BE58 pilot reported a loss of communication radio transmit capability and a burning smell in the coc...

Attributes
ACN	1560675
Time
Date	201807
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.TRACON
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Baron 58/58TC
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Air/Ground Communication
Person 1
Function	Single Pilot
Qualification	Flight Crew Private Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 25 Flight Crew Total 530 Flight Crew Type 230
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor

Narrative:

I was flying on an IFR flight plan to ZZZ. Over far northwest ohio I was handed off to approach. Approach gave me a revised clearance into ZZZ1. When I keyed the mic to acknowledge; there was a pop and the smell of an electrical fire in the cockpit. I told [approach] to standby; and shut down the avionics master. I simultaneously turned south toward several suitable landing fields; and began a descent. I cycled the avionics for several minutes and did not note any further burning smell. I was able to receive on communication 1 but I could not transmit. I tried to [advise ATC] but again this call was not heard. Given the possibility of an unextinguished fire; I proceeded direct to ZZZ2 and made an emergency landing. I called [approach] immediately after landing to advise them that I was on the ground and ok. If I had switched to communication 2 I would have been able to transmit. However; with the workload at the time (including a possible fire; finding an alternate; managing the descent; and trying to isolate the failure); I didn't think of trying this.

Original NASA ASRS Text

Title: BE58 pilot reported a loss of communication radio transmit capability and a burning smell in the cockpit led to a diversion.

Narrative: I was flying on an IFR flight plan to ZZZ. Over far northwest Ohio I was handed off to Approach. Approach gave me a revised clearance into ZZZ1. When I keyed the mic to acknowledge; there was a pop and the smell of an electrical fire in the cockpit. I told [Approach] to standby; and shut down the avionics master. I simultaneously turned south toward several suitable landing fields; and began a descent. I cycled the avionics for several minutes and did not note any further burning smell. I was able to receive on COM 1 but I could not transmit. I tried to [advise ATC] but again this call was not heard. Given the possibility of an unextinguished fire; I proceeded direct to ZZZ2 and made an emergency landing. I called [Approach] immediately after landing to advise them that I was on the ground and OK. If I had switched to COM 2 I would have been able to transmit. However; with the workload at the time (including a possible fire; finding an alternate; managing the descent; and trying to isolate the failure); I didn't think of trying this.

Data retrieved from NASA's ASRS site 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.