Dual mag single mag failure

[Tim Jodice]

This past week I was flying home I noticed that all of my EGTs went up. No change in CHT, oil temp or pressure.

The only thing I could think of what would caused all EGTs to rise without anything else changing quickly was a mag not working. It was running fine and I was about 10-15 minutes away from the airport I didn't see any reason to try to figure it out in the air.

Once on the ground I did a usual mag check and one was completely inoperative, no rough running it simply stopped working completely. 

I found out that the coil had failed. 

Would you have tried to figure out the cause in the air? 

[N201MKTurbo]

Probably.

[carusoam]

Tim,

I had your answer after the first paragraph...

EGTs rise Just like the run-up...

For the same reason...

+1 for inflight mag check...

Because the more you know while flying, the better off you are...

Leaving the switch on both may not be the best option with a dead mag...
 

Got data?

Compare run-up data to your dead mag data... see how similar they are...

Great Pirep!

Best regards,

-a-

[takair]

13 hours ago, Tim Jodice said:

This past week I was flying home I noticed that all of my EGTs went up. No change in CHT, oil temp or pressure.

The only thing I could think of what would caused all EGTs to rise without anything else changing quickly was a mag not working. It was running fine and I was about 10-15 minutes away from the airport I didn't see any reason to try to figure it out in the air.

Once on the ground I did a usual mag check and one was completely inoperative, no rough running it simply stopped working completely. 

I found out that the coil had failed. 

Would you have tried to figure out the cause in the air? 

Not sure. If it is running smooth and temps are manageable with power and mixture  and airport is in range it might be best not to touch anything. If it was misfiring it might be another story. There is that possibility that touching things could make things worse. In this case you would have realized that switching to the bad mag shut off the engine. Now, you should reduce power before bringing the good mag back so that you don’t ignite all the raw fuel in the muffler. I would probably forget that part due to me fear of silence in the air, so I might be buying a muffler too. Anyway, you made it with no drama and are safe, so I would call it successful. 

[Tim Jodice]

Just now, takair said:

If it is running smooth and temps are manageable with power and mixture  and airport is in range it might be best not to touch anything. If it was misfiring it might be another story. There is that possibility that touching things could make things worse.

This is what was going through my mind. 

[DXB]

43 minutes ago, takair said:

Not sure. If it is running smooth and temps are manageable with power and mixture  and airport is in range it might be best not to touch anything. If it was misfiring it might be another story. There is that possibility that touching things could make things worse. In this case you would have realized that switching to the bad mag shut off the engine. Now, you should reduce power before bringing the good mag back so that you don’t ignite all the raw fuel in the muffler. I would probably forget that part due to me fear of silence in the air, so I might be buying a muffler too. Anyway, you made it with no drama and are safe, so I would call it successful. 

Couldn't agree more. If it's running smooth and making good power, simply landing and troubleshooting on the ground is the best course action.  If you had switched to the dead side and gotten an uncomfortable silence, it would be ideal to pull the mixture out before switching back the good mag to prevent a big backfire.  I had a mag almost completely die in flight but not entirely, leading to oscillating EGTs and RPMs and some vibration.  It happened at full power during climbout at 3000ft and was very anxiety inducing, but it was still making good power. I had a large runway behind me, and I wasn't 100% certain it was a mag. So I was very hesitant to touch anything under those conditions. Luckily the misfiring mag cut out completely as I reduced power to descend and the landing was uneventful.   

[Andy95W]

I agree with Dev and Rob.  10-15 minutes from destination- I'd wait and get it on the ground, while monitoring it closely.  More than 30 minutes? Probably try and troubleshoot.

Like Dev said, high power mag check with a dead magneto could lead to a muffler-blowing backfire.

[Dustin Kurath]

Cetainly good to get it on the ground. I am experiencing this right now with my Ovation. On the last leg of my trip to seattle this weekend, I had a mag start running rough and eventually quit over the mountains east of Seattle. I diverted to Moses Lake, had the faulty mag changed out (right mag), and took off this morning with a good working engine. An hour into the flight, the left mag started going bad on me, but did not completely fail, so I diverted to Bozeman, and am awaiting a call from the shop tomorrow. Likely I will be here for a couple of days while they install another new mag, this time on the left.

[carusoam]

Long time no see, Dustin!

Any idea how many hours you have on your IO550, and mags?

Typically, MSers have a tendency to OH mags on a 500hr cycle...

Best regards,

-a-

[kmyfm20s]

2 minutes ago, Dustin Kurath said:

Cetainly good to get it on the ground. I am experiencing this right now with my Ovation. On the last leg of my trip to seattle this weekend, I had a mag start running rough and eventually quit over the mountains east of Seattle. I diverted to Moses Lake, had the faulty mag changed out (right mag), and took off this morning with a good working engine. An hour into the flight, the left mag started going bad on me, but did not completely fail, so I diverted to Bozeman, and am awaiting a call from the shop tomorrow. Likely I will be here for a couple of days while they install another new mag, this time on the left.

I flew that exact route a week ago and was thinking to myself about how I hope I don’t have a mag failure or worse. That is some beautiful rugged terrain. I have had 3 Mag failures and each time I failed to isolate and fly on the good mag. Now it will be the first thing I do on a rough running engine. EGT’s and CHT go crazy and can potentially cause a cylinder to go. Needless to say my plane ran perfectly on that flight but the thought of potential mag failure Occurred to me so I ordered a Surefly electronic ignition when I got to Jackson, when.

[GeeBee]

On 9/6/2020 at 6:43 PM, Tim Jodice said:

This past week I was flying home I noticed that all of my EGTs went up. No change in CHT, oil temp or pressure.

The only thing I could think of what would caused all EGTs to rise without anything else changing quickly was a mag not working. It was running fine and I was about 10-15 minutes away from the airport I didn't see any reason to try to figure it out in the air.

Once on the ground I did a usual mag check and one was completely inoperative, no rough running it simply stopped working completely. 

I found out that the coil had failed. 

Would you have tried to figure out the cause in the air? 

A greater emergency did not exist, there was no reason to switch mags. If the engine had quit or was developing insufficient power, yes but since that was not the case you did the. right thing.

 

[bmcconnaha]

5 hours ago, GeeBee said:

A greater emergency did not exist, there was no reason to switch mags. If the engine had quit or was developing insufficient power, yes but since that was not the case you did the. right thing.

 

Agreed.  running smooth, id land and diag.  i lost mag on my sr22TN one time (turbo normalized, cruise is always done lean of peak) and it was change your underwear rough.  i was over mountains, 15mins from my destination.  I did diag in air.  single mag ops, rich of peak smoothed it out.  Let tower know i had an ignition system issue and they got me on the ground quickly,    

[WaynePierce]

On 9/7/2020 at 7:28 AM, takair said:

Not sure. If it is running smooth and temps are manageable with power and mixture  and airport is in range it might be best not to touch anything. If it was misfiring it might be another story. There is that possibility that touching things could make things worse. In this case you would have realized that switching to the bad mag shut off the engine. Now, you should reduce power before bringing the good mag back so that you don’t ignite all the raw fuel in the muffler. I would probably forget that part due to me fear of silence in the air, so I might be buying a muffler too. Anyway, you made it with no drama and are safe, so I would call it successful. 

I've had this issue before, but luckily I  was on the ground. But, if flying and I lose a mag (I have the -D engine) I would do the mag check, just like on the ground but while flying? If I find I have a dead mag, before I turn back to both, or the good mag, I should pull the power to idle before I turn the key back? This whole scenario, while flying is frightening. I've never run a tank completely dry, either. I like the sound in the cabin rather than the silence.

[takair]

1 hour ago, WaynePierce said:

I've had this issue before, but luckily I  was on the ground. But, if flying and I lose a mag (I have the -D engine) I would do the mag check, just like on the ground but while flying? If I find I have a dead mag, before I turn back to both, or the good mag, I should pull the power to idle before I turn the key back? This whole scenario, while flying is frightening. I've never run a tank completely dry, either. I like the sound in the cabin rather than the silence.

That is the question...to do the mag check or not.  I think the answer is...it depends.  If running rough, it may be best to determine which mag is smooth and leave it there.  If you switch to the quiet one, fuel continues to pump and switching to the good mag may cause a loud explosion as the fuel in the muffler ignites.....thus the idea of low power and mixture lean.  If I had to do this, it would be preferable to be over an airport.  If things are smooth and landing assured, I would lean towards avoiding the drama and just figure it out on the ground.  On one mag, usually richer mixture and lower power will keep temps in check.  Switching the mags likely won’t help if it is already failed.  I recall one unusual case many years ago where a guy had intermittent rough running.  The mechanic told him to try in flight mag check.  The next time it happened was shortly after takeoff.  Turned out the ignition switch was coming apart.  He somehow ended up in OFF, but the key no longer turned back on.  Executed a safe landing in a field.  Rare event, but it happened and remains in my brain.  Can’t find the NTSB report.  Sometime in the early 90s around Rochester Nh.  

[carusoam]

Fear is a great motivator to learn more...

By the time you learn enough to not be fearful.... you may be an engineer, medical doctor, and CFII when you are at ease...

PP thoughts only...

Best regards,

-a-

[takair]

6 hours ago, carusoam said:

Fear is a great motivator to learn more...

By the time you learn enough to not be fearful.... you may be an engineer, medical doctor, and CFII when you are at ease...

PP thoughts only...

Best regards,

-a-

I think I was least fearful when I didn’t know about all these ways to get hurt...and the list keeps growing....23 was a great age.....