Mag Overhaul v/s Inspection

[CharlesHuddleston]

Ok ladies and gentlemen, looking for some more advice. For those that haven’t seen any of my earlier posts, I just moved to the ‘owner’ category. N1157L was purchased after a government seizure, and as of yet I don’t have any old logs or records. Annual is done, squawks are being addressed, compressions were great, and prop is being overhauled. The last inspection item are the mags. Would it be more cost effective to just get them overhauled or simply ask for the 500hr inspection? Trying not to be frugal, just want to be cost-conscientious! Mag failure rates??? I have found some online overhaul estimates, but don’t see any ‘inspection’ estimates. Thanks for the guidance. It has always been so easy to just check out the rental and fly away, but so looking forward to having the freedom, increase in speed, and range!!!

[kortopates]

A 500 hr IRAN should be all you need till you overhaul the entire engine.


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[CharlesHuddleston]

Good idea about the prop inspection. I am not commercial, by thought that prop times had to be tracked, and unlike an engine TBO, were more mandatory. Without logs, would an IRAN inspection work to start a new prop log?? Thanks again!

[Guest]

45 minutes ago, bluehighwayflyer said:

Agreed. Get Aaron Williams at Select Aircraft Services in Texas to IRAN your mag and someone who knows how to follow Lycoming Service Instruction 1508C to install it and you will be good to go. Also, if it isn't too late just have your prop shop IRAN your prop. If you are a U.S. Part 91 operator, prop overhauls are unnecessary and destructive. 

I don’t think that the Lycoming S/L applies to his TCM engine.  None the less correct installation and setting the timing following SB94-8D is just as vital.

Clarence

Edited June 14, 2018 by M20Doc

[dlmorris]

You didn't state which model you own so I looked it up. I've been flying the K Model for 23 years. Just getting my second engine installed (factory). I've flown the plane over 3500 hours. 20% of that time in the flight levels over the Rockies or headed east in the jet stream.  All that to qualify my experience with the TSIO360MB engine. I'm assuming you have an LB engine.

Mags live a hard life tucked back there in the heat. Pressurization just add more heat. I've had three mag failures. I won't bore you with the details but I will share my experience with "overhaul/inspection" matters. Neither is option IMHO, is worth the money. If you need proof, secure a copy of the shop guidelines associated with each process. At best, it's a bench test under circumstances drastically different than the working environment of thin air and high temperatures. I had a "recently overhauled" mag fail at FL220 over the Rockies with the wife on board. Nearest airport-40 miles away. Nearest airport with a maintenance facility - twice that distance. Vacation interrupted/AOG expenses and inexperienced hands diving deep into the bowels of my bird. Take away, never again as that was the third time I had experienced mag failure on so-called "recently overhauled" mags (under 150 hours).

My practice these days....mags come off the plane at 500 hours (period). I bought new mags (yes "new"). I paid the core charge and kept the old mags. I have my mag shop replace everything in the case (yes, even the coil). The backup mags are in the hangar ready for the next swap. No issues since then and believe me I'm saving money and my marriage.