Narrative:

I departed runway 28 from dpa with an instrument clearance for a local flight to pwk. Following instructions, I turned right to a heading of 360 degrees and contacted chicago departure/approach (frequency 133.5). Upon reaching my assigned altitude of 3000 ft MSL. I was instructed to get ATIS at pwk and report back on frequency. I successfully received ATIS from pwk. When I tried to re- establish contact with the controller, I could not do so. When I pressed the push-to-talk switch on the yoke with my left thumb, I could not hear my voice in my headset. There was no response to my attempts to transmit. At this point, I noticed something else unusual. After I released the push-to-talk switch, I could hear the sound of an open channel for about 2 seconds, after which the channel appeared to close. I could not transmit when I pushed the push-to-talk switch. However, it appeared that there was a 2-SECOND window in which transmission might have been possible immediately after the push-to-talk switch was released. I concluded that 2-WAY radio communication was no longer possible. I continued to transmit messages, hoping that someone could hear me. I never heard anything more on the radio. Contributing factors: the temperature and dewpoint at dpa on the ground was 33/31 degrees F, straddling freezing. Perhaps the temperature contributed to radio problems. I decided to return to the departure airport, dpa. I vectored myself around and flew the ILS 10 approach. The navigation radios worked normally. I broke out at about 1000 ft AGL and landed on runway 10 without a clearance and without incident. Very quickly, I decided that the transceiver had failed. This may have been premature. The following options were not tried: using the speaker instead of the head set. Using the hand microphone instead of the microphone on the headset and the push-to-talk switch on the yoke. Checking to ensure that all plugs were inserted into the jacks. Checking the selector switches for the radio on the control panel. Cycling the radios. I did not set my transponder properly to indicate a radio problem (7600). I did not circle the airport to determine the traffic before landing. Factors affecting the quality of human performance: I was not familiar with the proper procedures to follow during a loss of 2-WAY radio communication. I have since reviewed the following: 2-WAY radio communication failure, transponder operation during 2- way radio communication failure, re-establishing radio contact, communication with tower when aircraft transmitter or receiver or both are inoperative. ARTCC radio frequency outage, traffic control light signals, and taxiing. Far 91.185, IFR operations. 2-WAY radio communication failure. I did not remember the light signals, so I was not able to respond promptly to the tower's usage of light signals.

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Original NASA ASRS Text

Title: LOSS OF RADIO CONTACT CAUSES PLT TO RETURN LAND WITHOUT REVISED CLRNC.

Narrative: I DEPARTED RWY 28 FROM DPA WITH AN INST CLRNC FOR A LCL FLT TO PWK. FOLLOWING INSTRUCTIONS, I TURNED R TO A HDG OF 360 DEGS AND CONTACTED CHICAGO DEP/APCH (FREQ 133.5). UPON REACHING MY ASSIGNED ALT OF 3000 FT MSL. I WAS INSTRUCTED TO GET ATIS AT PWK AND RPT BACK ON FREQ. I SUCCESSFULLY RECEIVED ATIS FROM PWK. WHEN I TRIED TO RE- ESTABLISH CONTACT WITH THE CTLR, I COULD NOT DO SO. WHEN I PRESSED THE PUSH-TO-TALK SWITCH ON THE YOKE WITH MY L THUMB, I COULD NOT HEAR MY VOICE IN MY HEADSET. THERE WAS NO RESPONSE TO MY ATTEMPTS TO XMIT. AT THIS POINT, I NOTICED SOMETHING ELSE UNUSUAL. AFTER I RELEASED THE PUSH-TO-TALK SWITCH, I COULD HEAR THE SOUND OF AN OPEN CHANNEL FOR ABOUT 2 SECONDS, AFTER WHICH THE CHANNEL APPEARED TO CLOSE. I COULD NOT XMIT WHEN I PUSHED THE PUSH-TO-TALK SWITCH. HOWEVER, IT APPEARED THAT THERE WAS A 2-SECOND WINDOW IN WHICH XMISSION MIGHT HAVE BEEN POSSIBLE IMMEDIATELY AFTER THE PUSH-TO-TALK SWITCH WAS RELEASED. I CONCLUDED THAT 2-WAY RADIO COM WAS NO LONGER POSSIBLE. I CONTINUED TO XMIT MESSAGES, HOPING THAT SOMEONE COULD HEAR ME. I NEVER HEARD ANYTHING MORE ON THE RADIO. CONTRIBUTING FACTORS: THE TEMP AND DEWPOINT AT DPA ON THE GND WAS 33/31 DEGS F, STRADDLING FREEZING. PERHAPS THE TEMP CONTRIBUTED TO RADIO PROBS. I DECIDED TO RETURN TO THE DEP ARPT, DPA. I VECTORED MYSELF AROUND AND FLEW THE ILS 10 APCH. THE NAV RADIOS WORKED NORMALLY. I BROKE OUT AT ABOUT 1000 FT AGL AND LANDED ON RWY 10 WITHOUT A CLRNC AND WITHOUT INCIDENT. VERY QUICKLY, I DECIDED THAT THE TRANSCEIVER HAD FAILED. THIS MAY HAVE BEEN PREMATURE. THE FOLLOWING OPTIONS WERE NOT TRIED: USING THE SPEAKER INSTEAD OF THE HEAD SET. USING THE HAND MIKE INSTEAD OF THE MIKE ON THE HEADSET AND THE PUSH-TO-TALK SWITCH ON THE YOKE. CHKING TO ENSURE THAT ALL PLUGS WERE INSERTED INTO THE JACKS. CHKING THE SELECTOR SWITCHES FOR THE RADIO ON THE CTL PANEL. CYCLING THE RADIOS. I DID NOT SET MY XPONDER PROPERLY TO INDICATE A RADIO PROB (7600). I DID NOT CIRCLE THE ARPT TO DETERMINE THE TFC BEFORE LNDG. FACTORS AFFECTING THE QUALITY OF HUMAN PERFORMANCE: I WAS NOT FAMILIAR WITH THE PROPER PROCS TO FOLLOW DURING A LOSS OF 2-WAY RADIO COM. I HAVE SINCE REVIEWED THE FOLLOWING: 2-WAY RADIO COM FAILURE, XPONDER OP DURING 2- WAY RADIO COM FAILURE, RE-ESTABLISHING RADIO CONTACT, COM WITH TWR WHEN ACFT XMITTER OR RECEIVER OR BOTH ARE INOP. ARTCC RADIO FREQ OUTAGE, TFC CTL LIGHT SIGNALS, AND TAXIING. FAR 91.185, IFR OPS. 2-WAY RADIO COM FAILURE. I DID NOT REMEMBER THE LIGHT SIGNALS, SO I WAS NOT ABLE TO RESPOND PROMPTLY TO THE TWR'S USAGE OF LIGHT SIGNALS.

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.