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Training and Safety Tip: Alternator failure

Editor's note: This article was updated May 24.

A beautiful, clear morning sky stretched from Gallup, New Mexico, to Oshkosh, Wisconsin. It was my second flight to EAA AirVenture Oshkosh, and I had a good idea what to expect.

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Photo by Mike Fizer.

My wife, daughter, and I took off before dawn. Our flight path took us north of Albuquerque and just south of Santa Fe. The landscape was beautiful in the early morning light—something my passengers unfortunately could not enjoy because they were asleep. Oh well. Checking the engine gauges as I had been taught to do, I noticed the needle on the voltmeter was all the way to the left side of the gauge. Thus, I had a problem. I had been excited about planning the trip for an early arrival to find a convenient camping location, but suddenly I had to unexpectedly make an important decision just an hour into our flight.

By then, it was about 6:30 a.m., and I knew that I could get the voltmeter repaired in Albuquerque. But the repair shop probably would not open until 8 a.m., which meant that at best we would probably not be back in the air bound for Oshkosh before noon. My VFR flight plan’s first leg had us land at Dodge City, Kansas. I knew this was not a crisis—I could turn off all unnecessary electrical equipment until I got within 10 miles of the Dodge City airport. There, we could have brunch while the airplane was being repaired. I thus decided to fly that leg of the trip navigating by reference to charted visual landmarks. As we approached Dodge City, I contacted the control tower and informed them that the airplane was operating on battery power. By mid-morning, the airplane was signed off as airworthy, and we were on our way to Oshkosh.

The point is that the airplane's magnetos provide the electricity that powers engine ignition, while the rest of the aircraft's electrical system runs independently on power provided by the battery and/or alternator. Dual magnetos, each able to mechanically generate all of the electricity that the engine requires, are a safety feature common to most certified piston airplanes (electronic ignition systems are gaining popularity—and FAA approval—replacing one or both magnetos). Pilots need to be knowledgeable about their airplane’s electrical system and how to slow or terminate electrical equipment use, such as communication and navigation equipment, and various aircraft lights.

Was this situation an emergency? No, I don’t think so. We never experienced an elevated risk status. This was an example of making do with “abnormal procedures” aided by amazing VFR weather conditions.

Important in this real-world scenario, as in any situation outside “normal operations,” is not to panic. Always consider your options in a logical, professional manner. Know the airplane you fly. Declare an emergency if the safe completion of a flight is in question. 

Ed Helmick
Ed Helmick has been a flight instructor since 1988. He formerly managed a flight school in Spanish Fork, Utah, as well as schools in Scottsdale, Arizona; and Honolulu, Hawaii.
Topics: Training and Safety, Flight Instructor, Aircraft Systems
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