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  #1  
Old 08-26-2015, 05:12 AM
pierre smith's Avatar
pierre smith pierre smith is offline
 
Join Date: Jan 2005
Location: Louisville, Ga
Posts: 7,840
Default Dual mag failure SIMULTANEOUSLY!

(Moderator note: because it involves equipment common to RV's, this is RV-related.)

My son has helped build several RV's during his A@P apprenticeship.

Last Tuesday, a Cirrus 22 dead sticked to my airport from 19,000' on a cross country. He tried switching tanks, fuel pump on, to no avail. Fortunately, my stepson is a Cirrus trained A@P. He came home from work and diagnosed it as DUAL mag failure!


The plastic gears had stripped on both mags. The driving gears in the accessory section operated smoothly.

He had two mags overnighted and installed them the next day. The engine fired up on the second blade, ran fine and they test flew it and the gent went home to Tampa.

The airplane has a 4 bladed composite MT prop and the thinking is that there is not much vibration damping and could be a causative factor.

The engine parameters were downloaded to a memory stick and forwarded to Cirrus for examination to try and get to the root of this, since they only had 200 hours on them and the factory rebuilt IO-550.

Amazing,
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Pierre Smith
RV-10, 510 TT
RV6A (Sojourner) 180 HP, Catto 3 Bl (502Hrs), gone...and already missed
Air Tractor AT 502B PT 6-15 Sold
Air Tractor 402 PT-6-20 Sold
EAA Flight Advisor/CFI/Tech Counselor
Louisville, Ga

It's never skill or craftsmanship that completes airplanes, it's the will to do so,
Patrick Kenny, EAA 275132


Dues gladly paid!

Last edited by scrollF4 : 08-26-2015 at 06:15 AM.
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  #2  
Old 08-26-2015, 05:18 AM
David-aviator David-aviator is offline
 
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Location: Chesterfield, Missouri
Posts: 4,514
Default

Amazing indeed with the history of magnetos.
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  #3  
Old 08-26-2015, 06:27 AM
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pierre smith pierre smith is offline
 
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Location: Louisville, Ga
Posts: 7,840
Default Yep

The magneto repair facility definitely wanted to examine the mags.

To me, the likelihood of a dual mag failure would be akin to my chances of winning the lottery.

We don't know whether one failed 30 minutes to an hour before the second failure either. We may find out after Cirrus downloads the memory stick.

Best,
__________________
Pierre Smith
RV-10, 510 TT
RV6A (Sojourner) 180 HP, Catto 3 Bl (502Hrs), gone...and already missed
Air Tractor AT 502B PT 6-15 Sold
Air Tractor 402 PT-6-20 Sold
EAA Flight Advisor/CFI/Tech Counselor
Louisville, Ga

It's never skill or craftsmanship that completes airplanes, it's the will to do so,
Patrick Kenny, EAA 275132


Dues gladly paid!
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  #4  
Old 08-26-2015, 06:54 AM
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DanH DanH is offline
 
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Slicks or Continental/Bendix?
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  #5  
Old 08-26-2015, 07:37 AM
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sbalmos sbalmos is offline
 
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Location: Liberty Twp, OH
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Default

Oh this should be interesting to hear updates on. The school I rent from has a similar SR22 with the 4-blade MT prop. Keep me updated Pierre, if not in this thread.
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  #6  
Old 08-26-2015, 08:01 AM
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pierre smith pierre smith is offline
 
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Location: Louisville, Ga
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Continental/Bendix, Dan. My stepson also told me that there's a service letter out to NOT use the gear aligning tool on those mags because it could damage the tooth and then the trouble begins.

Best,
__________________
Pierre Smith
RV-10, 510 TT
RV6A (Sojourner) 180 HP, Catto 3 Bl (502Hrs), gone...and already missed
Air Tractor AT 502B PT 6-15 Sold
Air Tractor 402 PT-6-20 Sold
EAA Flight Advisor/CFI/Tech Counselor
Louisville, Ga

It's never skill or craftsmanship that completes airplanes, it's the will to do so,
Patrick Kenny, EAA 275132


Dues gladly paid!
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  #7  
Old 08-26-2015, 08:34 AM
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Beer30? Beer30? is offline
 
Join Date: Jul 2006
Location: Longmont, CO
Posts: 215
Default What are the chances of that happening?

Pierre,

The obvious take away is that you should buy a lottery ticket, right now!

David
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  #8  
Old 08-26-2015, 08:56 AM
F1R F1R is offline
 
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Location: ____
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Default

Like Dan asked are they Slicks or Bendix Mags?

I would like to think there was a single event like the mother of all backfires that nearly KO'd the gears or an install procedure that did the same.

I once witnessed an R22(Helicopter) with freshly rebuilt bendix mags that settled back on the pad as the internal plastic gears failed right after the first run up. There have been SB's over the years for bad lots of gears that should get thrown out. The mag shop had installed brand new bad gears.

If your ticket wins Pierre, you will need to share with David.

Last edited by F1R : 08-26-2015 at 09:08 AM.
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  #9  
Old 08-26-2015, 09:31 AM
pierre smith's Avatar
pierre smith pierre smith is offline
 
Join Date: Jan 2005
Location: Louisville, Ga
Posts: 7,840
Default Will do

Cirrus is examining the data downloads and the mag rebuilder is inspecting the failed ones as well.

I'll keep you all updated as my stepson gets the information.

BTW, does anyone on here know if the Lightspeed ignition systems ha a Continental STC?

Best,
__________________
Pierre Smith
RV-10, 510 TT
RV6A (Sojourner) 180 HP, Catto 3 Bl (502Hrs), gone...and already missed
Air Tractor AT 502B PT 6-15 Sold
Air Tractor 402 PT-6-20 Sold
EAA Flight Advisor/CFI/Tech Counselor
Louisville, Ga

It's never skill or craftsmanship that completes airplanes, it's the will to do so,
Patrick Kenny, EAA 275132


Dues gladly paid!
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  #10  
Old 08-26-2015, 11:44 AM
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N941WR N941WR is offline
 
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Location: SC
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Default

Quote:
Originally Posted by pierre smith View Post
...
The airplane has a 4 bladed composite MT prop and the thinking is that there is not much vibration damping and could be a causative factor.

....

Amazing,
My neighbor has had three mage failures in less than 150 hours. They have been attributed to the Sensenich ground adjustable prop. He now spins a Catto and the problems have gone away.
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Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html
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