Sender: "Marvin Kaye" <marv@lancaironline.net>
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Date: Fri, 11 Mar 2005 10:15:56 -0500
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Subject: RE: Slick Mag Failures
Thread-Topic: lml Digest #1148
Thread-Index: AcUmKZyReRArHWsGQv2M0HR8Z2rKewAHaHag
From: "Halle, John" <JJHALLE@stoel.com>

Here is another Slick mag horror story.  About three months ago, I =
started getting an occasional miss in my engine (once or twice a =
flight.)  Over time, it got slightly more frequent but it was never more =
than one every few minutes.  With some experimentation, we discovered =
that pulling the LASAR circuit breaker solved the problem.  Also =
discovered that, while pulling the CB during ground run-up made a 300 =
rpm difference, doing so in flight made no difference to any engine =
parameter, regardless of the altitude at which it was done.  Hooking the =
controller box up to a laptop resulted in a perfect test score so the =
box and the mags went back to Unison (where nothing happened to them for =
10 days but that's another story.)  Found out yesterday that the box =
tests perfect but BOTH mags are shot!  I have 320 hrs. tach time on =
them.

I learned the mag mantra early on (probably on my first preflight in =
1967): mags are the world's most inefficient ignition system but we use =
them because they are SIMPLE, RELIABLE and SAFE.  And I believed it as a =
religious doctrine.  When I built my airplane, I selected the LASAR =
system precisely because it had not one but two of these safe, reliable =
things that would work no matter what if the new-fangled electronics =
failed.  Now I discover that for the last God knows how long, I have =
been flying around over mountain ranges and in hard IFR with TWO mags =
that went in the dumpster as soon as the Rockford people saw them.  As a =
final irony, they are pretty close to the only "Certified" parts on my =
engine (IO-540 exp).

I am getting a discount on two replacement mags which I intend to use =
while I figure out what electronic system to go to.  I intend to check =
them frequently, and I don't mean the run-up check that I have done =
before every take-off and that has always been perfect.  Check out =
whatever Deakin article claims that runup checks are a complete waste of =
time, which I now put more stock in than I used to.  I have no idea if =
the controller box is contributing anything but I intend to test that =
too when I get it reinstalled.  And I still don't know why the engine =
missed only with the LASAR system on.  Without it, I would presumably =
still be fat, dumb and happy (instead of being only two of the =
foregoing) flying around with two "shot" mags tbat do just fine on =
runup.