Narrative:

I was working two sectors combined. About 2-3 minutes before I was going to be relieved; I noticed aircraft X went into coast track about 12 miles north of ZZZ and I asked him to verify altitude. He read back 4000 feet. I told him his radar contact was lost and to try a number 2 transponder if he had one. The pilot replied 'we'll try... Transponder' and he was starting to break up. I had other VFR's and IFR's with a couple of inbounds I needed to get down; so I started speaking to them while aircraft X could hopefully troubleshoot. I then came back and attempted communication and the radio was still garbled. Since he was a low altitude general aviation aircraft; I started to think he was in a bad area to communicate with ATC and told him to try his number 2 radio. I started my relief briefing; in the middle of my relief briefing I attempted communication with aircraft X and his response started to get a little more garbled but since a new radar controller was coming in; I suggested that he/she give aircraft X an alternate clearance so he could be on the airway. At this point; I assumed his transponder was broken and I would have to use non-radar procedures to get the aircraft to his destination. As soon as the new radar controller sat down aircraft X lost his radio completely. It was his only one. We lost his transponder; his only radio; and we could not even put him on the airway in time. The situation deteriorated pretty fast. I stuck around and assisted the radar controller. The radar controller tried to contact him through ZZZ tower on a handheld radio and everyone was blocking for him and cleared him to the ZZZ airport; we didn't notice anything and there was no feedback. We finally found out later the aircraft had a complete electrical failure and was talking on guard 121.5 to approach. We eventually found out the aircraft left our airspace. Recommendation; all aircraft should have backup equipment; required by law.

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Original NASA ASRS Text

Title: Enroute controller described loss of transponder/radio event; later to discover the aircraft experienced complete electrical failure; controller noting all IFR aircraft should be required to have appropriate back-up equipment.

Narrative: I was working two sectors combined. About 2-3 minutes before I was going to be relieved; I noticed Aircraft X went into coast track about 12 miles north of ZZZ and I asked him to verify altitude. He read back 4000 feet. I told him his radar contact was lost and to try a number 2 transponder if he had one. The pilot replied 'We'll try... transponder' and he was starting to break up. I had other VFR's and IFR's with a couple of inbounds I needed to get down; so I started speaking to them while Aircraft X could hopefully troubleshoot. I then came back and attempted communication and the radio was still garbled. Since he was a low altitude general aviation aircraft; I started to think he was in a bad area to communicate with ATC and told him to try his number 2 radio. I started my relief briefing; in the middle of my relief briefing I attempted communication with Aircraft X and his response started to get a little more garbled but since a new Radar Controller was coming in; I suggested that he/she give Aircraft X an alternate clearance so he could be on the airway. At this point; I assumed his transponder was broken and I would have to use non-radar procedures to get the aircraft to his destination. As soon as the new Radar Controller sat down Aircraft X lost his radio completely. It was his only one. We lost his transponder; his only radio; and we could not even put him on the airway in time. The situation deteriorated pretty fast. I stuck around and assisted the Radar Controller. The Radar Controller tried to contact him through ZZZ Tower on a handheld radio and everyone was blocking for him and cleared him to the ZZZ airport; we didn't notice anything and there was no feedback. We finally found out later the aircraft had a complete electrical failure and was talking on Guard 121.5 to Approach. We eventually found out the aircraft left our airspace. Recommendation; all aircraft should have backup equipment; required by law.

Data retrieved from NASA's ASRS site as of April 2012 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.