Narrative:

I was approaching the class C controled airspace of dsm, ia. I had got the WX and then called the approach to request permission to land at dsm. At this time I was still outside of the airspace and trying to establish 2-WAY radio communication. The reply I received was that the ATC controller could hear my microphone being keyed, but could not hear my voice. I repeated my call and he again replied no voice. ATC then asked for the airplane calling approach to squawk a unique frequency and to identify. I complied with the instruction. ATC then advised me that radar contact was made and that I should fly in for runway 13. Further commands were then given by ATC each time asking for confirmation by pressing identify. I made straight-in and landed on runway 13 and was then guided directly to the radio shop. A minor short circuit was discovered and repaired and I then departed for dsm class C airspace. I had heard traffic on the way down to dsm, so I realize that this is a busy airport and hope to not have a recurrence of this problem.

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Original NASA ASRS Text

Title: PA28 PLT LNDG DSM IS ABLE TO HEAR DSM APCH CTL ON RADIO, BUT IS UNABLE TO XMIT.

Narrative: I WAS APCHING THE CLASS C CTLED AIRSPACE OF DSM, IA. I HAD GOT THE WX AND THEN CALLED THE APCH TO REQUEST PERMISSION TO LAND AT DSM. AT THIS TIME I WAS STILL OUTSIDE OF THE AIRSPACE AND TRYING TO ESTABLISH 2-WAY RADIO COM. THE REPLY I RECEIVED WAS THAT THE ATC CTLR COULD HEAR MY MIKE BEING KEYED, BUT COULD NOT HEAR MY VOICE. I REPEATED MY CALL AND HE AGAIN REPLIED NO VOICE. ATC THEN ASKED FOR THE AIRPLANE CALLING APCH TO SQUAWK A UNIQUE FREQ AND TO IDENT. I COMPLIED WITH THE INSTRUCTION. ATC THEN ADVISED ME THAT RADAR CONTACT WAS MADE AND THAT I SHOULD FLY IN FOR RWY 13. FURTHER COMMANDS WERE THEN GIVEN BY ATC EACH TIME ASKING FOR CONFIRMATION BY PRESSING IDENT. I MADE STRAIGHT-IN AND LANDED ON RWY 13 AND WAS THEN GUIDED DIRECTLY TO THE RADIO SHOP. A MINOR SHORT CIRCUIT WAS DISCOVERED AND REPAIRED AND I THEN DEPARTED FOR DSM CLASS C AIRSPACE. I HAD HEARD TFC ON THE WAY DOWN TO DSM, SO I REALIZE THAT THIS IS A BUSY ARPT AND HOPE TO NOT HAVE A RECURRENCE OF THIS PROB.

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.