Narrative:

On climbout; I was handed over to departure control by tower. Departure reported radar contact. I engaged the autopilot after 1;000 ft and leveled off at 1;500 ft. At this point of the flight; all systems appeared to function normal. About 10 miles east of ZZZ1; ATC asked me if I was receiving a reply light on my transponder. I verified the reply light and altitude back to ATC. ATC then pointed out company traffic in opposite direction at 2;000 ft. I saw the traffic and reported back to ATC. I then noticed that my autopilot had disengaged. I tried a couple of attempts to engage the autopilot but only got an audible disengage tone. I proceeded to hand fly the remainder of the flight to ZZZ2. I double-checked the aircraft logs to see if there were prior write-ups about the autopilot or transponder and found none. There was an open MEL item about night panel lighting on the pilot's left-hand side. ATC then informed me that the transponder problem was probably due to their equipment. Proceeded to turn direct to ZZZ2; which is uncontrolled. Within 5-7 miles of ZZZ2; approach instructed me to squawk VFR 1200 and to contact ZZZ2 CTAF. I proceeded to descend to 1;000 ft and self announce my position and intention to enter a left base to runway xx. After reaching 1;000 ft; I began my in-range flows; which includes a power reduction and setting flaps 15 degrees. I heard traffic reporting on CTAF about departing runway xx. I looked for the traffic; but did not see any aircraft. On a 3 miles left base; I selected gear down; mixture full; props 2;450 RPM. I thought I saw 3 green with no red gear unsafe lights and started the before landing checklist. I looked for traffic on the runway and saw none. At 600 ft; I selected flaps 30 degrees and turned final. The wind conditions were gusty and variable directions below 1;000 ft based on the windsock. I overshot final a little bit but was able to correct above 300 ft. I selected full flaps 45 degrees at 300 ft. The ground speed appeared to be too fast for a safe landing; so I initiated a go-around. I selected flaps 15 degrees and when I went to retract the gear handle; I noticed there were no lights illuminated even though the gear handle was positively in the down and locked position. During the landing phase; there was no gear warning horn audible or red gear unsafe lights visible. I climbed to 1;500 ft to troubleshoot the problem. I tried testing the gear system by pressing the annunciator lights to see if any lights would appear or any horns activated. I saw and heard none even with my headsets off. I considered flying back to ZZZ1 to use the emergency gear extension procedure. I tried extending the flaps beyond 15 degrees to get a warning horn but the flap indicator would not move. At this point; I thought that there might be an electrical problem. The voltmeter was showing a system voltage of 10-12 volts; normal voltage should be 28 volts. I thought possibly the starter system could be draining power from the battery. So I checked the starter warning lights which were off. I did not see any alternator or low voltage lights illuminate during the entire flight and they remained off. During the preflight; run-up; and postflight; these lights appeared to be working normal as well as the gear warning system. I decided against returning to ZZZ1 due to insufficient electrical power. The nav/comm appeared to be working normal at this point; but I didn't know how much longer they would function properly. I tried to restore electrical power by recycling the alternator switches (which happens to be the recommended procedure for restoring an over voltage relay that has taken the alternators off-line). Shortly after this; system voltage began to rise to normal and the gear cycled to the down and locked position. I was able to get flap extension. I was confident that the gear was down and locked and flaps were operating normally. I proceeded to land normally in ZZZ2. After engine shutdown; I noticed som

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Original NASA ASRS Text

Title: C402 pilot reports insidious electrical failure that nearly results in a gear up landing but does result in propeller damage during go-around.

Narrative: On climbout; I was handed over to Departure Control by Tower. Departure reported radar contact. I engaged the autopilot after 1;000 FT and leveled off at 1;500 FT. At this point of the flight; all systems appeared to function normal. About 10 miles east of ZZZ1; ATC asked me if I was receiving a reply light on my transponder. I verified the reply light and altitude back to ATC. ATC then pointed out company traffic in opposite direction at 2;000 FT. I saw the traffic and reported back to ATC. I then noticed that my autopilot had disengaged. I tried a couple of attempts to engage the autopilot but only got an audible disengage tone. I proceeded to hand fly the remainder of the flight to ZZZ2. I double-checked the aircraft logs to see if there were prior write-ups about the autopilot or transponder and found none. There was an open MEL item about night panel lighting on the Pilot's left-hand side. ATC then informed me that the transponder problem was probably due to their equipment. Proceeded to turn direct to ZZZ2; which is uncontrolled. Within 5-7 miles of ZZZ2; Approach instructed me to squawk VFR 1200 and to contact ZZZ2 CTAF. I proceeded to descend to 1;000 FT and self announce my position and intention to enter a left base to Runway XX. After reaching 1;000 FT; I began my in-range flows; which includes a power reduction and setting flaps 15 degrees. I heard traffic reporting on CTAF about departing Runway XX. I looked for the traffic; but did not see any aircraft. On a 3 miles left base; I selected gear down; mixture full; props 2;450 RPM. I thought I saw 3 green with no red gear unsafe lights and started the before landing checklist. I looked for traffic on the runway and saw none. At 600 FT; I selected flaps 30 degrees and turned final. The wind conditions were gusty and variable directions below 1;000 FT based on the windsock. I overshot final a little bit but was able to correct above 300 FT. I selected full flaps 45 degrees at 300 FT. The ground speed appeared to be too fast for a safe landing; so I initiated a go-around. I selected flaps 15 degrees and when I went to retract the gear handle; I noticed there were no lights illuminated even though the gear handle was positively in the down and locked position. During the landing phase; there was no gear warning horn audible or red gear unsafe lights visible. I climbed to 1;500 FT to troubleshoot the problem. I tried testing the gear system by pressing the annunciator lights to see if any lights would appear or any horns activated. I saw and heard none even with my headsets off. I considered flying back to ZZZ1 to use the emergency gear extension procedure. I tried extending the flaps beyond 15 degrees to get a warning horn but the flap indicator would not move. At this point; I thought that there might be an electrical problem. The voltmeter was showing a system voltage of 10-12 volts; normal voltage should be 28 volts. I thought possibly the starter system could be draining power from the battery. So I checked the starter warning lights which were off. I did not see any alternator or low voltage lights illuminate during the entire flight and they remained off. During the preflight; run-up; and postflight; these lights appeared to be working normal as well as the gear warning system. I decided against returning to ZZZ1 due to insufficient electrical power. The Nav/Comm appeared to be working normal at this point; but I didn't know how much longer they would function properly. I tried to restore electrical power by recycling the alternator switches (which happens to be the recommended procedure for restoring an over voltage relay that has taken the alternators off-line). Shortly after this; system voltage began to rise to normal and the gear cycled to the down and locked position. I was able to get flap extension. I was confident that the gear was down and locked and flaps were operating normally. I proceeded to land normally in ZZZ2. After engine shutdown; I noticed som

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.