By Harry Fenton, Director of Business Development and Product Support, Kelly Aero
Routine maintenance requirements and all special service actions required by Service Bulletins and
Airworthiness Directives typically require that the magneto serial number or part number be referenced
to verify compliance. The OEM data found on the magneto data plates is always the baseline to establish
the applicability of the compliance of a required maintenance or safety action.
However, what is required when an OEM data plate has been replaced by a company that is not the OEM
for the magneto? What if a serial number is added to the data plate that is different than the OEM serial
number? Do OEM requirements still apply? The bigger question: Is the magneto considered an FAA
legal part if the OEM data plate has been removed and replaced by a non-OEM data plate?
Replacement Data Plates- Is This Legal?
The simple answer is “yes”, Kelly Aero replaces worn and damaged OEM magneto data plates with new
Kelly Aero data plates. But, the “yes” answer is not as simple as it sounds. The FAA considers the
management and disposition of OEM data plates attached to FAA-PMA articles as serious business. The
real world for Kelly Aero is that there is no option: worn data plates must be replaced when magnetos
are inspected or overhauled. In most cases, magnetos returned to Kelly as cores for overhaul, or for the
500-hour inspection, may be legible, but not in a useable condition to continue on in service.
The continued use of the OEM data plate for ongoing service and compliance becomes a safety issue if
the information on the data plate becomes illegible. The only practical and safe solution is to make a
new data plate stamped with the information from the old, worn data plate.
The FAA has strict regulations against the removal and replacement of airframe, engine, propeller, and
life-limited parts, though. They spell out what can, and cannot be done in the Federal Code of
Regulations, Part 45. The FAA states, specifically, that data plates of Type Certificated or Life Limited
items may be removed in the course of maintenance and must be reattached to the item from which
they were removed. Replacement data plates for these items can only be provided by the OEM, but the
FAA must approve and accept that process. This concept has been drilled into mechanics thinking by
the FAA and industry guidance. The general understanding is that all data plates are forbidden to be
The data plates of component articles that are FAA-PMA approved, such as magnetos, are not as strictly
controlled and the FAA can approve a repair process that does not require OEM approval for data plate
replacement. Kelly Aero’s process to replace the worn OEM data plate with a new Kelly Aero data plate
is part of our FAA-approved Repair Station Quality Manual. This manual details the process to replace
data plates, but also documents the strict record-keeping and traceability procedure required to
preserve the OEM data plate and magneto model information.
Bendix and Slick magnetos worked on by Kelly Aero for overhaul or 500-hour inspection are completely
disassembled and all parts are cleaned and inspected to make the magneto look and work like new.
During the teardown and inspection process, the OEM data plate is removed from the magneto frame in
order to strip the paint from the magneto and repaint it to a new condition. The OEM serial number and
magneto part number are permanently coded onto the magneto frame to preserve the record of that
part. All of the information on the data plate becomes part of the extensive overhaul record of the
magneto as it progresses through the Kelly Quality system.
When the inspection and re-work steps are completed, a list of parts to overhaul or to complete the 500
hour inspection of the magneto is generated and added to the magneto record. At every step in the
process, from disassembly to completion of the overhaul, the OEM data is part of the documentation
After the magneto assembly is completed, a new Kelly Aero data plate is made for the magneto. The
data plate will show the OEM serial number, the Kelly Aero Overhaul serial number, and the part
number of the magneto. The new Kelly Aero data plate is attached and the inspected magneto looks as good
as new. An FAA Form 8130-3 Authorized Release Certificate is generated to document and release the
500-hour inspection magneto to service.
If the magneto is overhauled, the data plate marking will be slightly different as compared to the 500
hour inspection. Kelly Aero Overhauled magnetos are treated more like new production magnetos and
a unique Kelly Aero serial number is assigned to the magneto. The OEM serial number is also retained
and both the Kelly Aero and OEM serial numbers are engraved on the new magneto data plate.
The Dual Identity of a magneto overhauled by Kelly Aero
After overhaul, an FAA Form 8130-3 Authorized Release Certificate is generated to document
completion of the overhaul process and to authorize the release to service of this part by Kelly Aero. It is
at this point that the magneto develops a dual identity based on the specific requirements that apply to
the OEM serial number or the Kelly assigned a serial number. Both serial numbers become equally
important in terms of ongoing maintenance compliance.
The most common misconception is that the Kelly Aero data plate changes the requirements to comply
with OEM maintenance guidance. This perception is 100% wrong. All OEM Service Bulletins and
Airworthiness Directives continue to apply to the magneto based on the underlying OEM magneto data,
regardless if it was overhauled by Kelly Aero or by any other company.
However, the Kelly Aero overhaul uses Kelly manufactured FAA-PMA parts and additional processes of
inspection and workmanship which are not part of the basic OEM minimum requirements. These
additional features make the Kelly Aero overhaul unique. These unique features may be affected by
inspections or service needs different than, or in addition to, than OEM requirements. To track service
requirements of the content added by Kelly to an overhauled magneto, a unique Kelly Aero assigned
serial number is added to the data plate and is listed on the FAA Form 8130-3 Authorized Release
Certificate supplied with the magneto.
Given the “dual Identity” of the magnetos serviced by Kelly Aero, the replacement Kelly Aero data plate
is clearly more than just a simple cosmetic replacement. The Kelly Aero data plate ensures legibility for
the service cycle of the magneto, which is required for ongoing compliance and safety requirements.
The Kelly Aero data plate also adds the extra layer of traceability of the Kelly added components and
workmanship. Ultimately, ALL applicable OEM and Kelly Aero service requirements must be complied
with after the magneto is released to service, and the new Kelly Aero data plate assures that action can
Do you have a question about Kelly Aero products or piston engine ignition systems? Contact us at