Narrative:

I preflighted...an experimental [electrically powered] light sport plane.... As part of the preflight; I confirmed the charge was at least 97% in accordance with established procedures. Before departure; I checked the weather online and called FSS to get an abbreviated briefing; including a check of tfrs and notams. I boarded; completed the checklist; checked the controls and electrical system and departed.... Just before departure; the timer on the aircraft panel said approximately 3:40 elapsed and zero RPM voltage was 73.84v. I departed...using around 95% throttle with at least 24 KW/h for a power setting and the takeoff roll was normal. After liftoff; around midfield...; I reduced power to 22KW/h for the climb. I turned left crosswind...at around 300 to 400 feet above ground level still climbing. I had planned on climbing to an altitude of around 2;000 feet (500 to 600 feet AGL) and orbiting over the quarry and empty field south of the...freeway in compliance with the special airworthiness certificate and operating limitations of the aircraft. After turning left downwind (westbound)...at around 1;800-1;900 feet MSL; I heard a pop similar to the sound of a circuit breaker and the motor lost all power. Before this happened; the motor was still using 22KW/h; no components; esc (electronic speed controller); motor; or battery had shown any unusual temperatures and the timer read 5:06. I began to troubleshoot and glide while continuing the left turn toward the south; over the rock pit. I tried the throttle through its entire range of motion several times; the silver cutoff switch on the left panel; and the key on the right side of the panel. Nothing solved the problem so I pulled the emergency cutoff jumper. At this time I declared an emergency on the...unicom and stated I had lost all power and would be landing on the road.... I chose this location as I was too high to land on the flat gravel on the mining property and didn't want to be stuck behind a fence. I ignored the grass south of the [freeway] because I didn't think I could turn around and land before running out of altitude. I was too far to make it to the airport runway. I was nose down; gliding around 75KPH; headed eastbound. As I descended; I realized I was headed for a traffic light support pole and rather than stall the plane; I glided over the traffic lights on the west side of the intersection; and under the traffic lights on the east side. I landed; checked that traffic behind me had stopped and secured the brs safety pin and shut down the remaining equipment.... City police arrived in less than a minute and helped stop traffic and push the plane into a side road. By this time a truck from the airport had already arrived and the police helped clear traffic while we towed the aircraft to the airport. There were no injuries; no damage to the aircraft and no damage to persons or property on the ground.after the plane was back in the hangar; the a&P/ia in charge of maintenance arrived and did some basic troubleshooting. He determined the esc was the problem. A test run of the motor resulted in sparks from the esc and the same snap noise I had heard in flight. The cover of this component was removed and we determined that at least one of the...power transistors onboard had catastrophically failed.even though things turned out ok; I was complacent. I knew the aircraft was experimental; but because others had flown it successfully; I was caught somewhat off-guard by the sudden engine failure. In addition; I found out the day after the incident that the temperature gauge for the esc was not really functional; even though it appeared to be. This functionality is coming in the next software update for the glass panel. Had I known this I would have either not flown or been more wary and alert at high power settings.... I would encourage all pilots to stop and think before the get in any aircraft and try to identify potential threats and come up with a solutionbefore takeoff. I would also tell single engine pilots to verbally brief their response to engine failure on takeoff or climbout in the same way multiengine and airline pilots brief a takeoff emergency. Also; you should know how your aircraft and its instruments work very intimately. Had I been more familiar with the systems and their limitations; this incident might have been avoided. Finally; I was glad I didn't cut any corners or skip anything. Knowing my corrective lenses were on; I had a briefing on file with FSS; I had preflighted the plane thoroughly (including documents were on board); and the seatbelt and helmet strap were on tight; I was able to focus on the landing; and I was not afraid of certificate action or civil penalties afterward.

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Original NASA ASRS Text

Title: Electronic Speed Controller on the electric motor of an Experimental light sport aircraft failed inflight and the pilot landed on a highway without incident.

Narrative: I preflighted...an experimental [electrically powered] light sport plane.... As part of the preflight; I confirmed the charge was at least 97% in accordance with established procedures. Before departure; I checked the weather online and called FSS to get an abbreviated briefing; including a check of TFRs and NOTAMs. I boarded; completed the checklist; checked the controls and electrical system and departed.... Just before departure; the timer on the aircraft panel said approximately 3:40 elapsed and zero RPM voltage was 73.84v. I departed...using around 95% throttle with at least 24 KW/h for a power setting and the takeoff roll was normal. After liftoff; around midfield...; I reduced power to 22KW/h for the climb. I turned left crosswind...at around 300 to 400 feet above ground level still climbing. I had planned on climbing to an altitude of around 2;000 feet (500 to 600 feet AGL) and orbiting over the quarry and empty field south of the...freeway in compliance with the special airworthiness certificate and operating limitations of the aircraft. After turning left downwind (westbound)...at around 1;800-1;900 feet MSL; I heard a pop similar to the sound of a circuit breaker and the motor lost all power. Before this happened; the motor was still using 22KW/h; no components; ESC (Electronic Speed Controller); Motor; or Battery had shown any unusual temperatures and the timer read 5:06. I began to troubleshoot and glide while continuing the left turn toward the south; over the rock pit. I tried the throttle through its entire range of motion several times; the silver cutoff switch on the left panel; and the key on the right side of the panel. Nothing solved the problem so I pulled the emergency cutoff jumper. At this time I declared an emergency on the...UNICOM and stated I had lost all power and would be landing on the road.... I chose this location as I was too high to land on the flat gravel on the mining property and didn't want to be stuck behind a fence. I ignored the grass south of the [freeway] because I didn't think I could turn around and land before running out of altitude. I was too far to make it to the airport runway. I was nose down; gliding around 75KPH; headed eastbound. As I descended; I realized I was headed for a traffic light support pole and rather than stall the plane; I glided over the traffic lights on the west side of the intersection; and under the traffic lights on the east side. I landed; checked that traffic behind me had stopped and secured the BRS safety pin and shut down the remaining equipment.... City Police arrived in less than a minute and helped stop traffic and push the plane into a side road. By this time a truck from the airport had already arrived and the police helped clear traffic while we towed the aircraft to the airport. There were no injuries; no damage to the aircraft and no damage to persons or property on the ground.After the plane was back in the hangar; the A&P/IA in charge of maintenance arrived and did some basic troubleshooting. He determined the ESC was the problem. A test run of the motor resulted in sparks from the ESC and the same snap noise I had heard in flight. The cover of this component was removed and we determined that at least one of the...power transistors onboard had catastrophically failed.Even though things turned out OK; I was complacent. I knew the aircraft was experimental; but because others had flown it successfully; I was caught somewhat off-guard by the sudden engine failure. In addition; I found out the day after the incident that the temperature gauge for the ESC was not really functional; even though it appeared to be. This functionality is coming in the next software update for the glass panel. Had I known this I would have either not flown or been more wary and alert at high power settings.... I would encourage all pilots to stop and think before the get in any aircraft and try to identify potential threats and come up with a solutionbefore takeoff. I would also tell single engine pilots to verbally brief their response to engine failure on takeoff or climbout in the same way multiengine and airline pilots brief a takeoff emergency. Also; you should know how your aircraft and its instruments work very intimately. Had I been more familiar with the systems and their limitations; this incident might have been avoided. Finally; I was glad I didn't cut any corners or skip anything. Knowing my corrective lenses were on; I had a briefing on file with FSS; I had preflighted the plane thoroughly (including documents were on board); and the seatbelt and helmet strap were on tight; I was able to focus on the landing; and I was not afraid of certificate action or civil penalties afterward.

Data retrieved from NASA's ASRS site as of July 2013 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.