So your prized aircraft is down for an annual and your A&P says it’s time for your 500hr inspection.
Some pilots choose to overlook the importance of the inspection.
However, the 500-hour inspection is the single most important magneto service event.

Whether you are an owner, flight school, commercial operator, or engine overhaul shop, you can ensure continuing trouble-free and safe service of an aircraft magneto.

The 500-hour magneto inspection is critical to the safe operation of magnetos. While not a required service action as an airworthiness directive, it is considered critical and
mandatory by magneto OEM’s and is considered a good, common-sense maintenance practice by aircraft mechanics.

The 500 hour is scheduled preventative maintenance and to avoid expensive unscheduled maintenance. If a magneto is not inspected every 500 hours, then the risk of an unplanned component failure that can cause inconvenient and unplanned maintenance at a location far from an aircraft owner’s home airport is certain to occur.
The cost of one or more nights of hotel, car rental, meals, missed work, lost flight revenue will easily be offset by the relatively small cost of a 500-hour inspection.
The inspection is not limited to magnetos which have accumulated 500 hours in service. A 500
hour inspection can be accomplished at any hours of magneto total time in service. In some cases, some magneto and engine combinations may result in the need to perform magneto maintenance more frequently than 500 hours. Pressurized magnetos used on Continental and Lycoming engines operate in demanding, high altitude environments and require more maintenance than other types of magnetos.
Dual contact, or retard breaker magnetos that use the Shower of Sparks starting system typically require more frequent maintenance. Magnetos used in Shower of Spark applications require frequent
inspections to ensure that fuel-injected Lycoming and Continental engines do not experience hard
starting problems.


To begin the 500-hour inspection process, an inspection return form is downloaded from the Kelly Aerospace website. Complete one form for each magneto that is returned. Before boxing the magneto, remove the drive gears attached to the magneto. Return the complete magneto, with the drive gears removed, and do not forget to include the completed 500-hour inspection form. The magneto is returned directly to Kelly Aerospace, 1400 East South Blvd, Montgomery, AL 36116 with Attn
500-hour inspection marked on the box.
When the magneto is received, work starts within 24 hours of receipt. Plan for four working days to complete the inspection, plus shipping time to return to the customer. Kelly Aerospace ships via UPS or
FedEx and can ship worldwide. Check your shipper delivery zone time chart to determine the duration of shipping time to and from Montgomery AL.
The magneto is disassembled by a magneto technician so that the parts can be inspected and cleaned.
The magneto parts are cleaned and polished as needed. Magneto frames and housings are not repainted but can be repainted if the magneto is upgraded to an overhaul. The magneto parts are
inspected by visual and non-destructive testing, and must meet the criteria established in the Bendix
and Slick Maintenance and Overhaul manuals.
The 500-hour inspection for Bendix magnetos includes new replacement hardware, new contact points,
oil slinger, oil seal, (2) ball bearings, carbon brush, o-ring, felt strip, felt washer, and impulse coupling spring. The 500-hour inspection for the Slick magnetos includes new replacement hardware, new
contact points, and cam, oil seal, (2) ball bearings, carbon brush, distributor gear to comply with

Champion Slick Service Bulletin SB1-15A and impulse coupling spring. An FAA Form 8130 will be provided to document the 500-hour inspection.
Depending upon the condition and service history of the magneto, extra work or parts may be required.
Some of the extra parts would include worn distributor gear, worn distributor block, faulty coil, faulty
capacitor, worn impulse coupling, worn rotor shaft, or parts affected by airworthiness directives.
If any other parts are required, the customer will be contacted for additional charge approval prior to work
being completed.