Narrative:

During the climb we experienced a failure of the left generator. We continued monitoring the electrical system; the left generator was unable to be reset; we reduced unnecessary load. Later in the climb; checking the breakers again we noticed the load bus tie circuit breaker had also popped on the captain's side circuit breaker panel and that the right generator was no longer charging the main battery. We reset the breaker once and the right generator came online; showing a charge to the battery for approximately 10 seconds. Then it popped again; we did not try and reset it a second time. We were operating on the remaining battery power only. We simultaneously began reducing additional electrical load; and tried to contact center. As we were calling center we began experiencing failure of the captain's side instrument panel and the standby attitude indicator. Due to instrument failures on the captain's side; I assumed control of the aircraft from the right seat. Every time we tried to transmit on center frequency we had static feedback; so we assumed radio failure and set our squawk code to 7700; then 7600 and began a descent out of fl 200. We briefly discussed our destination; runway requirements; and continued to try to contact ATC. Out of approximately 17;000 ft; we spoke with another aircraft who relayed our communications to center and asked for vectors for the closest runway over 5;000 ft. At the beginning of our descent we had about 16 volts indicated on the battery. We were eventually given vectors to a nearby airport; and the CTAF frequency. We opted for the ATC suggested airport; being certain that if we tried a return to the departure airport; or any other airport; we would have had zero battery power for navigation and landing. Out of 11;000 ft and after a vector to heading 090 we were able to get a visual on runway 36. We entered an extended left base for runway 36 and announced landing. I asked for a descent and approach checklist and used the speed brakes to slow to gear/flap speed of 200 KTS. We attempted to extend the flaps with no success; we then attempted to extended the gear; which was successful. We made the conclusion on base leg that the remaining battery power was not enough to extend the flaps on the aircraft. Vref for flaps zero came in at (132 KTS) for 13;500 pound landing weight. On final; I transferred the aircraft back to the first officer; so I could have access to the emergency braking handle if needed. He touched down at approximately the 1;000 ft marker; at vref; he called that he had brakes; and continued to apply pressure. However; we quickly realized the brakes were not maintaining pressure anymore; I broke the safety wire of the emergency nitrogen handle and began applying nitrogen pressure during our last approximate 1;500 ft of runway. It was inadequate and we overran the runway. The aircraft traveled down a hillside with no control other than nose wheel steering; which the first officer used to turn the aircraft prior to the tree line. Soon after we turned we came to a stop. Once we were at a complete stop we ordered the passengers to evacuate; which we did out of the main cabin door. I turned the power completely off and grabbed the fire extinguisher. I applied the extinguisher to the right main landing gear and we shoveled wet clay onto both main gear.

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Original NASA ASRS Text

Title: A MU300's left generator and the Bus Tie failed; preventing the battery from charging. An emergency was declared and after the aircraft diverted the brakes failed to stop the aircraft before it exited the runway's end.

Narrative: During the climb we experienced a failure of the left generator. We continued monitoring the electrical system; the left generator was unable to be reset; we reduced unnecessary load. Later in the climb; checking the breakers again we noticed the load bus tie circuit breaker had also popped on the Captain's side CB panel and that the right generator was no longer charging the main battery. We reset the breaker once and the right generator came online; showing a charge to the battery for approximately 10 seconds. Then it popped again; we did not try and reset it a second time. We were operating on the remaining battery power only. We simultaneously began reducing additional electrical load; and tried to contact Center. As we were calling center we began experiencing failure of the Captain's side instrument panel and the standby attitude indicator. Due to instrument failures on the Captain's side; I assumed control of the aircraft from the right seat. Every time we tried to transmit on Center frequency we had static feedback; so we assumed radio failure and set our squawk code to 7700; then 7600 and began a descent out of FL 200. We briefly discussed our destination; runway requirements; and continued to try to contact ATC. Out of approximately 17;000 FT; we spoke with another aircraft who relayed our communications to Center and asked for vectors for the closest runway over 5;000 FT. At the beginning of our descent we had about 16 volts indicated on the battery. We were eventually given vectors to a nearby airport; and the CTAF frequency. We opted for the ATC suggested airport; being certain that if we tried a return to the departure airport; or any other airport; we would have had zero battery power for navigation and landing. Out of 11;000 FT and after a vector to heading 090 we were able to get a visual on Runway 36. We entered an extended left base for Runway 36 and announced landing. I asked for a descent and approach checklist and used the speed brakes to slow to gear/flap speed of 200 KTS. We attempted to extend the flaps with no success; we then attempted to extended the gear; which was successful. We made the conclusion on base leg that the remaining battery power was not enough to extend the flaps on the aircraft. Vref for flaps zero came in at (132 KTS) for 13;500 pound landing weight. On final; I transferred the aircraft back to the First Officer; so I could have access to the emergency braking handle if needed. He touched down at approximately the 1;000 FT marker; at Vref; he called that he had brakes; and continued to apply pressure. However; we quickly realized the brakes were not maintaining pressure anymore; I broke the safety wire of the emergency nitrogen handle and began applying nitrogen pressure during our last approximate 1;500 FT of runway. It was inadequate and we overran the runway. The aircraft traveled down a hillside with no control other than nose wheel steering; which the First Officer used to turn the aircraft prior to the tree line. Soon after we turned we came to a stop. Once we were at a complete stop we ordered the passengers to evacuate; which we did out of the main cabin door. I turned the power completely off and grabbed the fire extinguisher. I applied the extinguisher to the right main landing gear and we shoveled wet clay onto both main gear.

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.