Here’s the short answer: Worn and contaminated brushes inside the alternator. Check it out:

My theory is that the excessive amount of carbon dust from brush wear was causing a short circuit situation between the brushes, and not allowing the field circuit in the alternator rotor to be properly energized for normal operation.

Here’s a comparison of the old and new brushes:

This story comes from a recent situation on the right engine of this Aerostar aircraft:

Since the alternator has externally removable brushes, it turned out to be a minimally invasive surgery to fix the problem. I cleaned the brush holder and also the slip rings inside the alternator, and after installing new brushes and reassembling everything, the alternator performed flawlessly.

Listen to the audio to hear the full story.

This episode also covers some of the email responses I received last week from some listeners, and here’s one of the highlights:

Glen sent me a photo of he and his dad in front of his Piper Cherokee… I love to see different generations enjoying aviation adventures together!

One more fun fact: Glen’s mom took her private pilot check ride years ago with Glen in the back seat of their Cessna 175 when he was 3 weeks old! What a great story!

Thanks Glen, for sharing some of your story with us!

This episode also covers a recent trip to Charlotte in another Aerostar, and the interesting routing we got from ATC on the way there… definitely some great IFR and ATC lessons to observe and learn from this one!

The Charlotte trip also sparked some conversation about twin engine charging systems, and paralleling issues that can happen… this situation is still in process, and I’ll try to give an update sometime in the future.

Finally, I had the privilege of joining Carl Valeri, Tom Frick, and Bill English on episode 301 “What is Your Most Challenging Approach” of the Stuck Mic AvCast. It was great fun talking about challenging approaches, both instrument and visual approaches.

Here’s a link where you can listen:

I also highly encourage you to check out Carl Valeri’s Aviation Careers Podcast:

http://www.aviationcareerspodcast.com/

You can also find the Aviation Careers Podcast on YouTube.

https://www.youtube.com/@AviationCareersPodcast

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