Date: 201510
Local time of day: 1201-1800
Location: ERI.Airport, PA
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: Cardinal 177/177RG
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Personal
Flight phase: Cruise
Airspace: Class E ERI
ATC / advisory: Tower ERI
Aircraft component: AC Generator/Alternator
Component problem: Malfunctioning
Reporter organization: Personal
Reporter function: Single Pilot
Reporter qualification: Flight Crew Instrument; Flight Crew Private
Human factors: Situational Awareness; Troubleshooting; Time Pressure; Confusion
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Landed As Precaution; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: While on an IFR flight to ERI in VMC; I experienced a partial alternator failure. The ammeter indicated that the battery was discharging. I attempted to reset the alternator by cycling the master switch; but this was unsuccessful. I shut down the autopilot and COM2 to shed some of the load on the battery. I notified Erie Approach of the problem and told them that; if I lost COM; I would proceed inbound VFR and asked them; if that happened; to tell the Erie Tower that I would be looking for the light signals to land. It seemed better to notify them of my intentions and have a clear; shared plan instead of relying on our mutual understanding (and memory) of the IFR lost COM procedures. Erie was reporting OVC034; but the visibility was excellent and I could see that the sky was clear just north of the airport. Maintaining VFR was not in doubt. The situation seemed to worry the controllers more than it worried me. They asked how many people on board (one) and how much remaining fuel (32 gallons). I was cruising at 5;000 ft. MSL. ATC asked for my flight conditions; which were VMC/SKC. They told me to descend at pilot's discretions to 3;000; which I did. They then asked me if I wanted to cancel if I lost COM or cancel now. Since it was VMC; I cancelled now. I was told to enter right downwind for runway 24. I thought that this was a mistake; but expected Erie Tower to correct it. Erie Approach handed me off to Erie Tower. Tower cleared me to land on runway 24.When I was 14 miles out; Erie tower delayed an arriving airliner because of an inbound Cessna with an alternator failure (me). He wanted to get the Cessna on the ground. This seemed like an overreaction to me. Tower asked me to 'keep my speed up;' and I agreed to. Shortly thereafter; another airliner arrived. He informed them that they were #3 following a Cessna with a failed alternator and another airliner. I felt bad that he was delaying two airliners for my relatively minor technical problem. This caused me more stress and distraction than the alternator failure did. I thought about offering to wait for the airliners to land; but did not. In my experience; ATC has reasons for what they do and they don't always appreciate uninformed offers to help. I figured that he wanted me out of the way.I had departed ZZZ from runway 7. When I arrived ERI; I was assuming that I would land in the same general direction; on runway 6; even though the METAR said runway 24 in use and I had been told to enter right downwind for runway 24. I was also distracted by the delayed airliners and the alternator failure and I was eager to be out of his way; so I was proceeding straight in (runway 6). When I was several miles out; the tower asked me if I could make a short approach. I made an uneventful short approach and landed; quickly exiting the runway at taxiway A3. After the flight; I called my flight instructor to debrief about my handling of the problem and especially about how distracting it was to have even a small technical issue.Lessons:1. I still think that telling ATC about my situations and my plans was a good idea.2. Fuel on board? I should have answered in hours not gallons. '32 gallons remaining' sounds more ominous than 'four hours of fuel remaining.'3. I should occasionally review lost COM procedures.4. I should have stopped and thought when they told me right downwind instead of thinking that they were mistaken.5. Don't assume that you will be landing in the same direction that you took off from 100 nm away.6. I need to better familiarize myself with the electrical system in the plane. Which half of the master switch cycles the alternator? The circuit breakers are not clearly labeled. This was distracting and caused me to inadvertently shut down my transponder for a short while; maybe more than once.7. I was glad that this problem did not happen at night in IMC.




Synopsis: A general aviation pilot reported a malfunctioning alternator while inflight. He requested assistance from ATC and received a traffic priority in order to expedite his arrival at the destination airport where an uneventful landing was accomplished.