Date: 201212
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Night
Aircraft: Cessna 152
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Personal
Flight phase: Cruise
Airspace: Class E ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: AC Generator/Alternator
Component problem: Failed
Reporter organization: Personal
Reporter function: Pilot Flying; Single Pilot
Reporter qualification: Flight Crew Private
Human factors: Training / Qualification; Situational Awareness; Distraction; Confusion; Communication Breakdown; Troubleshooting; Workload
Anomaly: Aircraft Equipment Problem Critical
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Diverted; Flight Crew Landed in Emergency Condition; Flight Crew Took Evasive Action; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Departed with VFR flight following; intended departure to the northwest. The departure was uneventful. Approach vectored me west over an interstate highway; at which point I canceled VFR flight following. I did not want to fly over the swamp area; and was clear of all Class B airspace and any approach areas into surround airports. After a brief cruise northbound over an interstate the aircraft began to act peculiar. I was setting up the aircraft to be prepared for night flight by turning on the cabin lights to an appropriate setting and noticed they would steadily dim and brighten. I also began to notice a very faint thumping sound in my headset that sounded similar to strobe lights being activated. After another twenty minutes of flight the noise in my headset persisted and the lights continued to dim and brighten. Curious as to the noise; I shut of the strobe lights to the aircraft; and the noise persisted. Upon turning those back on a very loud screeching noise pierced the headset. At this point I had become aware something odd was occurring. I monitored the ammeter and the low voltage light; but neither showed any signs of failure. No circuit breaks had been popped at this time. Determined to figure out the problem before descending and landing; I flew more west than desired of course to stay above known airports. The problems continued to get worse. The VOR receiver moved erratically; the noise continued in my headset and the lights continued to dim and brighten in the cockpit. I began to shut off equipment; not thinking I had yet had an electrical failure. I shut off my COM1; intercom in the aircraft; aircraft strobe lights (not required for night) and aircraft cockpit lighting. I opened up my airports facilities directory and began looking at nearby airports information.When arriving over the airport many things began to fail. My handheld weather radar began to run off of battery power; all cockpit lights failed when I tried to turn them on; the navigation lights on the wings began to dim and the noise continued to become louder when I turned on my COM1. I quickly made a call to Approach; attempting to see if I had a radio failure. I listened to the frequency on a handheld radio; and even attempted to call Approach using that device. I received no transmission back or any other indication of a successful transmission.I decided to initiate a decent into the airport. I was near the airfield as I could identify the city and lakes that would have been near the airfield; however I could not positively identify the airport. However; I detected the beacon for a known airport to the Northwest. I flew direct to it and used my handheld radio to turn on the lights at the airfield. Making calls on the radio (using a handheld device) I landed Runway 10-28. On the approach however; I did call the runway 'Runway 9.' I had all electrical equipment except transponder turned off at this point. I lowered my flaps as I would normally for an approach; but had only gotten approximately 5 degrees out. I treated this as a 'no-flaps' landing; and exited to the right of the runway on the first available taxiway. At this point I called the aircraft owner; my flight instructor and my father. I was given guidance to cross over to the north ramp area where I tied down the aircraft in front of the terminal. I spoke with my instructor and the aircraft owner and explained what happened. I also got a call from a man who works with the flight school explaining the FAA wanted to confirm everything was fine- no damage to myself; the airport or any airplanes. The FAA recommended I use VFR flight plans for future flights and indicated (as I had thought) that no laws were broken and no lives were jeopardized in my flight. I left a note for the airport facility on the dashboard of the aircraft and spent the night in a nearby hotel. The next day I met the airport manager and local mechanic. The aircraft owner flew down; replaced the alternator and we flew the aircraft back with no further problems.




Synopsis: A Cessna 150's alternator failed gradually and insidiously on a night VMC flight so after recognizing the problem the pilot landed at an airport en route.