Building your own panel is completely doable.
We offer some tips on how to get it right the first time.
By Stein Bruch
Given what I do for a living, I get to
see a lot of variety in instrument panels, both professional and homebuilt.
My shop produces finished panels for
builders to install in their projects, but
people may not realize that many of
our customers build their own panels.
While it may appear to be a daunting task, it is entirely possible for a
person of average skill to accomplish.
We’ll take a look at some of the tasks
and tricks that will help you to build
at least some, if not all, of your own
instrument panel.
The Layout
First, we start with the blank panel. In
many kits this is a bare piece of aluminum that may or may not be cut to shape
or have mounting holes. Even in planes
that are built with composite, wood or
other materials, the core instrument
panel is usually constructed of aluminum sheet, though carbon-fiber sheet,
fiberglass or wood may also be used.
Before you start cutting, prepare a
layout of your panel. The easiest way
to start this task is the “paper doll”
method. Gather your choice of avionics
Photos: Stein Bruch, Richard VanderMeulen, Marc Cook, Rick Lindstrom
photos, cut them out, and then tape
them to the blank panel until you have
something that resembles a basic layout.
Don’t worry about your cutouts being
100% to scale; just get them as close as
you can. If possible, arrange the cutout
photos while you’re sitting in the cockpit, pretending you’re flying the plane,
to get a better feel for their position.
For those less tactile individuals
who are more attracted to technology, you can do this same exercise on a
computer with a low-cost CAD (computer-aided design) program, a simple
KITPLANES June 2012
37
All About Avionics continued
paint program, or with pencils, graph
paper and a scanner.
As you build your layout, there are
some things to remember.
1. Resist the urge to create a “nonstandard” layout when it comes to
primary flight instruments and the
arrangement of switches. Many flight
hours by intelligent people have proven
that the standard layout works best, so
it’s wise to follow their lead. Deviation
will leave your plane both less functional and less attractive.
2. Try to keep things lined up as best
you can across the panel, both horizontally and vertically. Symmetry not only
looks good, it greatly reduces strain in
the air and increases the usability of
the entire instrument panel. A willynilly arrangement creates chaos in the
panel and in the wiring behind it.
3. Do not place switches all over the
panel; try to keep them in a centralized location. Resist the urge to locate
a particular switch next to each specific
device. Not only does this require more
movement in the cockpit to perform
various functions, but it also greatly
complicates the wiring behind the panel,
reducing reliability. Plus, it’s just a disorganized way to operate the aircraft.
Place switches in one area, grouped
by logical function such as main power/
alternator/ignition, lighting, avionics and
When cutting out complex shapes, use a pattern or have it cut out for you with a CNC
machine. In the above example, the builder did almost all of the cutouts himself, but had
the Garmin 796 cutout done on a CNC to ensure accuracy of that odd-shape hole.
other similar devices. Also, place them in
order of importance. For example, you
will use the master switch on every flight,
but likely only once. The flap switch
will probably be used more often, and
it’s handy to have it close to the throttle
where it can easily be accessed without
removing your hands from the flight
controls. Also note that circuit breakers
or fuses should be located where they are
both visible and operable.
4. In both side-by-side and tandemseat aircraft, place the main avionics
radio stack so that it can be operated
by the “non-flying” hand. Many tandem drivers claim they can’t turn a
knob with their left hand, but it’s easy
to do and is much safer than switching
Though the camera angle doesn’t show it, the stack of trim
switches/indicators are aligned vertically with the key-switch
hole. Note how the holes for the switches are all aligned and
spaced equidistant.
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KITPLANES June 2012
hands on the stick or reaching across
the panel.
5. The area directly in front of the
pilot should be treated as sacred and
used only for vital elements such as
flight instruments, autopilots, switches
and other items that are important for
regular flight. Don’t waste that space
with items such as ELT remote indicator heads, dimmer knobs, USB ports or
other devices that are not critical.
Cut and Run
Now that you’ve finished the layout of
your panel, it’s time to start cutting,
which you can either do yourself or have
someone do for you. The first option is
not necessarily difficult, but it can be
It’s worth your time to draw all of the cutout details with pencil or
marker before cutting to keep all of your lines straight and even.
Remember to cut holes slightly undersize so you can “file to fit”
the final openings.
www.kitplanes.com
time-consuming. Most pilots are now
using EFISes and other digital boxes,
so cutting the larger square holes is the
easy part; it’s locating and placing various screw holes, switch holes and other
smaller items that can be a hassle. That’s
where the second option comes in. There
are many machine shops and avionics
shops around the country with CNC
machines dedicated to cutting sheet
metal. If you provide them with a good
drawing or computer file, most will cut
your panel for $90 to $250. Taking into
account that you’ll likely spend at least
16 to 20 hours cutting your own panel,
it may be more cost-effective to have one
cut for you, freeing up your time for
other aspects of the build.
Time for Tailoring
After the panel is cut, the next step is to
“dry fit” all of the components, starting
with the radio stack. There are many
ways to do this, but the easiest is to start
with the empty avionics trays, which
can be purchased at a reasonable price
in advance of the main avionics units.
Align them so that the front faces are
close to being flush with each other,
using strong tape to secure the entire
stack. The stack can now be located
in the panel where you will be able to
mount the angles used to secure it.
Your cutout for the radios will be 6¼
inches wide with slight modifications
for various protrusions on some pieces
EFIS
Engine Monitor
AOA
Moving Map
Autopilot
Approach Plates
When mounting rails from adjoining
devices that are very close together, you
can “stair step cut” the rails to keep them
strong within a tight space.
www.Advanced-Flight-Systems.com
Phone:(503) 263-0037
Patents 6,271,769 B1 & 6,940,425
KITPLANES June 2012
39
All About Avionics continued
of equipment. With the panel secured,
you can position the stack in between
the two rails to which the radios will
be attached. To locate things correctly,
the tray fronts should be flush with the
face of the instrument panel (taking into
account any overlays or other things that
may increase the thickness of the panel).
Once everything is held in place, you can
simply drill from the mounting holes in
the panel and into or through the rails,
and then use a Cleco or bolt to hold the
trays in place. Some builders like to use
nut plates to secure the trays, but this is
not mandatory.
Continue mounting other trays for
EFISes, GPSes or instruments before
moving on to switches and circuit
breakers. This allows you to create any
initial bus bars that will gang various
switches and breakers together along
with headset jacks and other miscellaneous items.
As an intermediate step, put all of
the items back into the panel semipermanently; this is where the wiring
process begins. Don’t start painting
yet, because the panel will get dinged
up and scratched before you’re finished
wiring. Place the panel with all of the
components either upside down on a
bench or secured on top, allowing you
Important consideration to bus bar and
breaker layout should be given when
large numbers of breakers are used. This
allows for simplified and organized wiring,
while still allowing multiple busses to be
controlled (three in this photo).
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KITPLANES June 2012
Radio racks are taped together in a mock layout on the bench.
to access the backside. Start the wiring
process with the circuit breakers, fuses,
vertical power and switches. Run the
wires between these items first. If you
run one wire at a time and use either zip
ties or clamps to group them, the harness will turn out well. This is the time
to fabricate any bus bars for attachment
to rows of circuit breakers or switches.
Wiring It
Next, focus on any airframe grounds
that need to be attached to your central
grounding point, and run those wires.
Once most of the switches and circuit
breakers are connected, you can move
on to the avionics. I strongly encourage
people to use colored wires to identify
various components. I use red wires for
power, black for ground, blue for GPS
signals, yellow for lights, green for shield
grounds, and white for standard avionics wiring. Shielded wiring is preferred
for almost all audio connections.
I’m biased, but I’d recommend that
you have the core avionics stack wired
Zip ties are used as disposable holding devices while the circuit breakers and bus bars are
being fabricated. At a cost of around two cents each, they make great temporary fixtures
while you are wiring.
www.kitplanes.com
All About Avionics continued
by a professional. It’s not that expensive
in the overall scheme of things ($500 to
$2500), and it’s cheap insurance when
we’re talking about $10,000 to $20,000
worth of avionics, or more. It’ll also
save you countless hours. Avionics
wiring is not magic, but it is tedious
and takes careful concentration to get
things right. If you do your own harnesses, at least start with a good drawing of all interconnects, and then take
it one wire at a time. When you are
stringing wires, make sure you leave
a bit extra on removable items such as
EFISes or GPSes. I leave anywhere from
6 to 12 inches of extra wire, called a service loop, to easily remove those devices
from the panel and then disconnect the
wires rather than trying to disconnect
them first.
Initial Testing
Once you’re finished with all of the avionics wiring (remember, the switch/
fuse/circuit breaker wiring is already
done), you can proceed with testing
your panel. Before you power anything up, there are a number of things
to consider:
1. Find a device to power the
panel. A 14 VDC power supply is preferred, but a good battery and charger
will also work.
A typical radio stack mounted in an instrument panel with its associated wiring and
antennas attached. Note how the bundles are nicely secured and regularly tied.
2. Check, double-check and triplecheck that you have the + hooked to
power and the – hooked to ground.
More than one customer has called with
a sad story of the power and ground being
reversed; this typically lets smoke out of
the wires and blows up costly items.
3. Have every switch in the OFF
position, and have all circuit breakers
pulled to OFF (or fuses removed from
fuse blocks).
4 . Have a coa x cable with an
antenna hooked into both the transponder and radios. Do not test your
Extra slack (service loop) left in wires attached to screens allows you to remove
components from the panel without having to disconnect them first.
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KITPLANES June 2012
radio transmitter or transponder ident
without having an antenna hooked up;
it may cause a lot of damage.
5. Ensure any loose wires with
exposed ends are protected with tape
or a suitable device so they don’t touch
each other or anything else that could
cause a short circuit.
6. Do not power up devices such
as autopilots, trim systems, flaps,
alternators or other units until they
are completely wired, and all of their
subcomponents are hooked up and
plugged in. This usually means you
A stack of avionics shown with professionally “prewired” harnesses ready to ship
to a builder. Installation errors are greatly
reduced when the stack is already wired
and tested for you.
www.kitplanes.com
An example of a radio stack mounted to its rails along with added
straps in the back that serve to better strengthen and secure the
racks together.
cannot test those items until the panel
is in the airplane.
Once you ensure that you’re safe
and ready to power up, you can move
forward by attaching the power to the
panel. If there are no sparks or smoke,
start turning on devices one at a time,
beginning with items of least importance (or lowest cost). If at any point a
breaker pops or a fuse blows, stop and
turn off all power until you can figure
out what the problem is. Once you
have successfully powered up the entire
panel, you can start programming the
various components and their interfaces
Simple nut plates on the instruments are often best for mounting various screens, but using them on the rails isn’t advisable
because you may need the future flexibility to add other devices.
such as inputting engine limitations,
airspeed reference speeds and GPS
interfaces. The more of this you can do
ahead of time, the better.
Finish Work
Now that you’ve wired and tested your
entire panel, you can remove all of the
equipment and do the finish work.
Typically, professional shops and most
builders choose to paint their panels.
Use a good quality paint, such as urethane, that will not fade or damage easily, and choose a color such as black or
cool shades of white, tan, brown or gray.
Bright colors can be distracting. Wood
overlays can look good if done properly, but other overlays available in thin
sheets such as carbon fiber are easy to
work with and can be less tedious. By far
the most popular and easiest approach is
a painted metal panel with labels on it.
You’ll find numerous options for labels.
1. Decals. This is what virtually all
professional shops use. They are thin,
mylar decals printed on a dye-sub
printer that can be output in white and
metallic. Place the decals on the panel
and cover them with a layer of clearcoat.
They will look great. Pages of these
KITPLANES June 2012
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All About Avionics continued
Labels on wires will make installation much easier no matter
which method you choose. They also assist in future maintenance
and identification of various wires.
decals can be custom ordered for $20 to
$50 per sheet.
2. Rub-on decals, also known as
Letraset. These may also be custom
ordered but are very expensive. The end
result can look nice, but rub-ons are
very difficult to apply with accuracy
over large areas, or when applying multiple words or shapes such as arrows
and lines. Pre-made sheets that you
can purchase online are a good option
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KITPLANES June 2012
Putting labels or reminders on the back of the panel will help you
remember which item is which when you are wiring it up.
for the occasional label or word, but
they may not be the best choice for an
entire panel.
3. Various online DIY decals. There
are a number of kits available that work
with varying success, but I would advise
against going this route. They do the
job, but the end result is rarely great,
and it takes a lot of time to create a
mediocre result. Go with pre-made or
custom-ordered decals instead.
Sheets of custom-made decals can be
printed on demand from your files in any
color, size or style you create.
www.kitplanes.com
Get ALL the Attention at the
Pancake Breakfast . . .
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www.SonexAircraft.com
or call: 920.231.8297
Note the simple layout of switches and circuit breakers. The valuable space in front of the
pilot is used for flight instruments and the autopilot, then radios and finally the map box
on the far right.
4. Silkscreening. This is another
DIY option you can do by ordering a
custom silkscreen and applying the
labels onto the panel. It yields a professional-looking result, but it is tedious
and somewhat expensive. Many shops
used to do this but have since moved
to decals due to the time and expense
of the process. The difficulty is that the
panel must be perfectly flat in order
to apply the silkscreen, which is not
always possible to achieve.
5. Laser-etched, laser-engraved. A
few shops online will laser-engrave your
panel. The end result can look good
with a thorough initial preparation.
This process usually entails etching
through a layer of paint into a contrasting layer below. It can be difficult with
small fonts, but it’s high quality.
6. Overlays and placards. You can
choose to have overlays made for placement around the switches or circuit
breakers and other places on the panel
from reverse-engraved or front-engraved
materials. Results are usually very good,
and costs range from $75 to $500 for an
entire panel. A number of trophy shops
can do this, but we’ve found the best
results come from Aircraft Engravers
(www.engravers.net).
7. Other DIY solutions. We’ve seen
some very good applications of office-type
labels on panels, but we’ve also seen labels
written on masking tape. Some of the
more creative solutions can be hit or miss.
Installation
When the painting and labeling are finished, reassemble your panel and install
it in your plane. The next step is to hook
up the airframe items such as lights,
flaps, ignitions, probes/sensors and fuel
pumps. This is another task best performed one wire at a time, making sure
not to string any wire too tightly. Once
everything is hooked up, repeat the
bench-test process all over again before
powering up and testing it in the airplane. Be sure to test the com radio and
transponder to ensure they are working
well before your first flight.
There is a reason professionally built
panels look good. But even if you’re
building your own, attention to detail
and high standards will create an attractive and functional panel. Stick with the
basics, and you can’t go wrong. J
KITPLANES June 2012
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