Magnetos
At Valley Aero, we pride ourselves in being known as one of the best magneto troubleshooting, repair and overhaul shops around. The incredible depth of experience our engine shop staff brings to this field gives us an unsurpassed ability to quickly troubleshoot and fix tricky, hard to diagnose magneto problems. Over the years, we’ve seen just about every type of magneto fault possible, and we’ve built up a huge knowledge base on how to fix them.
Generally, aircraft magnetos are well made, reliable devices. Over time there have been a few that were troublesome…the Slick 4001 “throwaway” series comes to mind...but for the most part, if properly cared for, your mags should give years of reliable service.
Magneto Safety
Impulse coupled magnetos are designed to start your engine with very little rotational movement. All it takes is a few degrees rotation of your prop to fire the impulse coupling. If your magneto is not properly grounded, your aircraft is an accident waiting to happen.
Here's how to properly check your mag grounding: TCM Service Bulletin 653
Magneto Maintenance - 500 Hour Inspections Are Critical
Magnetos are the heart and soul of your ignition system and they absolutely must be maintained to avoid serious problems.
Every magneto should be removed from the engine, disassembled and inspected at 500 hour intervals.
Failure to do so can lead to engine failure caused by broken gears, failed points, failed coils, cracked distributor housings or sheared drive shafts.
One of our most common findings on aircraft pre-purchase inspections is failure to do 500 hour magneto inspections. We’ve found mags that had close to engine TBO on them without ever being opened up. When we do open these mags, we often find cracked gears, severely pitted points, cam followers worn well beyond manufacturers specs and a host of other potential engine failure causing defects.
We cannot stress enough, the importance of following a 500 hour inspection schedule on magnetos.
Years in Service
If your mags have been in service for more than 12 years, even if you haven’t flown 500 hours in that time, it is critical that they be inspected.
We’ve seen a number of instances where low hour, but high calendar time, magnetos have failed in flight due to the nylon gears becoming brittle with age. The failure usually happens on cold days, shortly after takeoff because the already brittle plastic is subject to rapid heating and cracking.
It always results in instant magneto failure.
Should I Overhaul My Slick Mags?
During the regular 500 inspection cycle, it's common to replace one or two components on Slick mags, but eventually they reach a point where they need a major overhaul. We've found when Slick mags need more than minor parts, it's cheaper to send them back to Slick for a core credit and purchase new ones.
When you replace your mags, you should always replace the ignition harness at the same time. Slick offers quite reasonable pricing on new magneto/harness kits.
How About Bendix Mags
Bendix mags can often be completely overhauled and re-certified at a very reasonable cost. We always maintain a good inventory of Bendix parts so we can usually overhaul your Bendix magnetos without a lot of down time for your aircraft.
Peace of Mind
If you're unsure of the condition of your magnetos, or if you've already gone beyond the 500 hour inspection limit or 12 year lifespan, give us a call and make an appointment to inspect your mags.
The peace of mind you'll gain in knowing your mags are not going to let you down is well worth the few hundred dollars a typical mag inspection costs.
Each of these mags has been red tagged as unairworthy. Are you absolutely sure your magnetos don't belong with this batch. Give us a call and let's talk about your mags.