-----= Original Message-----
From: John Barrett
Sent: Oct 22, 2013 11:17 AM
To: lml@lancaironline.net
Subject: [LML] Re: Hot TITs on X country leg. LIVP

=
Thanks Colyn for in dept= h reply.

Now I have a plan. I hope others pick up on this too. <= o:p>

H= ow often do you do this?

John

From: Lancair Mailing = List [mailto:lml@lancaironline.net] On Behalf Of Colyn Case
Se= nt: Tuesday, October 22, 2013 6:05 AM
To: Lancair Mailing Lis= t
Subject: [LML] Re: Hot TITs on X country leg. LIVP

go to 15,000. Get well lean of peak in cruise setting= . shut down one mag (er...one ignition system). If you get a m= inor rpm change, you are good. If you get major roughness, your igni= tion needs attention.
Magneto ign= itions are subject to:
- ch= ampion spark plug has gotten out of spec for resistance
- spark plug gap too high
=
- air in mag is not pressurized or is wet. &nbs= p;(check the filter)
- any = defects in the harness

On Oct 22, 2013, at 7:55 = AM, John Barrett wrote:

=
Thanks to Gary an= d Colyn and everyone else who have schooled me on this event. I think= I understand what was happening better.

Someone sugge= sted testing ignition during flight to get a true picture of what is going = on. I would like to know more about that. I assume you would no= t want to do this at high power settings with a TSIO 550? Can anyone = explain parameters of safety and what exactly one should do to test this?

Most assuredly if I had done an ignition check after la= nding but prior to shut down the cause of the event would have been v= ery clear and saved much time, effort and grief. It will be inc= luded in my checklist for the future.

Regards,
John= Barrett

From: Lancair Mailing List [mailto:lml@lancaironline.net]= On Behalf Of Colyn Case
Sent: Monday, October 21, 2013 4:= 55 PM
To: Lanca= ir Mailing List
Subject:&nb= sp;[LML] Re: Hot TITs on X country leg. LIVP

So to get to GA accident rates we as a fleet have f= ree of failures that could contribute to a fatality (on all systems includi= ng the pilot) 99.999% of the hours flown.
A system that fails 1% of the hours flown is about 1000= times more dangerous than that.
Something to think about when selecting components.

<= /div>
On Oct 21, 2013, at 3:15 PM, Gar= y Casey wrote:
=
I was going to guess that. Honest, I was :-= ). But just one correction: The high exhaust temperature with o= ne ignition off isn't due to "incomplete fuel burn." The burn is virt= ually complete whether running on one spark plug or two. But the burn= RATE is much different. With two plugs there are two flame fronts an= d the burn completes sooner. The slower burn rate on one plug means t= hat a significant portion of the burn happens during the expansion stroke a= nd less heat is converted to power. Hence the exhaust temperature is = higher. Further, when the mixture is leaned past the best power (or m= aybe peak EGT) the flame travel is even slower and consequently the exhaust= temperature will likely just continue to go up when leaning, not peak and = go down.

Most people have had great luc= k with the Lightspeed system, but I am on my fourth in just 400 hours with = none of the failures were due to installation errors and all were different= problems. The last one has been running perfectly for over 100 hours= , so I guess I'm past the near side of the bathtub curve :-). Klaus w= as never very forthcoming about the failures, but here is what happened:
1= . With about 10 hours on the plane the inverter power device for one = channel (two spark plugs) quit and then after about 10 minutes it completel= y shorted and blew the fuse.
2. One of the channels started to inter= mittently trigger off the previous channel, putting the spark at about 140 = BTC. Now, THAT gets your attention. Fortunately, it happened on= the ground at the beginning of the takeoff roll. No real explanation= , but "later model" components were installed.
<= /div>
3. One of the channel= s would quit after 10 or 20 minutes of flight. Again, no real explana= tion was given. The ignition coils were also replaced at that time as= the "new" coils were supposedly "better."
4. Still going strong at = 400 hours. I will say it starts and run faultlessly, and I REALLY lik= e the improved performance above 10,000 feet produced by the extra timing a= dvance.
<= span style=3D"font-family:"Helvetica","sans-serif";colo= r:black">Gary Casey

Time to fess up. The failure mode turned out to be a f= ailed electronic igni=3D
tion sy= stem. I run one Plasma III lightspeed and one mag. The lightspe= ed q=3D
uit and I didn't recogni= ze it. It had to have happened during climb out or a=3D
t level off. The run up prior to take o= ff was entirely normal. =3D20

The hot TIT's and EGT's were the result of incomplete fuel burn by the ma= g t=3D
hat was the only ignition= still running. Fuel in the exhaust stacks burns i=3D
n the turbines and heats everything up real fas= t. I don't understand why le=3D
aning made it worse though. Can anyone explain that?
=
Lest anyone jump on Klaus, let me be q= uick to admit it was not a failure of h=3D
is system but rather an installation defect. As a ma= tter of fact he got o=3D
n= the phone with me on a weekend day and helped trouble shoot it. He o= verni=3D
ghted a loaner to me wh= en I didn't have enough tools or access to do adequat=3D
e system checks and did not laugh at me too badly = when the loaner did not fi=3D
x = the problem. A check of the ground for the power circuit showed about= 2 K=3D
ohms resistance. T= he fix was to wire in another ground.

Best regards,
John Bar= rett