Narrative:

I was on an IFR flight plan direct to [destination] in cruise at 8;000 ft. The autopilot stopped operating. While I was troubleshooting the problem; I noticed that the battery charge was low and falling rapidly. I attempted to notify approach of the problem and believe that they understood that we had lost our alternator and were about to lose communications. Then we lost communications as our transmitter was too weak. I started turning off avionics and other electrical systems in an attempt to save battery power while troubleshooting the alternator. It did not come back online and I turned off the batter to conserve what power remained. I attempted to make radio contact with an onboard hand-held radio; but either its transmissions were too weak or its battery was too low to transmit effectively. Despite repeated attempts I was never able to use it to communicate. I had a hand-held GPS; an ipad with foreflight installed and a stratus ads-B receiver to use for navigation and weather avoidance.... I determined that to continue along our flight planned route would be hazardous due to thunderstorm avoidance; possible frozen pitot tube and potential conflict with other aircraft around without a transponder. During a break in the IFR conditions I observed clear air to the southeast and turned towards it in order to stay out of the clouds and avoid a frozen pitot tube. I decided to continue in the clear air to the southeast and while I had an opening to descend to a VFR altitude below the cloud bases. Once I got to the east of the line of storms I turned south in excellent VFR conditions paralleling the line of storms. Periodically I flipped the master switch on momentarily to check the charge on the battery. For some reason it seemed to be gaining a little bit of charge. The more time passed; the more charge returned. Because of this I determined that if I continued on to [destination] there was a reasonable chance that the battery would have sufficient power to lower the gear and thus an emergency extension procedure might not be required. I was concerned with lost ATC contact -- they might be worried that we had crashed and/or that they might be clearing traffic anticipating our overflight. With the increased charge on the battery; I decided to try the radio and was able to make contact briefly. I stated our situation; cancelled IFR and explained that while we were likely to lose contact again we were going to continue on to our destination. The controller was very helpful and asked if we required assistance and mentioned that [an alternate field] was to the east and asked if we wanted land there. Given the VFR flight conditions; the fact that we could navigate VFR around the weather and any airspace; and finally the possible avoidance of an emergency gear extension; I declined to land [there]. I lost contact as the battery charge dropped again. I continued VFR to the southeast around the line of storms. A few minutes out; I slowed the aircraft; turned on the battery and had enough charge to extend the gear. With all other electrical off other than the rotating beacon; one navigation comm and the transponder squawking VFR; I made radio calls for the pattern and performed a no flaps landing. After I landed I telephoned the FSS in order to make sure that no one was concerned about or looking for us. They confirmed that they had received our IFR cancellation; but were nonetheless glad to know that we arrived safely. In reviewing my decision making for this situation I believe that the decision to get into VFR flight conditions was a good one as well as to use these conditions to navigate around the storms. I might second guess my decision not to land at [an en route alternate]. Although I have practiced the emergency gear extension procedure in the aircraft; if there was a reasonable chance to avoid having to take that step then I believe that given the VFR conditions for continuing the flight I probably made the right decision.

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Original NASA ASRS Text

Title: C210 pilot on an IFR flight plan with only partial electrical power and intermittent communications due to a faulty alternator; maintained VFR and navigated via handheld GPS and iPad to the destination airport.

Narrative: I was on an IFR flight plan direct to [destination] in cruise at 8;000 FT. The autopilot stopped operating. While I was troubleshooting the problem; I noticed that the battery charge was low and falling rapidly. I attempted to notify Approach of the problem and believe that they understood that we had lost our alternator and were about to lose communications. Then we lost communications as our transmitter was too weak. I started turning off avionics and other electrical systems in an attempt to save battery power while troubleshooting the alternator. It did not come back online and I turned off the batter to conserve what power remained. I attempted to make radio contact with an onboard hand-held radio; but either its transmissions were too weak or its battery was too low to transmit effectively. Despite repeated attempts I was never able to use it to communicate. I had a hand-held GPS; an iPad with Foreflight installed and a Stratus ADS-B receiver to use for navigation and weather avoidance.... I determined that to continue along our flight planned route would be hazardous due to thunderstorm avoidance; possible frozen pitot tube and potential conflict with other aircraft around without a transponder. During a break in the IFR conditions I observed clear air to the southeast and turned towards it in order to stay out of the clouds and avoid a frozen pitot tube. I decided to continue in the clear air to the southeast and while I had an opening to descend to a VFR altitude below the cloud bases. Once I got to the east of the line of storms I turned south in excellent VFR conditions paralleling the line of storms. Periodically I flipped the master switch on momentarily to check the charge on the battery. For some reason it seemed to be gaining a little bit of charge. The more time passed; the more charge returned. Because of this I determined that if I continued on to [destination] there was a reasonable chance that the battery would have sufficient power to lower the gear and thus an emergency extension procedure might not be required. I was concerned with lost ATC contact -- they might be worried that we had crashed and/or that they might be clearing traffic anticipating our overflight. With the increased charge on the battery; I decided to try the radio and was able to make contact briefly. I stated our situation; cancelled IFR and explained that while we were likely to lose contact again we were going to continue on to our destination. The Controller was very helpful and asked if we required assistance and mentioned that [an alternate field] was to the east and asked if we wanted land there. Given the VFR flight conditions; the fact that we could navigate VFR around the weather and any airspace; and finally the possible avoidance of an emergency gear extension; I declined to land [there]. I lost contact as the battery charge dropped again. I continued VFR to the southeast around the line of storms. A few minutes out; I slowed the aircraft; turned on the battery and had enough charge to extend the gear. With all other electrical off other than the rotating beacon; one NAV Comm and the transponder squawking VFR; I made radio calls for the pattern and performed a no flaps landing. After I landed I telephoned the FSS in order to make sure that no one was concerned about or looking for us. They confirmed that they had received our IFR cancellation; but were nonetheless glad to know that we arrived safely. In reviewing my decision making for this situation I believe that the decision to get into VFR flight conditions was a good one as well as to use these conditions to navigate around the storms. I might second guess my decision not to land at [an en route alternate]. Although I have practiced the emergency gear extension procedure in the aircraft; if there was a reasonable chance to avoid having to take that step then I believe that given the VFR conditions for continuing the flight I probably made the right decision.

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.