Narrative:

Flying into the D.C. Special flight rules area (sfra) I noticed that my aircraft was showing a slight discharge on the ammeter. I had all aircraft systems until the time I started to contact potomac approach to pick up my special flight rules squawk. I could hear another aircraft (cessna) attempting to contact potomac as well with no response. At this time I lost my enroute navigation equipment (moving map) and my engine monitor.I contacted the other aircraft to see if potomac had answered them and they answered with a negative reply. We communicated a few more times and then the cessna tried potomac again and received his squawk. I tried immediately after with no response and tried again where I was answered and given my squawk to enter the sfra. I told potomac I was having radio issues and was looking for clearance direct to a nearby airport. I was given this clearance and focused on rebooting my navigation system and put backup frequencies into my other radio. I tried my other radio and received a piercing noise and my lights went dim inside the aircraft so I decided to turn off unnecessary equipment.enroute; I heard a break of my call sign and the words 'airport'. I understood there was an airport close by so I elected to do a 360 degree turn. During the turn I was able to hear instructions on landing at the airport. I acknowledged but was unsure if my radio call went out. I declared an emergency while in my 360 degree turn because I felt that my radios and equipment were not going to last much longer and I wanted to conserve battery power for my electrical gear for landing. I was able to hear potomac give a few radio calls to include a number to contact.I landed at the airport uneventfully and called the FAA where I was told that secret service agents wanted to debrief. I also called the FAA specialist and told him my story. I was debriefed by both the secret service and FAA with the understanding that the circumstances I encountered were of an emergency nature and no further outcome would be pursued. I would state that the contributing factors to the incident were caused by the loss of electrical power while entering the sfra. I also would acknowledge the difficulty of contacting potomac. It is undetermined whether my radios impeded my contact but the fact that I was able to communicate with the other cessna who was having problems contact ATC confused matters.the change of landing airports at the last minute really caused human performance to degrade and high gains in the cockpit. As a military pilot; we are taught that during a NORDO situation to be predictable which means do what is expected by the parties involved. Changing landing runways was a possible decision that could have made a NORDO situation much worse. Additionally; no services were extended when I declared an emergency. The maintenance outcome appears to be that when the gear was raised; it popped a circuit breaker on the bus that continues to draw amperage while flying and degrading the electrical system and depleting the battery.

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Original NASA ASRS Text

Title: A BE-35 pilot related problems associated with the loss of electrical power and associated communications function with the Washington DC SFRA.

Narrative: Flying into the D.C. special flight rules area (SFRA) I noticed that my aircraft was showing a slight discharge on the ammeter. I had all aircraft systems until the time I started to contact Potomac Approach to pick up my special flight rules squawk. I could hear another aircraft (Cessna) attempting to contact Potomac as well with no response. At this time I lost my enroute navigation equipment (moving map) and my engine monitor.I contacted the other aircraft to see if Potomac had answered them and they answered with a negative reply. We communicated a few more times and then the Cessna tried Potomac again and received his squawk. I tried immediately after with no response and tried again where I was answered and given my squawk to enter the SFRA. I told Potomac I was having radio issues and was looking for clearance direct to a nearby airport. I was given this clearance and focused on rebooting my navigation system and put backup frequencies into my other radio. I tried my other radio and received a piercing noise and my lights went dim inside the aircraft so I decided to turn off unnecessary equipment.Enroute; I heard a break of my call sign and the words 'airport'. I understood there was an airport close by so I elected to do a 360 degree turn. During the turn I was able to hear instructions on landing at the airport. I acknowledged but was unsure if my radio call went out. I declared an emergency while in my 360 degree turn because I felt that my radios and equipment were not going to last much longer and I wanted to conserve battery power for my electrical gear for landing. I was able to hear Potomac give a few radio calls to include a number to contact.I landed at the airport uneventfully and called the FAA where I was told that Secret Service agents wanted to debrief. I also called the FAA Specialist and told him my story. I was debriefed by both the Secret Service and FAA with the understanding that the circumstances I encountered were of an emergency nature and no further outcome would be pursued. I would state that the contributing factors to the incident were caused by the loss of electrical power while entering the SFRA. I also would acknowledge the difficulty of contacting Potomac. It is undetermined whether my radios impeded my contact but the fact that I was able to communicate with the other Cessna who was having problems contact ATC confused matters.The change of landing airports at the last minute really caused human performance to degrade and high gains in the cockpit. As a military pilot; we are taught that during a NORDO situation to be predictable which means do what is expected by the parties involved. Changing landing runways was a possible decision that could have made a NORDO situation much worse. Additionally; no services were extended when I declared an emergency. The maintenance outcome appears to be that when the gear was raised; it popped a circuit breaker on the bus that continues to draw amperage while flying and degrading the electrical system and depleting the battery.

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.