological condition (VMC). In this case VMC would have contributed to the safety of the flight by clearing the static and also allowing them to cancel the IFR flight plan and free up the controled airspace. The base of the clouds was forecast to be at 8000 ft broken. So the crew started the descent to 20000 ft or the route MEA if required and made an intention call to ZID in an attempt to keep them informed if ATC was able to receive their radio transmission, even though the crew was unable to receive ctrs. Somewhere between 20000 ft and 17000 ft they heard ZID hand them off to ZOB. The crew tried to contact cleveland and continue the descent. They successfully contacted tower which told them to continue to 11000 ft. During this time the radios started to improve. Prior to reaching 11000 ft the radio static cleared and normal communications were established and the crew stopped squawking 7600. From cleveland on, the radios worked fine. Approach was the last controller they talked to, and received vectors from, to the ILS runway 25. With a visual on the airport, and tower clearing them to land, the flight ended without any other problems. Upon clearing runway 25 the crew was instructed by tower to contact ZID. The supervisor informed the PIC that the crew had violated several procedures and said that he wished they would have declared an emergency via 7700 and then 7600, instead of 7600 outright. He also stated the crew should have maintained their altitude until reaching the initial approach fix on the localizer and then started their descent from FL240 at their ETA. The crew discussed their decision afterwards, pointing out that they could not identify the localizer, initial approach fix, ATIS or holding pattern without radio identify capability. Nor did they think they would be able to receive a localizer 24000 ft above the ground. They thought they had used their best judgement in getting down to a lower altitude, (the MEA if required), for the benefits they had initially discussed that in the end helped the situation. The crew came to the conclusion that this type of radio failure in class a airspace is not addressed by crash fire rescue equipment 14 far part 91.185. I feel like we used our best judgement to bring the flight to a safe conclusion.

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Original NASA ASRS Text

Title: FA20 FLT CREW SQUAWKS 7600 AND DSNDS BELOW LAST ASSIGNED ALT IN AN ATTEMPT TO RESTORE WX INDUCED COM FAILURE. COM REESTABLISHED AT LOWER ALT. ATC QUESTIONS FLT CREW PROC AFTER VFR LNDG AT DEST.

Narrative: 10-20 MI PRIOR TO REACHING APE THE RADIOS BEGAN TO DEVELOP STATIC AND RADIO XMISSIONS WERE BECOMING MORE DIFFICULT TO UNDERSTAND. WHEN THE FLT REACHED APE THE RADIO COM PROB HAD BECOME WORSE, AND THE CREW COULD NO LONGER HEAR ATC INSTRUCTIONS. THE CREW CAME TO THE CONCLUSION THAT THE RADIOS WERE PROBABLY BEING AFFECTED BY UNDISCHARGED STATIC DUE TO THE WX THEY WERE EXPERIENCING. 10 MINS PASSED, AS THE CREW TRIED TO REESTABLISH COMS AND TROUBLESHOOT THE PROB. THE COM AND NAV IDENT PORTION OF THE RADIOS WERE UNUSABLE DUE TO THE STATIC INTERFERENCE. THE CREW COULD NOT COMMUNICATE WITH OR IDENT ANY NEW NAVAIDS AFTER APPLETON VOR INCLUDING THEIR NEXT FIX OF WATERVILLE VOR AND THE ILS SYS AT ZZZ, WHICH CONCERNED THEM IN THE FOLLOWING OF THE APPROPRIATE REG FOR THIS SIT. BY THIS POINT THE CREW WAS LESS THAN 75 MI OUTSIDE OF THE DEST ARPT AND DECIDED IT AS AN APPROPRIATE SIT TO SQUAWK 7600. THE CREW THEN CHANGED THE XPONDER CODE FROM THE ATC ASSIGNED CODE TO THE RADIO FAILURE CODE OF 7600. THE CREW THEN HEARD THE CALL SIGN OF THE FLT AND AN INSTRUCTION BY CTR TO START A DSCNT TO FL200. THE CREW TRIED TO ACKNOWLEDGE AND CONFIRM DSCNT LEVEL BUT WERE UNSURE IF ATC COULD HEAR THEM. BOTH PLTS AGREED THAT IT MOST LIKELY HAD TO BE WX INDUCED STATIC SO THEY THOUGHT A DSCNT WOULD ONLY HELP THE SIT IN THE EVENT THEY COULD GET INTO VISUAL METEOROLOGICAL CONDITION (VMC). IN THIS CASE VMC WOULD HAVE CONTRIBUTED TO THE SAFETY OF THE FLT BY CLRING THE STATIC AND ALSO ALLOWING THEM TO CANCEL THE IFR FLT PLAN AND FREE UP THE CTLED AIRSPACE. THE BASE OF THE CLOUDS WAS FORECAST TO BE AT 8000 FT BROKEN. SO THE CREW STARTED THE DSCNT TO 20000 FT OR THE RTE MEA IF REQUIRED AND MADE AN INTENTION CALL TO ZID IN AN ATTEMPT TO KEEP THEM INFORMED IF ATC WAS ABLE TO RECEIVE THEIR RADIO XMISSION, EVEN THOUGH THE CREW WAS UNABLE TO RECEIVE CTRS. SOMEWHERE BTWN 20000 FT AND 17000 FT THEY HEARD ZID HAND THEM OFF TO ZOB. THE CREW TRIED TO CONTACT CLEVELAND AND CONTINUE THE DSCNT. THEY SUCCESSFULLY CONTACTED TWR WHICH TOLD THEM TO CONTINUE TO 11000 FT. DURING THIS TIME THE RADIOS STARTED TO IMPROVE. PRIOR TO REACHING 11000 FT THE RADIO STATIC CLRED AND NORMAL COMS WERE ESTABLISHED AND THE CREW STOPPED SQUAWKING 7600. FROM CLEVELAND ON, THE RADIOS WORKED FINE. APCH WAS THE LAST CTLR THEY TALKED TO, AND RECEIVED VECTORS FROM, TO THE ILS RWY 25. WITH A VISUAL ON THE ARPT, AND TWR CLRING THEM TO LAND, THE FLT ENDED WITHOUT ANY OTHER PROBS. UPON CLRING RWY 25 THE CREW WAS INSTRUCTED BY TWR TO CONTACT ZID. THE SUPVR INFORMED THE PIC THAT THE CREW HAD VIOLATED SEVERAL PROCS AND SAID THAT HE WISHED THEY WOULD HAVE DECLARED AN EMER VIA 7700 AND THEN 7600, INSTEAD OF 7600 OUTRIGHT. HE ALSO STATED THE CREW SHOULD HAVE MAINTAINED THEIR ALT UNTIL REACHING THE INITIAL APCH FIX ON THE LOC AND THEN STARTED THEIR DSCNT FROM FL240 AT THEIR ETA. THE CREW DISCUSSED THEIR DECISION AFTERWARDS, POINTING OUT THAT THEY COULD NOT IDENT THE LOC, INITIAL APCH FIX, ATIS OR HOLDING PATTERN WITHOUT RADIO IDENT CAPABILITY. NOR DID THEY THINK THEY WOULD BE ABLE TO RECEIVE A LOC 24000 FT ABOVE THE GND. THEY THOUGHT THEY HAD USED THEIR BEST JUDGEMENT IN GETTING DOWN TO A LOWER ALT, (THE MEA IF REQUIRED), FOR THE BENEFITS THEY HAD INITIALLY DISCUSSED THAT IN THE END HELPED THE SIT. THE CREW CAME TO THE CONCLUSION THAT THIS TYPE OF RADIO FAILURE IN CLASS A AIRSPACE IS NOT ADDRESSED BY CFR 14 FAR PART 91.185. I FEEL LIKE WE USED OUR BEST JUDGEMENT TO BRING THE FLT TO A SAFE CONCLUSION.

Data retrieved from NASA's ASRS site as of July 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.