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Magneto failure in general, Was: P Mags

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dave(at)abrahamson.net
Guest

Posted: Fri Feb 23, 2007 4:27 am Post subject: Magneto failure in general, Was: P Mags

I am running a Slick mag (4371) and a Lightspeed Plasma II+ 

electronic ignition on my TMXO-360.  Haven't started the engine yet, 

so I don't know what a Lightspeed failure and good mag, or mag 

failure and good Lightspeed, would sound like/do to the RPM, CHT, and 

EGT.  Nevertheless, here's my thinking.  I am pretty sure that the 

second case (mag failure) would be undetectable in flight, or hard to 

detect since the Lightspeed does most of the ignition work.  Should I 

get a MP drop, EGT rise, and roughness in flight, however, I'd 

probably be justified in first suspecting a Lightspeed 

failure.  Emergency action would be to turn the Lightspeed switch to 

OFF to see if there was any change in the fault conditions.  If not, 

assume I'm on my one mag and divert to an airport with 

services.  However, if the engine ran rougher, turn the Lightspeed 

switch back on, enrich, carb heat on, see what happens, 

divert.  Lastly, if engine quits, implying mag failure, pull mixture 

to idle cut-off, wait 10 seconds, turn Lightspeed back on, slowly 

move mixture to full rich (maintain glide slope, declare emergency, 

locate rabbit's foot), and hope for the engine to come back on.

Does that sound right?  Thanks.  David

mprather(at)spro.net
Guest

Posted: Fri Feb 23, 2007 5:18 am Post subject: Magneto failure in general, Was: P Mags

It's possible that a mag can fail in such a way that it's timing is

dramatically off.  In such a case, it would make sense to turn off the

magneto and fly just on your LSE.  I don't see that in your procedure.

Regards,



Matt-



 	  Quote: 	
		   

 <dave(at)abrahamson.net>



 I am running a Slick mag (4371) and a Lightspeed Plasma II+

 electronic ignition on my TMXO-360.  Haven't started the engine yet,

 so I don't know what a Lightspeed failure and good mag, or mag

 failure and good Lightspeed, would sound like/do to the RPM, CHT, and

 EGT.  Nevertheless, here's my thinking.  I am pretty sure that the

 second case (mag failure) would be undetectable in flight, or hard to

 detect since the Lightspeed does most of the ignition work.  Should I

 get a MP drop, EGT rise, and roughness in flight, however, I'd

 probably be justified in first suspecting a Lightspeed

 failure.  Emergency action would be to turn the Lightspeed switch to

 OFF to see if there was any change in the fault conditions.  If not,

 assume I'm on my one mag and divert to an airport with

 services.  However, if the engine ran rougher, turn the Lightspeed

 switch back on, enrich, carb heat on, see what happens,

 divert.  Lastly, if engine quits, implying mag failure, pull mixture

 to idle cut-off, wait 10 seconds, turn Lightspeed back on, slowly

 move mixture to full rich (maintain glide slope, declare emergency,

 locate rabbit's foot), and hope for the engine to come back on.

 Does that sound right?  Thanks.  David

BobsV35B(at)aol.com
Guest

Posted: Fri Feb 23, 2007 6:02 am Post subject: Magneto failure in general, Was: P Mags

Good Morning David,

  

 Sounds Good To Me!

  

 However, I am not familiar as to what Lightspeed uses to adjust it's timing  so it is difficult for me to evaluate your scenario.

  

  Does the Lightspeed unit adjust it's timing based on reading some parameter  of the actual combustion event or does it adjust based on mapped  parameters?



  

 I am sure you are aware that if you have fixed timing for both ignition  systems and one fails, there will be a substantial increase in  EGT.  

  

 Given the existence of a good all cylinder EGT system, it is easy to find a  faulty spark plug or bad harness lead by observing the action of the EGTs. If  all is well, the EGTs on each cylinder will rise about the same amount when one  ignition system is not firing..

  

 If one plug or harness lead is bad, the EGT will stay nice and steady when  the good one is lighting the fire and drop precipitously when the bad plug  should be firing the cylinder.

  

 If you could educate me on the operation of the Lightspeed, I would  certainly appreciate the education!

  

 Happy  Skies,



Old Bob

AKA

Bob Siegfried

Ancient Aviator

Stearman  N3977A

Brookeridge Air Park LL22

Downers Grove, IL 60516

630  985-8503



  

 In a message dated 2/23/2007 6:31:25 A.M. Central Standard Time,  dave(at)abrahamson.net writes:

  	  Quote: 	
		  I am    running a Slick mag (4371) and a Lightspeed Plasma II+ 

electronic ignition    on my TMXO-360.  Haven't started the engine yet, 

so I don't know what    a Lightspeed failure and good mag, or mag 

failure and good Lightspeed,    would sound like/do to the RPM, CHT, and 

EGT.  Nevertheless, here's    my thinking.  I am pretty sure that the 

second case (mag failure)    would be undetectable in flight, or hard to 

detect since the Lightspeed    does most of the ignition work.  Should I 

get a MP drop, EGT rise,    and roughness in flight, however, I'd 

probably be justified in first    suspecting a Lightspeed 

failure.  Emergency action would be to turn    the Lightspeed switch to 

OFF to see if there was any change in the fault    conditions.  If not, 

assume I'm on my one mag and divert to an    airport with 

services.  However, if the engine ran rougher, turn the    Lightspeed 

switch back on, enrich, carb heat on, see what happens,    

divert.  Lastly, if engine quits, implying mag failure, pull mixture    

to idle cut-off, wait 10 seconds, turn Lightspeed back on, slowly 

move    mixture to full rich (maintain glide slope, declare emergency, 

locate    rabbit's foot), and hope for the engine to come back on.

Does that sound    right?  Thanks.  David

	


 



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n744bh(at)bellsouth.net
Guest

Posted: Fri Feb 23, 2007 8:39 am Post subject: Magneto failure in general, Was: P Mags

David, 

  

 I'm using one mag and one Lightspeed Plasma II+ also on an IO-360.  I  can almost guarantee that if the Lightspeed unit fails you will know it  immediately by the sound of the engine.  I've tried turning off one or the  other in cruise and the difference between a mag being off and the Lightspeed  being off is very audible.  And when switching from mag only to mag and  Lightspeed together you can feel the difference in the seat of your pants.   Your only issue here is, as you have said, telling if there has been a mag  failure.

  

 Bill

 Glasair Super IIS

 [quote]   ---

mlas(at)cox.net
Guest

Posted: Fri Feb 23, 2007 9:22 am Post subject: Magneto failure in general, Was: P Mags

The LSE ignition system uses manifold pressure for detection for the timing advance.  Their is an option for  electrically advancing the system as well. But I haven’t used that function.  

   

Mike  

   

--

BobsV35B(at)aol.com
Guest

Posted: Fri Feb 23, 2007 11:54 am Post subject: Magneto failure in general, Was: P Mags

Good Afternoon Mike,   

 Very interesting! I guess I will have to check their website and see if I  can figure out what they are doing. 

  

 Do you run one LSE and a magneto or two LSEs?

  

 If you do run one of each, have you noticed what the EGTs do during a pre  takeoff run up/ignition check and how that changes if a high cruise power  ignition system check is performed in flight?

  

 I would assume that the pre takeoff check would have all EGTs rise when  either ignition system is off and fall when they are both operating. Does it do  that?

  

 For the high power check, I would assume the change night be variable based  on any number of factors including the altitude.

  

 If the engine uses LSEs only, I would imagine the EGTs would react the  same as with dual magnetos.

  

 Any thought?

  

 Happy  Skies,



Old Bob

AKA

Bob Siegfried

Ancient Aviator

Stearman  N3977A

Brookeridge Air Park LL22

Downers Grove, IL 60516

630  985-8503



  

 In a message dated 2/23/2007 11:34:59 A.M. Central Standard Time,  mlas(at)cox.net writes:

  	  Quote: 	
		     

The LSE ignition    system uses manifold pressure for detection for the timing advance.  Their is an option for  electrically advancing the    system as well. But I haven't used that function.   

    

Mike   

 	


 





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dave(at)abrahamson.net
Guest

Posted: Sat Feb 24, 2007 5:08 am Post subject: Magneto failure in general, Was: P Mags

Thanks.  Very glad that someone out there has the same setup as 

me.  When you turned off the mag in flight, what effect did you 

see?  If it's slight/minimal, perhaps this means that mag failure in 

flight won't be noticed until you get on the ground.  One other 

question is, what is your shutdown procedure or pre-shutdown 

procedure?  Do you pull to idle cutoff and then switch both the mag 

and LSE off, or do you shut one or the other off and then pull to 

idle cutoff?  I'm implying that shutting the LSE off prior to 

shutdown would test the mag, and then you could pull to idle cutoff, 

still burning up the fuel left in the system.  Lastly, if you would 

show me your emergency procedure checklist relating to the engine, 

I'd be very interested.  Thanks.

David

dave(at)abrahamson.net
Guest

Posted: Sat Feb 24, 2007 5:36 am Post subject: Magneto failure in general, Was: P Mags

I do cover that eventuality in "Lastly, if the engine quits...", but 

running a diagnosis that stops a rough-running -- but otherwise 

healthy engine, obviously needs to be refined.  The core issue, I 

think, is how you figure out the mag has failed/malfunctioned in 

flight if the symptoms are very subtle, as I suspect they are if the 

LSE is firing away lustily.  I've asked Bill Hibbing what his 

experience is with shutting off the mag in flight, and I plan to test 

that myself when I take flight in a couple of months.  It may be that 

your only safe alternative is to shut off the mag to see if that 

makes any difference, enrich and add carb heat, and if the roughness 

persists, land and test the mag on the ground.

David

BobsV35B(at)aol.com
Guest

Posted: Sat Feb 24, 2007 6:56 am Post subject: Magneto failure in general, Was: P Mags

Good Morning David,   

 Considering the vast array of engine monitoring equipment that is available  today, don't you think that we should be able to get a lot of information from  those systems that most of us use?

  

 I find that most of my impending spark plug, harness and magneto problems  give good early warnings on the engine monitoring equipment during a high power  inflight ignition system check. 

  

 With a bit of monitoring, many mechanical aberrations can also be detected  way before the engine gets rough.

  

 Happy  Skies,



Old Bob

AKA

Bob Siegfried

Ancient Aviator

Stearman  N3977A

Brookeridge Air Park LL22

Downers Grove, IL 60516

630  985-8503



  

 In a message dated 2/24/2007 7:43:36 A.M. Central Standard Time,  dave(at)abrahamson.net writes:

  	  Quote: 	
		  -->    AeroElectric-List message posted by: David Abrahamson    <dave(at)abrahamson.net>



I do cover that eventuality in "Lastly, if    the engine quits...", but 

running a diagnosis that stops a rough-running    -- but otherwise 

healthy engine, obviously needs to be refined.  The    core issue, I 

think, is how you figure out the mag has    failed/malfunctioned in 

flight if the symptoms are very subtle, as I    suspect they are if the 

LSE is firing away lustily.  I've asked Bill    Hibbing what his 

experience is with shutting off the mag in flight, and I    plan to test 

that myself when I take flight in a couple of months.     It may be that 

your only safe alternative is to shut off the mag to see if    that 

makes any difference, enrich and add carb heat, and if the roughness    

persists, land and test the mag on the  ground.

David

	


 



  



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n744bh(at)bellsouth.net
Guest

Posted: Sat Feb 24, 2007 5:35 pm Post subject: Magneto failure in general, Was: P Mags

David,



With the Lightspeed operating I doubt if you'd notice anything if the mag 

failed.  When I shutdown on the ground I just pull the mixture although 

shutting down with just the mag operating sounds like something I may have 

to try.  As far as an engine emergency I have just 3 steps.  1.  FLY THE 

AIRPLANE.  2. Take up a  nearest toward the nearest suitable airport.  3. 

Turn off the fuel and declare an emergency in case of a destructive failure. 

Otherwise, troubleshoot if time permits.



We did have an interesting case withaCirrus powered by Continental.  It 

seems that the gear on one of the mags stripped and it was firing all over 

the place.  Unfortunately the person that was flying it at the time didn't 

bother to check the mags and flew for 200 miles in this condition.  It 

destroyed the engine and it could have been prevented if he had simply 

switched them off one at a time.  I don't really know why he didn't land 

when it happened and he's very lucky that the Feds didn't get wind of it as 

it was a sure violation.



Bill

---

dave(at)abrahamson.net
Guest

Posted: Sun Feb 25, 2007 5:44 am Post subject: Magneto failure in general, Was: P Mags

You're right, I'm sure.  The last airplane I owned was an Archer III 

in which I had an Insight GEM installed.  My RV7 has a GRT dual efis 

with EIS and I have not had a chance to devote time to learning about 

all the information I will be presented with, or how I am going to 

interpret all that data.  There is much to learn, but I figure that I 

need to develop emergency procedures based on my current experience 

set (feel, sound, EGT, CHT), knowing that I will/will need to refine 

these procedures as I learn to best interpret a full screen of 

graphical engine information.

David

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