Mag Check Fail
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- เผยแพร่เมื่อ 28 ส.ค. 2024
- Thanks for joining me on this planned flight. Spoiler Alert, I'm about to find out that I am not flying today.
Before every flight, a pilot checks the weather, confirms he or she is in good health, and checks the plane for structural integrity. After the start, it's time to check the various systems in the airplane, including the electrical system that powers the spark plugs. It's one of those things we assume always works. Today is a different story for me. Guess that's why we check it.
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Blue Skies & Tailwinds.
Wow I will be extra careful to watch EGT during the mag check from now on. Thanks for the great video Mark!
The extra data point really helps diagnose issues. The other thing that may be helpful is to figure out which mag (L or R) goes to top or bottom spark plug. And generally, each mag does half the top plugs and half the bottom. Knowing which plug can save maintenance time/dollars by pinpointing the correct plug. Not a big deal, but every little bit helps. In a Cirrus, it's much easier to get to the top plugs as well.
Thanks for sharing this. I've not seen anyone run through a bad plug or magneto in a video, so this was very educational.
Glad it was helpful!.
“Did you have fun?” haha. Great video. Lesson learned…
I thought it was funny too. It added a light moment to a disappointing outcome.
Great explanation. This happened to me yesterday on my second ever flight training, and we called it. I saw it as a valuable lesson for a new student pilot!
It's one of those things that may never come up, but when it does, so many pilots I know focus on the RPM rather than the EGT's and pinpointing which cylinder and why. All the best to you in your training Tonya.
Great catch! Thanks for sharing what a mag issue looks like.
You're welcome. Thanks for the comment.
Great video, makes me feel good to know how serious you are about safety. I’m sure M and the kids appreciate it too. You need to make it back to Stl this summer. I’m sure Zach would love to see you fly again .
Thanks Brian.
Checklists RULE! :-) Wow, that's a nice panel! :-)
Great explanation!
Thank you for commenting. Glad it helped.
Thank you for this video. I experience a mag check fail yesterday as well. Was doing the run up in my 1946 Ercoupe after installing a new carburator and had my engine RPM drop to 1400 on the left. It ran fine on the right and both but dropped every time I went to left. Now with it being a 1946 I don't have EGT gauges so I will have to pull the plugs and look at them all. I'm hoping it is just some build up. My plane doesn't have mixture control so maybe it is just fouled or some gas stuck there.
Let me know what you find. I'm guessing a plug, but who knows. You can take off the cowling, start the engine and run it for a couple of minutes on the left position. Then shut it down and feel if one cylinder is cold or much colder than the rest. Remember, you have two plugs, so only run on the rough one. Then trace the spark plug wire from the bad mag to that cylinder. As you probably know, the OFF, L, and R positions are all doing the same thing. Grounding or turning off both, or individual mags. So when you selected LEFT, it switched off the RIGHT mag. Confusing, but in the end, it makes sense. ;-) Hoping its a quick and easy fix.
Like your videos Mark. Thanks for doing them.
Sam!! Long time no talk. Hope all is well. Thanks for the comment. I love doing them, but tough to get them done. If people find value in them, I will continue to do them. Blue Skies!!!
wow, im a CFI and I learned way more from this video than i probably should have lol. Great video on an underappreciated aspect of safety.
You aren't the first CFI to tell me that. Glad you found it of value.
Excellent decision. That is a great PIC.
Great learning from this video. Why is EGT rising with only one mag? i answered this question myself when I saw on another video its because with only 1 spark it takes longer to burn all the fuel, therefore more time to heat up the cylinder.
What was fouling the plug? I know of an airplane that had an engine failure after a "plug fouling" incident. The piston was failing from detonation. Once the mag drop was fixed, one more takeoff finished off the engine failure.
The plug was defective (Cracked, not fouled). Needed a replacement.
Did you get a backfire when switching back to both? I wonder what is the right course of action on the ground when one cylinder isn't firing on a mag check and air/fuel is still getting pumped through into the exhaust?
I did not get a backfire and have never gotten a backfire. Maybe because it is not on the one mag very long. Need to think that through. Thanks for a great question.
@@pfflying6275 I only ask because I saw Martin Pauly's video of his N70TB Bonanza for the in flight mag check. And he said that if you get a cold one don't just flip it back to both, go ignition off, mixture idle cutoff, power idle, ignition both and then reintroduce mixture slowly and once then power to get the engine running again, the logic being that if one goes cold on you on one mag, that cylinder is still pumping a mixture in and out the exhaust at cruise RPM which could mean an ignition inside the exhaust once that cylinder is firing again. I thought well that's the scenario you had. So that's why the question. But maybe the exhaust is so hot from the other cylinders running that one going cold and just pumping mixture through into the exhaust only means that the mixture burns immediately in the hot exhaust and doesn't cause a problem short term. No idea. But I wonder... Would love to hear your thoughts.
@@markor2476 Very interesting. I am going to do some research. When you go to both, you obviously will be getting one plug firing, which will burn (inefficiently) the fuel. But what you state is logical. I'll try to get someone at Continental to provide me their thoughts.