Kelly Aero receives calls daily from customers in need of product support to select a Kelly product or
technical assistance after the product has been installed. Due to our long industry experience at Kelly
Aero, the vast majority of calls are routine, and we can quickly provide an answer to any question asked
to us. However, calls get a bit complicated when the first several minutes are spent trying to determine
what the topic is when a customer calls.
All too often, customers start their phone call with a vague request of “I have a Lycoming engine and I
need a harness” or “…the magneto on my engine isn’t working…” While all conversations have to start
somewhere, the reality is that some conversations stop as quickly as they start. The information
provided by the customer is missing too many important details or the customer simply does not know
the details. It can be frustrating to a customer who is in a rush or in the middle of working to solve a
problem when the conversation with Kelly becomes a game of 20 Questions. Unfortunately, this game
of 20 Question is particularly frustrating for both sides on a busy Friday afternoon when an airplane
needs to fly on Saturday morning.
Just like how a pilot completes a checklist before the airplane is ready to fly, customers and mechanics
can complete a simple checklist of items prior to calling that will the customer to ask the right questions
quickly, and the Kelly Aero representative to provide an accurate answer.
What is the engine make and model you are working on?
Invariably, the Kelly Aero Product Support person will need the following specific information:
- Which company manufactured the engine? Is it Continental, Lycoming, Superior, Franklin,
As a note to this comment: The name of company who overhauled the engine is not useless,
but also not particularly useful. Starting the conversation with “I have an engine overhauled by
Empire Engines” is good to know, but does not really provide any magneto information. What is
useful is the specific original manufacturer of the engine, such as Continental or Lycoming.
- What is the complete engine designation?
Ok, you know that you have a “four cylinder Lycoming” or a “550 Continental” but specific
details are critical. For example, the magnetos used on a TSIO-550-K are much different in
configuration and troubleshooting than the magnetos installed on an IO-550-A. Provide as
much exact information as possible including the prefix, engine number and suffix, such as O-
320-D2J, O-470-R, TSIO-550-C.
Additionally, some of the Kelly Aero Technical reps are experienced A&P mechanics with deep
knowledge of specific engine and airframe applications. If a customer calls in with what seems
to be a magneto operation issue, a bit of discussion may lead to other known areas of concern
unique to specific engine models.
What is make and model of magneto?
Simply referring to a magneto “a Kelly mag” or maybe as a “Bendix” or “Slick” usually is too broad of a
description. No surprise, but Kelly will need the exact magneto part number details to put the known
service history or troubleshooting techniques into perspective.
- Is the OEM manufacturer of the magneto Bendix or Slick?
While Kelly takes it as a compliment when a customer says, “it’s a Kelly Aero mag”. While Kelly is
an OEM for replacement parts, we are also a service provider to overhaul OEM magnetos. The
magneto data plate may be labeled with Kelly Aero, but the magneto it is attached to is Bendix
or Slick magneto, but overhauled by Kelly Aero.
- What it is the magneto model series? Bendix makes the 20 series, 1200 series, and Dual D2000
and D3000 series magneto. Slick mags will be either a 4300 or a 6300 series. Drilling deeper,
the part number of the magneto is critical as this identifies the configuration of the magneto. As
an example, the Bendix 20 Series 10-51360-37 and the 10-500514-1 are approved for the same
engine applications, but very different in the details of how the magnetos are mounted to the
engine and how the ignition switch p-lead attaches. But, these seemingly small details can add a
lot of time and expense to an otherwise simple installation if a mechanic has to alter a P-lead or
order different mounting clamps and gaskets.
What is the magneto serial number?
The new data plate that Kelly Aero affixes to all Bendix and Slick overhauled magnetos has lots of
information that the Kelly Aero product support representative will need to know. Most important will
be the serial numbers stamped on the data plate.
The Kelly Aero data plate will display both the OEM issued serial number and the Kelly Aero issued serial
number. The OEM serial number is important to track any OEM specific service issues or compliance to
OEM Service Bulletins. The Kelly Aero assigned serial number links the overhaul of the magneto to
records maintained by the Kelly Aero Repair Station quality management records. The Kelly Aero serial
number is required to confirm compliance to Airworthiness Directives, certain manufacturer Service
Bulletins and the general timeframe when the magneto was serviced.
When was the magneto installed? Calendar date and hours, please…
Hours of operation and calendar time are two different ways to measure time in service for magnetos,
and each tells a story independently, and together to put the magneto service history into perspective.
For example, calendar time frames the reference for the type of parts or service issues known to be in
effect during a particular year or month. Hours in service provides a view of how quickly, or slowly,
hours were accrued on the magneto.
The relationship of calendar time and hours is very important for the Kelly Aero product support
specialist to assist with customer questions. For example, a customer may comment that they have a
question regarding a magneto with 100 hours. However, was that 100 hours accrued over two months
or ten years? Low magneto time is one story, but low magneto time over many years tells a different
Harness Nuts and Spark Plug Type. Let’s have this discussion again…and again…and again…
Search through Kelly Aero ignition system articles and ignition harness selection has been a topic more
than once. Ignition harnesses have a few options and do required the buyer to do some homework as
part of the selection process. Virtually all customers are able to determine which custom fit harness is
required for their engine using Kelly’s Ignition Harness Application Data by clicking on this link:
But, there are also many, many times that customers, typically private owners who are learning the
process to buy their own parts, who need a bit of guidance on selecting between ignition harnesses that
fit Bendix or Slick magnetos. As always, the most confusing part is the difference between 5/8-24 or
3/4-20 spark plug nut connections.
Sorting out the difference between spark plug nut sizes is usually the substance of most phone calls.
The 5/8” and 3/4” refers to the diameter and thread pitch of the spark plug barrel, not the wrench used
to remove the nuts. The easy way to determine nut size follows:
- A 3/4” wrench is used to remove 5/8”-24 spark plug nuts used on REM style spark plugs
- A 7/8” wrench is used to remove 3/4”-20 spark plug nuts used on RHM style spark plugs
Who is asking the question: an A&P mechanic….or an Owner?
Let’s be realistic: Aircraft owners are more deeply involved in the maintenance process of their
airplanes than ever before. Owners provide important operational information used by mechanics and
product support representatives. Owners research and purchase parts used on their airplanes,
consulting their mechanic, parts supplier, and manufacturer sales and support teams. Internet owners
groups can be useful, but very often lead to some good answers. The same groups also generate
answers that may not be completely accurate or even completely incorrect. Ultimately, owners are
going to have to spend their hard earned money and the educated owner is motivated to do research on
the products that they own or want to buy.
By no means does this imply that Kelly Aero does not want to talk to aircraft owners. In fact, we
encourage and support aircraft owners to contact us to work through product selection or product
operation questions. But, calls can become frustrating when the owner is speaking in terms which are
not aligned with standard industry terminology used by trained mechanics. Additionally, Kelly Aero
product support answers may overwhelm an untrained caller with all sorts of terms and references that
will make no sense. It usually require a lot of repetitive discussion to explain terms and concepts that
are easily understood, with no further explanation, by an A&P mechanic.
From the technical support perspective, Kelly Aero can be less technical, use or explain more of the
specific terms that an owner may not understand. In effect, Kelly Aero can tailor our conversation with
the customer to speak with terminology useful to the caller. The end result is a much better experience
for both the customer and the Kelly Product Support representative.
Kelly Product Support does not replace required reading material!
When working on a critical process, such as ordering internal components to the magneto, completing
magneto assembly, or performing magneto to engine timing, the Kelly Product Support Representative
will ask, “Do you have a manual?”
To be blunt, working on a magneto is not the same set of skills as required to change the light bulb
inside your refrigerator. The magneto and ignition harness are components critical to the safe operation
of the engine. It only makes sense that anyone who plans to or is working on an item critical to safe
operation would have a set of instructions in their hands. It is reasonable and obvious that a properly
rated individual should have access to and use the service manual. Nevertheless, it is also a good idea
for an educated owner to read the service manual to have an idea of the work required for a particular
While Kelly Aero is eager to assist our customers, discussions with a Kelly Product Support
Representatives do not replace the need- or FAA requirement- to have a service manual for the
component that will be serviced. Copyright laws restrict Kelly Aero from sending copies of OEM service
manuals to customers, but Kelly can distribute our own documents freely.
A brief note regarding Kelly Aero manuals: Keep checking the Kelly Aero web page during 2021! We are
working on new product application manuals, product service manuals, and supplementary Service
Letters to make it easy for users of Kelly Aero products to service all of the parts and assemblies that we
Are you ready to make the call?
Get your notes ready and give Kelly Aero a call at 334-286-8551!