A Maintenance Oriented Podcast For Airplane Owners, Pilots, and Mechanics

Month: November 2019

129 – Air Filters: Don’t Let Your Airplane Suffocate!



Whether your airplane has a “Brackett” brand filter like the first picture, or a “Donaldson” brand filter like the second filter, or another brand like “Challenger” or something else, they all need to be clean and in good condition.

The air your airplane breathes is critically important. Your engine, your vacuum instruments, and even other components, all need to breathe fresh clean air in order to function properly.

Listen to today’s episode to hear about induction filters, vacuum system filters, and even an obscure filter you may not have thought about.

Take a look at what can happen when a Brackett filter is not changed often enough. Upon removal, the foam filter crumbled apart.


Brackett filters have an expiration date on the package… while they work very well when they’re in good condition, they can also fall apart when they are expired. Don’t install an expired filter!

Vacuum systems also need clean filters. Check out this vacuum regulator filter that is covered with dust… this thing has been here for years! Compare this with the new filter that needs to be installed. This filter is sometimes overlooked at the annual inspection. The part number is B-3-5-1. Or, if you buy a Rapco filter, it’s RAB-3-5-1.


The vacuum inlet filter is also an important one to keep clean, so that your vacuum instruments, like the attitude indicator and directional gyro, can breathe nice, clean air. Here’s an example of an old, dirty vacuum inlet filter, compared with a new, clean one:

Clean air filers are vitally important!

Another obscure filter I encountered recently was on an Aerostar 601P. This airplane has a Sandel SN3308 electronic HSI. The internal lamp needs to be changed at regular intervals. Upon removing the unit from the instrument panel, I discovered the fan filter in the bottom of the tray was falling apart. Take a look at the view from under the instrument panel, and how little was left of the foam filter:

The fan pulls air in through the bottom of the instrument tray, for cooling.

It’s a bit of an obscure air filter, but still an important one.

A call to Sandel was very helpful. Although the new filter is a fairly thin, coarse mesh piece of foam, it actually has a part number, and the price was reasonable ($8.) Check it out in the following picture:

The HSI is now breathing clean air again.

So… whether it’s an airplane’s induction filter, a vacuum system filter, an instrument filter, or some other filter, it’s important for all these filters to be clean and in good condition.

Take a look at your filters, and make sure your airplane is breathing nice clean air. Your engine, your vacuum system, and your instruments, will thank you in the form of reliable performance 🙂

Filters discussed in this episode:

Brackett induction filters.

Donaldson induction filters.

Challenger Aviation induction filters.

Vacuum inlet and regulator filters.

Sandel HSI cooling fan filter.

128 – Should I Buy a Twin Cessna or a Beech Baron?

In this week’s episode, we are talking about upgrading to a twin, and some thoughts about choosing between a twin Cessna and a Beech Baron.

Thank you Simon Cail, for your email, and for permission to read the email in this episode.

Simon’s decision was between a Cessna 340 and a Beechcraft Baron 58.

The pictures above are of a Cessna 414 and a Baron 55. But I think they’re close enough for the purposes of this episode.

Listen to the audio for some thoughts about the two types of airplanes, especially from a maintenance perspective.

Simon, I wish you well in your upgrade to a twin… let me know what you decide. And thanks again for your email!

Links and Resources:

American Bonanza Society: https://www.bonanza.org/

Twin Cessna Flyer: https://www.twincessna.org/

Bob Ripley’s maintenance shop in Georgia: http://soaero.com/

Tony Saxton’s twin Cessna shop: https://tas-aviation.com/

“Rig it Right” twin Cessna landing gear rigging instructions: https://www.twincessna.org/OnLineStore.asp?p_num=P016

Baron and Bonanza landing gear inspection checklist and repair guide:http://www.flyabonanza.com/Resources_files/abs%20landing%20gear%20guide%20copy.pdf

127 – No Oil Pressure in a Cessna 150

My friend Matt and I had a plan, and it was going to be an awesome adventure. The crisp, clear morning was as nice as we could hope for on a November day in Virginia. The half hour drive from my house to the small town New Market Airport was absolutely refreshing… exhilarating even.

As I pulled onto the airport drive, I didn’t go far before I was compelled to back up and take a picture of the signs that arrested my attention. “DEAD END STREET” AND “LEARN TO FLY HERE” just did not seem to fit together in my mind. As I think about it, I wish I could replace that top sign with “PATHWAY TO POSSIBILITIES!”

For me, and for my friend Matt, we had far more in mind that day than any dead end street. If our planned adventure came together, we would be flying a little Cessna 150 to Tangier Island (KTGI) and maybe having a crab cake sandwich for lunch. But first, we had to solve a problem… a report of “No oil pressure.”

We struggled to get the “barn doors” open in the old rustic hangar, and the site looked so familiar for these old airports, complete with gravel floor, a motorcycle off to the side, as well as a Cessna 120 and another Cessna 150. I was actually pleasantly surprised when I saw the good condition of the airplane we’d be working on.

We decided to go ahead and start the engine and see if we got any oil pressure within 30 seconds. The engine started nicely and within seconds, we saw the oil pressure needle creeping up… good news indeed. However, after some warm-up time, we noticed the oil pressure needle went back down, and was approaching the red line at the bottom of the gauge. (It had never made it up to the green arc.)

So we shut down, and decided to see if the oil pressure line had any air in it. Thankfully, the gauge was very accessible at the bottom of the pilot instrument panel. After loosening the nut for the oil pressure line behind the gauge, there was not even a drop of oil there. So we attempted to motor the engine with the starter to get the air out of the line.

Now we had another problem… low battery power! The engine wouldn’t even turn over more than a turn or so. Back to troubleshooting, except now in the electrical system.

Matt suspected the alternator was not working, and this proved to be true when we discovered no voltage at the field terminal on the back of the alternator when we turned the master switch on.

Then something jumped out at me… I was standing over on the left side of the engine, and I noticed the whole wiring harness plug was disconnected from the voltage regulator at the firewall. Take a look.

Amazing how well things work when all the wiring is connected properly!

So after charging the battery, we tried again to purge the air out of the oil pressure line. Matt motored the engine with the starter for maybe 30 seconds, and just as he let off the starter, I saw oil seeping out at the gauge connection… success, finally!

This time, after starting, the oil pressure climbed up in the green arc, and stayed there during the runup.

Now, how about Tangier Island? Could we still go?

Nope… I noticed the maintenance records were in the back of the airplane, and the airplane was still in annual… sort of. The main thing is there was some lacking documentation that made it unwise to fly the airplane until it was resolved. Mechanically, I totally would have been confident to go flying in that airplane with Matt. But paperwork-wise, the issue needed to be resolved.

That’s ok… instead of lunch at Tangier Island, Matt and I had breakfast at Dunkin Donuts. And… we’re not giving up on the Tangier Island idea. In fact, after thinking about the whole thing, I did some research, and discovered a young man named Swayne Martin, who gave me even more motivation to visit Tangier Island. He and his brother flew their mom there in a Cessna 172 several years ago as a mother’s day gift! If you’re interested, his post is very interesting.

You may recognize Swayne from his involvement with the Boldmethod online flight training resources. He also has an excellent YouTube channel. I also found out he has gone on to become a first officer with one of the regional airlines. Well done Swayne!

Now back to Tangier Island… Matt and I are not giving up, and I’m confident we’ll still get there one of these days… very possibly in that very Cessna 150 we worked on. And when we do, you’ll hear about it, because it will no-doubt be an excellent adventure for another podcast episode!

It really was a great day, and the sunset view of my neighbor’s field from my back yard, was just as fantastic as the sunrise view on the way to the New Market Airport.

Days like this make me say, “Thank you Lord, it’s good to be alive!”

126 – Magneto Trouble at Higher Altitudes

Corrosion in the towers of a magneto can cause high resistance, and the problem will be magnified as you go up in altitude.

This green corrosion could likely be cleaned up and it may improve some, but it may also indicate a good time to perform either a 500 hour inspection or an overhaul on the magneto.

Pressurized magnetos have an o-ring that seals the connection where the wiring harness attaches to the magneto. I found this one on a twin Cessna last week, while changing one of the magnetos.

Listen to today’s episode to hear about the details of this issue, and some things to think about for optimal magneto performance.

Thankfully, we got the twin Cessna running again, and the owner made 4 flights the very next day!

Have a great week friends!