500 Hour Slick Mag Inspection

[flickroll]

My Slicks are approaching 500 hours so they're getting close to the recommended inspection time. I read through the Unison overhaul manual for the Slicks, and it doesn't seem to be an overly difficult task, but thought I'd solicit feedback from those who've been there, done that.

How difficult is it?

Any tips/traps to watch for?

What parts are typically replaced at this time interval? Thanks

[twsurveyor]

Originally Posted by flickroll

My Slicks are approaching 500 hours so they're getting close to the recommended inspection time.How difficult is it?

Any tips/traps to watch for?

What parts are typically replaced at this time interval? Thanks

I asked this question a month or two ago and got answers and advise from one end of the spectrum to the other. So.............. I asked our resident AI and he basically said (on an experimental aircraft) "If it ain't broke then don't fix it"!

He did say, however, to watch the mag timing and if it starts to "creep" and/or you have problamatic symptoms (hard to start engine, excessive mag drop etc., etc.) then do the inspection as advertised.

Hope this helps,

[Ironflight]

Jim,

I found that at my first 500 hour inspection (OK, ok, I forgot it until 600....), I didn't have to replace a thing - just checked the E-gap and internal timing, buttoned them up, and re-installed. It's almost time to do them again - I'm expecting that, based on current performance, they'll be fine again.

Paul

[flickroll]

Thanks Paul...sounds likes relatively easy chore so I'll give it a try. I did notice some of the Slick parts are pretty expensive, such as the coil and a few others. If you need to replace some of those components you're probably better off buying a new mag.

[Ironflight]

Originally Posted by flickroll

If you need to replace some of those components you're probably better off buying a new mag.

My general conclusion exactly! So it doesn't hurt to open them up and see how they look.

[Walt]

Originally Posted by twsurveyor

I asked this question a month or two ago and got answers and advise from one end of the spectrum to the other. So.............. I asked our resident AI and he basically said (on an experimental aircraft) "If it ain't broke then don't fix it"!

He did say, however, to watch the mag timing and if it starts to "creep" and/or you have problamatic symptoms (hard to start engine, excessive mag drop etc., etc.) then do the inspection as advertised.

Hope this helps,

I understand the philosophy here but don't agree.... good maintenance is more than just waiting for something to fail before fixing it, but fixing it BEFORE failure occurs.

If you never look for the signs of impending failure by doing timely inspections and prefer to just wait for things to fail, then your machine may let you down at a very inopportune time

[Bill Wightman]

My Slicks had only 330 hours since new on them, but since they were included with the engine I bought, I thought I'd open them up.

Glad I did. Timing was OK, but points, rotor, brushes and cap contacts all showed wear. And lots of carbon dust in there. I think they'd have been airworthy, but now I KNOW.

Its easy work. Go do it.

[nomocom]

Originally Posted by flickroll

My Slicks are approaching 500 hours so they're getting close to the recommended inspection time.
Any tips/traps to watch for?

It is not difficult if you have the appropriate literature and aren't in a time crunch. Once you get one open and inspected, you can choose the parts you want to replace, get them ordered, and get it back together. Allow yourself at a minimum a week, more like two weeks. If you can borrow a mag, that's even better for minimizing downtime.

Risk management tip.

IIRC, Mike Busch has some interesting write ups on equipment failures in certified aircraft- highest right after repairs, then very low for a long time, then finally as tach time and calendar time increase, the probability steadily increases, though slowly.

So, if you do one mag at a time, you can minimize the risks to flight caused by infant mortality. Offset the repairs by a year or 50 hours, so if you get a bad batch of parts, or misunderstand the repair, you still have a mag you haven't futzed with.