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Pilot reported that the voltage regulator continued to show large oscillations mid-flight despite multiple efforts to isolate and solve the problem.
| Attributes | |
| ACN | 1759110 |
| Time | |
| Date | 202008 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | ZZZ.ARTCC |
| State Reference | US |
| Environment | |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | Skyhawk 172/Cutlass 172 |
| Operating Under FAR Part | Part 91 |
| Flight Phase | Cruise |
| Route In Use | Direct |
| Component | |
| Aircraft Component | DC Regulator |
| Person 1 | |
| Function | Single Pilot |
| Qualification | Flight Crew Commercial Flight Crew Multiengine Flight Crew Instrument Flight Crew Flight Instructor |
| Experience | Flight Crew Last 90 Days 25 Flight Crew Total 3400 Flight Crew Type 1515 |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Inflight Event / Encounter Weather / Turbulence |
Narrative:
Enroute ZZZ1 to ZZZ approximately 1.5 hours into flight in MVFR I began to get wildly oscillating readings from the voltage regulator ranging from 16.1v tp battery discharge (~12.4v). Resetting the alternator had no effect and voltage oscillations continued. I shut down all avionics except the transponder to conserve the battery and landed uneventfully at ZZZ. An a&P was located who inspected the electrical wiring (nothing adverse found); tested the alternator (tested ok); and cleaned the contacts at the voltage regulator. A test flight was made without incident. The following day I left ZZZ for ZZZ2 in MVFR (wildfire smoke) and at the 1.5 hour mark the voltage readings began the same wild oscillation as the day before. I shut down all avionics except the transponder and landed without incident at ZZZ3 where the voltage regulator contacts were again cleaned. A 3/4 power run up showed proper voltage (14.2v) and no oscillation. I continued the flight to ZZZ2 and after about 45 minutes the voltage oscillation returned. All avionics were shut down except the transponder. I fell back on the gyroscopic instruments; compass; and the ipad with foreflight to safely navigate. Radios were turned back on for ZZZ2 and the flight completed. During the last 20 minutes of the flight with the avionics all back on there was no voltage oscillation. Inspection of the regulator (zeftronics R15VOO rev a) after shutdown shows no obvious defects but the regulator is obviously failing and a replacement regulator has been ordered.lessons learned:-IFR partial panel skills should be kept current; even for VFR/MVFR flights.-MVFR/IFR flights should always have an independent navigation backup such as a garmin or foreflight/stratus that can provide reliable navigation and weather information should the aircraft electrical system fail. This is particularly critical over mountainous terrain where landing options are more limited. -Just because an a&P says something is fixed; don't bet the farm on it. I altered the route to ensure that I was never more than 30 minutes (I estimated I had this much time partial panel with a discharging battery) from an airfield.-always know exactly how much draw every item in your panel has and what your total battery capacity is.
Original NASA ASRS Text
Title: Pilot reported that the voltage regulator continued to show large oscillations mid-flight despite multiple efforts to isolate and solve the problem.
Narrative: Enroute ZZZ1 to ZZZ approximately 1.5 hours into flight in MVFR I began to get wildly oscillating readings from the voltage regulator ranging from 16.1v tp battery discharge (~12.4v). Resetting the alternator had no effect and voltage oscillations continued. I shut down all avionics except the transponder to conserve the battery and landed uneventfully at ZZZ. An A&P was located who inspected the electrical wiring (nothing adverse found); tested the alternator (tested OK); and cleaned the contacts at the voltage regulator. A test flight was made without incident. The following day I left ZZZ for ZZZ2 in MVFR (wildfire smoke) and at the 1.5 hour mark the voltage readings began the same wild oscillation as the day before. I shut down all avionics except the transponder and landed without incident at ZZZ3 where the voltage regulator contacts were again cleaned. A 3/4 power run up showed proper voltage (14.2v) and no oscillation. I continued the flight to ZZZ2 and after about 45 minutes the voltage oscillation returned. All avionics were shut down except the transponder. I fell back on the gyroscopic instruments; compass; and the IPad with Foreflight to safely navigate. Radios were turned back on for ZZZ2 and the flight completed. During the last 20 minutes of the flight with the avionics all back on there was no voltage oscillation. Inspection of the regulator (Zeftronics R15VOO Rev A) after shutdown shows no obvious defects but the regulator is obviously failing and a replacement regulator has been ordered.Lessons learned:-IFR partial panel skills should be kept current; even for VFR/MVFR flights.-MVFR/IFR flights should always have an independent navigation backup such as a Garmin or Foreflight/Stratus that can provide reliable navigation and weather information should the aircraft electrical system fail. This is particularly critical over mountainous terrain where landing options are more limited. -Just because an A&P says something is fixed; don't bet the farm on it. I altered the route to ensure that I was never more than 30 minutes (I estimated I had this much time partial panel with a discharging battery) from an airfield.-always know exactly how much draw every item in your panel has and what your total battery capacity is.
Data retrieved from NASA's ASRS site 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.