Had my first inflight magneto failure yesterday

Mopauly

Mopauly

Pre-takeoff checklist
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Paul Steklenski
It wasn't fun. Luckily it happened after I had already dropped off my 15 rescue dogs. Initially tshoot of this failure was quite confusing as the engine continually sounded as if it wanted to shut down. Fortunately I was just two miles south of a class Delta when it occurred and they cleared the decks for me to land. Did not declare but they did everything in their power to help.

Not something I hope to experience again, however I'll be much better prepared for this scenario again if it does. I'm not sure what a normal mag failure is like, but this one made it seem like the engine wanted to quit about every 30 seconds.
 
Did you continue to fly on "both" or did you shut it down to the one that was working?

-Skip
 
I had a bad mag once and it definitely made it better to turn off the bad one. A guy in our EAA chapter had one failing and it was misfiring so bad it was causing the engine to shake and stumble he thought it was going to die. Wouldnt run much above idle. Turning off the bad mag made it run fine.

Glad you got down OK.
 
I've had about half a dozen mag failures in my flying career (mostly with dogs on board). What airplane were you flying? Lycomings and Continentals handle magneto failures differently in my experience.
 
If you do a magneto check at full power and turn to the bad magneto, the engine will quit and when you turn it back on it will backfire BIGTIME!
 
coloradobluesky said:
If you do a magneto check at full power and turn to the bad magneto, the engine will quit and when you turn it back on it will backfire BIGTIME!
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This sounds as if it comes from experience....:lol::lol::lol:

That was my first thought, was the bad magneto turned off in flight after it failed?
 
The symptoms appeared more fuel related to me at first - I did end up checking the mags but probably didn't stay on them long enough to rule it out. The behaviour of the engine was troubling to the point where I no longer cared about troubleshooting, and just wanted to get on the ground.

The aircraft was a Piper Warrior 160; I normally use an Arrow for these flights however it was already booked for the day. At the time it failed I already had just over 4 hours on the airplane for the day; the runup I had done just 5 minutes before showed no indication of the mag failing.
 
Generally I've found that Lycomings handle mag failures very well, so your experience is surprising. I've literally run Lycomings on one mag for hours at a time (in the lab, on purpose) and never had so much as a hiccup. My in-flight mag failures on Lycomings have also been non-events. That makes me think the other side probably had a weak ignition system.

On Continentals, I've tended to have one or more cylinders spike CHTs and show indications of detonation after a mag failure (rapidly rising CHTs requiring a significant increase in fuel to control), followed by the sort of "engine sounding like it wanted to die" you were talking about after an hour or more. However, my experiences on Continentals were with higher time engines with higher time ignition systems.
 
Good job putting her down safely.
 
Just leave the mixture knob where it was for both mags for mixture running on one mag.

And another thing, you are legal to finish the flight on one mag. Once you land, you wont be legal to take off on one mag. So plan that for where you land. (somewhere with a mechanic)
 
It's possible had I stayed on one mag and ruled it out it would have been fine, but at that point I had a 2 beautiful wonderful runways right in front of me over a river and I wasn't going to take any chances.

I'm not sure on the manufacturer of the mags - these are rental aircraft, and my post inspection of the engine was just to look for anything visual I could relay to my FBO before I called them. I didn't learn it was a mag failure until this morning when the FBO had a chance to get to the aircraft and check - up until then I kept running the entire scenario through my head wondering what I missed or what I had done wrong.

Had I been at 5500' it may have been different - but I was at '2500 to stay under the Bravo and was just transitioning the Delta when it occurred - all I kept thinking about was how lucky I was to have this airport right in front of me.
 
Ive had it happen in a 1970's Lycoming 172 and in an Lycoming 0-360. The 172 was at runup, so it wasnt full power but it still backfired. What happens is the fuel air mixture continues to circulate through the engine and gets to the exhaust and when you turn it back on the fuel air mixture gets ignited in the exhaust. Can also backfire without being turned back on. It sort of happens abruptly. At least thats what happened with those. More likely to be severe with full throttle.
 
coloradobluesky said:
Ive had it happen in a 1970's Lycoming 172 and in an Lycoming 0-360. The 172 was at runup, so it wasnt full power but it still backfired. What happens is the fuel air mixture continues to circulate through the engine and gets to the exhaust and when you turn it back on the fuel air mixture gets ignited in the exhaust. Can also backfire without being turned back on. All sort of happens abruptly. At least thats what happened with those. More likely to be severe with full throttle.
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May be a difference in manufacturer. My mag failures have been in Continentals.
 
It was the most bizarre thing - as if the ignition was being turned off and on; after the 4th or 5th time I was done and just wanted down.
 
Fearless Tower said:
May be a difference in manufacturer. My mag failures have been in Continentals.
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I have had to deal with cracked exhaust components due to those big bangs. Usually, it's a problem when the pilot, during runup, accidentally turns the mag switch to OFF and back on again; the accumulated raw air/fuel mix in the muffler explodes and the concussion can break stuff. I have even found intake flange gaskets broken by it; the slight bit of valve overlap at the top of the exhaust stroke lets the blast pass right through the cylinder and set off the mix in the intake.

The pilot needs to hold that mag key by its flats, not by its edges. Pinching the edges is asking for it to slip and snap to off.

The explosion won't happen at idle, when one might check for mag grounding.
 
The mags can fail in several different ways. If the coil or capacitor fails, it just quits firing, and RPM drops a bit. If the distributor gears are worn enough and slip, or if crossfiring starts happening due to moisture or carbon contamination, the sparkplugs connected to that mag can fire at the wrong times, seriously reducing power and maybe even stop the engine. That's when some fooling with the mag switch is in order.
 
May be a stupid question but I may as well ask - since 'Off' and 'Both' are on the ends, and mag 1/mag 2 in the middle positions - what's the proper procedure to go down to the 'good' magneto in this scenario? If you encounter what the OP did while running on 'Both', do you go to the mag in the first position and if it runs great, just leave it alone there? What if that happens to be the 'bad' magneto? Will the engine come alive if you then go past that position and onto the next mag?
 
I believe the intention is to isolate the failing magneto - in my case the engine wasn't running rough, but rather every 30 or 60 seconds it acted like it wanted to shut off completely, so I didn't spend much time focused on the mags. But yes, to your point, you want to isolate the failing mag and get on the good one to get the airplane where you need to go without further incident.
 
It depends on how the mag fails. This is the scenario for when one mag simply quits putting out spark, like the wire comes off the post. There are other scenarios.

If mag L completely fails, then the engine will run rough and have less power and the CHTs and EGTs will be unfamiliar. If you turn from Both to mag R, it will continue to run. If it runs the same on R as it did on Both, you may want to stop troubleshooting and leave it on R. If you turn it to mag L the engine will quit. If you turn it back to mag R, then engine will restart (and might backfire).

If you are holding altitude, don't do anything in a hurry. You will probably have to adjust the trim because of reduced power. Airspeed will drop. You may want to do a mag check just to find out what is wrong, maybe not. If the engine quits during the mag check, be QUICK to turn it back to the running position. Ive never seen a mag fail procedure spelled out in a POH. If it were me, I'd get flight following if I werent on it already. Whether to finish the flight on the remaining mag or land somewhere else is going to be your decision.
 
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How much time on the mags.???
 
Good decision to land. If engine does not work properly in 10 seconds and there is a runway in front of you , this should be no brainer
 
Had a mag failure in a helicopter while giving tours at Mt Rushmore max load min fuel about 8000 DA... that was kind of scary. It would not maintain altitude.

I've played around with my instructor and other friends. The helicopters I tried it in wouldn't even maintain a in ground effect hover on one mag.
 
Mopauly said:
It was the most bizarre thing - as if the ignition was being turned off and on; after the 4th or 5th time I was done and just wanted down.
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I had something similar this summer.

The engine, TSIO-520 by Continental in a C-207, just quit while over Funter Bay in south east Alaska. Because of clouds, I was at 1300 agl and was heading towards Juneau when the engine acted as if the mag switch was shut off. I did the flow, switched tanks, mixture rich, prop forward, throttle full, electric fuel pump on and switch the mags between left and right. Nothing changed. As I was looking for a suitable piece of beach, (the tide was in and not much beach to land on) I checked the mags again. This time I found that if I held the key in a certain way the engine would come back to life. I found the sweet spot and held the key and continued on to Juneau and landed without anymore problem.

The one incompetent mechanic that is also the DOM, with a lot of help from a real mechanic found that the key switch had failed shorting out the mags.

Good job getting it down without injury to the airplane, yourself or others.

 
blueskyMD said:
Good decision to land. If engine does not work properly in 10 seconds and there is a runway in front of you , this should be no brainer
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Depends on altitude. At 1000 AGL, maybe test the mags while maneuvering to land, but there really isn't time. At 5000 AGL or more with an airport right below, you have some time.
 
Zeldman said:
I had something similar this summer.

The engine, TSIO-520 by Continental in a C-207, just quit while over Funter Bay in south east Alaska. Because of clouds, I was at 1300 agl and was heading towards Juneau when the engine acted as if the mag switch was shut off. I did the flow, switched tanks, mixture rich, prop forward, throttle full, electric fuel pump on and switch the mags between left and right. Nothing changed. As I was looking for a suitable piece of beach, (the tide was in and not much beach to land on) I checked the mags again. This time I found that if I held the key in a certain way the engine would come back to life. I found the sweet spot and held the key and continued on to Juneau and landed without anymore problem.

The one incompetent mechanic that is also the DOM, with a lot of help from a real mechanic found that the key switch had failed shorting out the mags.

Good job getting it down without injury to the airplane, yourself or others.
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I also suspected this possibility, so far the jury is out as the plane is still awaiting full repair.

MAKG1 said:
Depends on altitude. At 1000 AGL, maybe test the mags while maneuvering to land, but there really isn't time. At 5000 AGL or more with an airport right below, you have some time.
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Agreed - had I been at my 5500' cruise with the pups on board, I would have given it more time - but at 2500' over the city of Philadelphia, I wasn't going to mess around.
 
Mags aside, I want to know how you got 15 dogs in a Piper Warrior!?
 
Here's the ATC audio; I pulled it from LiveATC and edited out the other traffic. Conversation starts right after they asked if I was declaring.

 
JCranford said:
Mags aside, I want to know how you got 15 dogs in a Piper Warrior!?
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This is the only reason I fly - I've had up to 23 in a Piper Archer. I'm hoping with a 205 or 206 I can get up to 50. I'm highly focused on efficiency, I pack as many crates in as space and weight and balance will allow.
 
Wow, good on you for the mag difficulties and the doggie runs!

Yeah, you too Ted!
 
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JCranford said:
Wow, good on you for the mag difficulties and the doggie runs!

Yeah, you too Ted!
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Thanks! :)

To elaborate, like he said, it comes down to efficiency and crates. It also comes down to dog size. The most I ever had in the 310 was over 40, but they were almost all puppies. When I started doing trips in the Aztec (upgrade from the Mooney), it was pretty normal to have in the range of 15-20 dogs, but they were typically bigger dogs. My average dog weight was probably about 50 lbs in those days, and always a 75-80 lb dog on board. The groups I work with now mostly send small to medium size dogs, average size is probably 25 lbs. If we did a real "puppy run" with all litters of puppies, it would be easy to do 75, probably more. It just depends on the sending and receiving groups, since they're the ones who make the decisions on which dogs to send, mostly based off of what's available and what's most adoptable. Having worked with groups all around the continent, it's always interesting to see how different groups decide to send different dogs. It's a huge variety

While the number of dogs is always impressive, I've tried to avoid focusing on the number, and rather just focused on keeping the plane at maximum capacity for all flights. After all, big dogs deserve to be rescued just as much as small ones, even though you can sometimes fit 5-10 puppies in the same space as 1 big dog. That said, I've never flown a Great Dane, and it's been a while since I've flown a dog greater than 45 lbs. Again, that's more function of the groups than anything.

Aside from being extremely rewarding, flying dogs is also very interesting and a lot of fun. You meet a lot of great people. Flying and animal rescue are where I've met most of my favorite people.
 
Good thread for those of us who haven't experienced mag failure....yet. Glad you got 'er down safe.
 
The one time I had a 140lb Great Dane in the Arrow - this dog was so big he could barely sit down, and had to ride behind the seats to fit.

IMG_7227.jpg
 
Mopauly said:
The one time I had a 140lb Great Dane in the Arrow - this dog was so big he could barely sit down, and had to ride behind the seats to fit.

View attachment 49485
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Very cool photo! One tip - I used to let one or two dogs be "co-pilot" (uncrated) but I added a practice of not allowing any transport dogs to be transported without a crate unless there was someone else to attend to them. I had a few times where dogs that seemed fine behavior wise then started trying to get up and move about the cabin. One managed to get himself wrapped up in my headset and pulled hard enough to break the wires. Fortunately I had a spare. I also had a few that ended up underneath the rudder pedals. Reality was I had some pretty bad scares where I realized that the dog could've brought us all down. While these dogs are vetted for personality traits, some will still just not behave well in a plane and need the crate to keep everyone safe.

As you know, 99% of the time, the dogs just go to sleep and are great passengers. That 1% can be challenging and you won't necessarily know who they are until you get going. Just sharing a few war stories since I want to make sure that you're around to keep saving dogs, too. :)
 
I always have a pup ride shotgun, but have never had a real problem - as you mentioned I pay very close attention to personality traits before loading the one that will be copilot. This past flight puts us at 483 animals since May of 2015, hoping to hit 500 by end of year. I only ever had one sit on the floor and stick his head under the dashboard, from where I promptly pulled him back out, but like you said, the concern is always there.
 
If ATC helped you out, write them a thank you letter. You'll have some friends for life.
 
coloradobluesky said:
If ATC helped you out, write them a thank you letter. You'll have some friends for life.
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I was thinking about that - sending them something as a thank you for their help.
 
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