Modernizing a Shrike Commander
Dayton - Wright Brothers Airport
10570 Springboro Pike Miamisburg, Ohio 45342
Phone 888-881-5580 937-885-5580 Fax 937-885-5586
Web commander-aero.com
email service@commander-aero.com
Modernizing a Shrike Commander
John Bosch and Gary Kromer
Commander Aero had the unusual opportunity to
purchase a Shrike that it had maintained for the past
15 years. It was as if we had owned the airplane
because it was always in our hangar and we had the
opportunity to give it plenty of TLC. When the
owner transitioned to a turbo Commander he
advertised for bids and Commander Aero was the
successful bidder.
Since the Shrike only had 2,700 hours TT and
we knew that it was a solid airplane we had our
hearts set on turning it into a modern airplane while
retaining its classic attributes. From a project
planning viewpoint we separated the project into five
main categories.
the airplane we had the test rerun. The test showed
that we had a 36-month spar. After testing again with
another company the results showed a 30-month spar.
With this uncertainty we decided to replace the spar
and eliminate the requirement for further testing.
Fortunately we had experience replacing spars and
had all the fixtures and skills to do the job properly.
Major Tasks
Aerodynamic Enhancements
Avionics / Electrical Systems
Special Features
Final Dress-Up
Russ Topp removing lower spar cap
Jerry Cornett starting work on N741CA
Major Tasks
Three major tasks where identified that needed to be
accomplished early in the refurbishment project.
These were 1.) Spar replacement, 2.) Engine
overhauls, and 3.) Gear inspection and overhaul.
Spar Replacement
A previous inspection resulted in the spar being
identified as a 12-month test interval instead of the
normal 36-months. After Commander Aero acquired
Scott Shaw positioning new lower spar cap
As a point of interest when the spar was removed
from the airplane we examined it and found no
evidence of corrosion. The testing procedures and
equipment apparently are not able to differentiate
between a good spar and one with defects or
corrosion. Replacing the spar is a big job which is
made even more difficult since it is necessary to
remove the engines, engine mounts, landing gears,
fuel cells, and the interior of the cabin.
The Magnum Overhaul should be called a
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new parts are installed than one would expect for an
overhaul. The owner of Magnum Engines, Gene
Svoboda is a perfectionist who keeps his shop as neat
as the engines are at time of delivery.
Russ Topp riveting the spar cap in place
As part of the spar cap replacement task an
inspection was made of the skins that were removed
to determine if there was any evidence of corrosion.
Where there was corrosion no matter how small the
skins were replaced. We also replaced all fuel cells
and installed new lift and turn fuel caps.
Jerry Cornett performing SB222 on engine mounts
New skin panels being installed
Engine Overhaul
CAI had the engines overhauled by Magnum Engines
which is located within a few miles of Commander
Aero. Their work is of the highest quality and it is
convenient to transport engines from our hangar to
their facility.
Magnum engines are flow-matched at the
cylinders and fuel system to assure that the
combustion chambers receive an equal amount of
fuel for optimum performance. Also the engines are
dynamically balanced with the latest state-of-the-art
computerized balancing equipment.
While the
engine is being rebuilt all engine components such as
starters and oil pumps are sent to FAA approved
specialty shops for overhaul.
All new Lycoming cylinders were installed after
they were polished and flow-matched. All new hoses
were installed from the firewall forward and the
baffling and brackets were repaired or replaced. In
addition all wiring from the firewall forward was
replaced.
Engine and engine mount ready for installation
Gene Svoboda, President of Magnum with N741CA Engine
The engine mounts were inspected in accordance
with SB 222, treated and painted to look like new.
The inside of the cowling was also treated and
painted. The final appearance of the installed engine
made the airplane look even better than when it was
brand new.
Russ Topp mounting the engine
Landing Gear Inspection
Everyone who is familiar with twin Commanders
appreciates the rugged construction of their landing
gears. Little maintenance is required in order to
The nose wheel gear actuator was rebuilt with a
CAI seal kit and leak checked. The landing gear and
wheel wells were painted making the gear assembly
and wheel wells look like new. For final dress-up the
original decals were installed making the gear look
like the airplane was just being rolled out of the
factory.
New tires were mounted as well as new bungee
Dick Kaercher cleaning gear components
obtain reliable performance. But like any other
mechanical component the gear and wheel wells are
subject to wear and corrosion. We performed the
3000-hour landing gear inspection and replaced worn
bushings and removed corrosion from the inside of
the wheel wells and the landing gear components.
cords. The landing gears were actuated multiple
times to assure proper clearances between the gear
mechanism and wheel wells.
Gear components ready for paint and assembly
Aerodynamic Enhancements
There are two areas where aerodynamic
improvements were made 1) installation of flap gap
seals, and 2) installation of AeroDyne winglets.
Flap Gap Seals provide early payback
From strictly a performance and financial viewpoint
the best modification that an owner can make to his
piston Commander is to have flap seals installed.
They are known to increase cruise speed by about 7
knots.
This translates into a payback in
approximately 250 hours flying time.
Their
advantage is that an area of drag is converted to an
area of lift.
Commander Aero produces its seals in
accordance with its STC SA1566GL. We also have a
PMA (Parts Manufacturing Authority) that provides
us with approval to sell flap gap seal kits for other
repair stations to install. We have many
endorsements from owners attesting to the higher
cruise speeds they have after installing flap seals.
Bob Hoover had us install them on his Shrike and he
became our best salesman. Bob was very pleased
with the higher speeds he had with the gap seals and
was pleased to give us permission to use his name as
an endorsement.
Winglets improve appearance
The advantage of winglets on a 500S is primarily
in the area of improved handling characteristics and
better single engine performance. They also improve
the appearance of the airplane.
AeroDyne winglet with recognition light
Flap Gap Seals installed on the underside of N741CA
AeroDyne Winglets improve handling
The winglets were installed with recognition lights
and strobes. As most pilots know winglets reduce
drag at the tip of the wings. The amount of drag is a
function of the angle of attack. For piston aircraft
flying at lower altitudes the angle of attack is
relatively low making the reduction in drag less. For
aircraft flying at high altitudes where the air is
thinner the angle of attack is greater which makes the
benefit of winglets greater.
Aerodyne winglet installed on N741CA
Most owners who retrofit their airplane with
AeroDyne winglets purchase them with recognition
lights. This is an important safety feature that
provides an excellent outline of the aircraft.
Avionics / Electrical Systems
Avionic Upgrades
Most of the excitement in general aviation today is
the result of the latest advancements in navigation,
weather and traffic/terrain awareness. Our customer,
like so many other general aviation pilots, wanted to
take advantage of these advancements. Flying is so
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To begin the avionics upgrade project the entire
panel was removed. All extraneous wiring and nonessential equipment was also removed. Not only was
there a weight saving from this effort but the
installation was much cleaner and future work easier
to analyze because there is no confusion from unused
wire bundles.
All wiring and hoses were provided with service
loops so the instrument panels could be tilted out at
top for easy access behind the panels.
Complete gutting of the panel
Building a mock-up of the panel
At the same time that used wires were removed
all hoses in the cockpit and cabin area were replaced
with new hoses.
Any of the instruments that remained were sent
to instrument repair shops for overhaul and
certification. With this approach the complete panel
could be considered new and there was confidence
that the instruments were operating properly.
While working in the cockpit area the pilot and
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ecleaned to look like
new. The control columns were covered with the
same leather used for lining in the cabin.
Designing the panel
The panel was designed with special software making
it possible to quickly go through several iterations
with the customer before arriving at the final layout.
The autocad software was then sent by email to a
local shop that cut out the aluminum panels with an
automated laser machining center. Including the
overhead panels there were a total of nine panels.
After fitting checks the panels were painted and silk
screened prior to installation.
To optimize the panel during night flights Nulite
wedge lighting components were installed for all the
major instruments. This reduced clutter as well as
making the instruments uniformly legible.
Preparing internal wiring
Checking for panel fit
All new harnesses were made and there was no
splicing of existing wiring that could cause a problem
in the future. The objective was to have the same
level of integrity in the entire electrical system as one
would expect from a new airplane fresh from the
production line. To help with future maintenance
tasks communication jacks were installed aft of the
baggage compartment so a technician in the avionics
bay could talk to a technician in the cockpit. This
facilitates
making
voltage
adjustments
or
troubleshooting avionics systems.
Tim Bench making harnesses
Pilot panel and center console
Co-pilot panel and center console
To get the benefit of the latest avionic technologies
the customer asked us to install dual Garmin GNS
480’
s
, a Garmin TIS transponder, and a Castleberry
flight director that we connected to the new S-Tec
60-2 autopilot with altitude pre-select and GPS
steering.
Switches were added to the overhead panel for
strobes and recognition lights located within the
AeroDyne winglets.
The list of avionics is impressive:
New Garmin AT MX20 with Traffic & Chart View
New Garmin AT Dual GNS 480 WAAS
GPS/NAV/COM Systems
New Garmin GTX 330 TIS Transponder
New Garmin AT SL70R Remote Transponder
New Garmin GMA340 Audio Panel with Marker
Beacon and 6-place Intercom
New S-Tec 60-2 Autopilot w/ GPSS steering,
ST-360 Altitude Pre-Select & Flight Dir.
New EII Digital/LED Engine Gauges
New L3 WX 500 Stormscope
New WSI InFlight Weather
New SHADIN ADC 200
New SHADIN DIGIFLO fuel flow system
New Custom Instrument Panels with Silk
Screening
New Nulite Wedge Lighting
Plus
RDR 2000 Stabilized Color Radar with
Vertical Profile (Displayed on MX20)
Collins HSI
Insight Gemini Engine Monitoring System
Davtron Clock
Smaller light bulbs were used for the annunciator
function to save space and also to make the panel
look modern.
Flight Safety Priority
Safety of flight was a priority in the selection of
systems and the design of the panel.
With
advancements in avionic equipment every effort was
made to overcome and avoid problems with weather,
traffic, terrain and the possibilities of instrument or
electrical failures.
Center console
With this in mind the following selections were made:
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Traffic Avoidance - Garmin TIS system
Weather
Bendix RDR 2000 Radar
L3 WX 500 Stormscope
WSI In-Flight Weather
Garmin AT MX20 moving map & MFD with
terrain displayed
Fuel Management
Dual transponders for redundancy
Emergency avionics bus
Whelen 3-light strobe system –Comet flash
Annunciator warning system
All pilots are aware that weather is the major
factor in flight safety and knowing the weather ahead
is critical. To get this information the owner selected
radar for detecting precipitation from a horizontal
view, a Stormscope to detect electrical discharges
from opposing air currents, and satellite weather to
observe weather patterns from a vertical view. These
displays along with visual observations will give the
very best information about the weather.
Special Features
The owner of N741CA wanted five special features
for his airplane. 1.) TKS De-Icing system, 2.) TurboCharging, 3.) Built-In Oxygen System, 4.) Extended
baggage compartment, and 5.) Engine, Battery and
Cabin Heaters.
Only one choice exists for the pilot while
operating the ice protection system: anti-ice or de-ice
mode. In the anti-ice mode, a protective film of
glycol prevents the formation of ice. In the de-ice
mode, the glycol chemically breaks the ice bond. A
significant feature of both modes is the elimination of
run back ice.
TKS De-Icing system
The owner had previously owned a Bonanza with the
TKS weeping wing de-icing system. He really liked
it and wanted the same system for his Shrike.
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Russ Topp installing the TKS leading edges
Porous, laser drilled titanium panels are installed
on the leading edges of the wings, and horizontal and
vertical stabilizers. A slinger ring is installed on the
propeller and a spray bar is positioned on the
windshield for protection. A glycol based fluid is
exuded through the panels and flows over these
surfaces keeping the aircraft virtually ice free.
The weight added to an aircraft as a result of the
TKS ice protection installation is minimal. The TKS
system weights approximately 40 lb without fluid
(lighter than a rubber boot system, if one was
available) and approximately 100 lbs with a full tank
of fluid.
The attractive TKS system requires a minimum
of upkeep. As the system is used, it flushes out any
accumulation of debris on the panels. Glycol, the
main ingredient of the ice protection fluid, has
cleaning properties and will not harm the paint finish
on the aircraft.
Filler Cap for De-Icing Fluid
The glycol based fluid is metered from a tank by
a small electrically driven pump through a microfilter to proportioning units. The proportioning units
contain calibrated capillary tubes which apportion
fluid to the individual panels and the propeller slinger
ring. The windshield is protected with an on-demand
pump and spray bar. A significant advantage for the
pilot is the simple operation of the system. Just turn
the system ON when icing is encountered and OFF
when leaving icing conditions.
TKS leading edges on the tail
There is absolutely no loss in aircraft
performance as a result of installing the TKS system,
yet significant anti-ice and de-ice capabilities are
added. Up to 3.0 hours of continuous anti-ice
protection is possible with a full tank of ice
protection fluid.
The placard “
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Turbo-Charging
Because the owner would be flying over the Rocky
Mountains he wanted the engines to be turbocharged. After evaluating what was available the
Merlyn Products turbo system was selected.
Merlyn Products Turbo System
Seeing a need to replace the old turbo systems of
the past, Merlyn Products has provided the Twin
Commander 500B, S, and U owners with a new
alternative for gaining performance from their current
E1A5 or E1B5 engines.
The turbo-normalized system uses a single high
efficiency Garrett turbo per side providing a full
290HP at 18,000 feet. Airspeed is 190KTAS at
12,000 feet and 70% power. Single engine service
ceiling is 14,000 feet and takeoff and climb
performance is improved. Fuel flows are unchanged
and there are no scavenge pumps and no operating
limitations. The kit includes new exhaust, hoses, and
induction tubes.
Incorporation of the STC
(SA01142SE) is available with a 250lb gross weight
increase.
Built-In Oxygen System
The built-in oxygen system provides convenience
and looks first rate in the all leather interior. The
system is extremely easy to use. The regulator is
located where it can be reached by the crew or
passengers in the forward part of the cabin. After the
supply cylinder is opened the masks may be
connected to the outlet ports. The large knob on the
regulator is a
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remember not to smoke while oxygen is in use and to
turn off the flow of oxygen at the regulator before
disconnecting the masks from the outlet ports. The
supply cylinder is located in the aft fuselage adjacent
to the avionics racks.
Complete new exhaust is above the engine
Merlyn has taken advantage of advancements in
turbo charging systems by producing a kit that is
efficient, lightweight, and simple. And does it ever
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Oxygen regulator and outlet shown above
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The crew and passenger masks are stowed
conveniently in the cabin for use whenever flying at
higher altitudes. Oxygen outlets are next to each seat
for six occupants.
Turbo is mounted aft of the engine
Extended Baggage Compartment
The owner is a sportsman who has many interests
including skiing. To carry his skis he wanted an
extended baggage compartment. This is a feature
that we have provided for other customers by
enclosing space from the current baggage
compartment back to the battery bay. This increases
the baggage compartment capacity from 27.1 ft.3. to
38.2 ft.3 for a 41% increase. Perhaps even more
important it provides a space for stowing items like
skis or rifles that are up to 6 feet in length. The
baggage compartment and the extended portion are
lined with gray leather and the floor is carpeted.
Engine, Battery and Cabin Heaters
With the owner living in Minnesota there is need to
have heaters for winter flying. Most importantly oil
heaters were installed on the engine sump and the
cylinders plus the batteries are wrapped with a
heating pad. For the comfort of the crew and
passengers electric heated mats are placed on the
carpeted floor to warm the cabin.
An external power jack is conveniently located
next to the battery compartment.
External power connector and battery compartment
Interior of baggage compartment
Just inside the baggage compartment in the upper
right hand corner are lights that show the Tanis
heaters are on. Separate lights are for LH engine, RH
engine, battery, and cabin. Below the lights is a
switch to turn off the cabin heat. This is important if
a remote airport has limited electric current the
priority is to heat the engines and battery.
Final Dress-Up
Extended portion of baggage compartment
To make it easier
to place long items in
the extended portion
of
the
baggage
compartment
the
baggage door hinges
were changed from
being on the forward
side of the door to the
upper side of the door.
FAA approval was
granted to make the
alteration.
An air
cylinder was used to
lift the door after it is unlatched and a light on the
door illuminates the area in front of the door to make
loading and unloading luggage at night an easier task.
The lights internal to the baggage compartment and
the one on the door turn off when the door is closed
and latched.
With the objective of making N741CA the best
Shrike in the world there was no item too small for us
not to make it the best possible. With this in mind
everything was done to make each function and part
be exceptional. This was important not only from an
appearance point of view but also from a
convenience and usefulness consideration.
Fresh JetGlo paint on N741CA
Exterior Paint
The airplane was painted by Cimarron of El Reno,
OK. The paint scheme was selected by the owner
that features a double gold strip and cream
background.
NASA Foam seat cushions
Arm rest in the middle of the rear bench seat
Cabin Interior
While attending a NBAA convention considerable
time was spent selecting leather goods for the cabin
interior. A high-quality leather material was chosen
that is intended for the best executive jets. There
were two thicknesses of leather selected. The thicker
material is for the seats and the thinner material is for
the side and top liners.
For carpeting a fire retardant fabric was chosen
of a dark gray that complements the lighter gray
leather seats.
Before the final installation of the interior we
applied a super sound proofing material and
membrane to keep the cabin as quiet as possible.
Seat Cushions and Seat Belts
For the ultimate in comfort NASA foam was used for
the pilot and copilot seat cushions. To help keep the
cockpit organized during flight storage pockets were
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copilot seats.
Shoulder belts for the pilot and copilot are
included along with lap belts. In addition to belts for
the crew there are 5 lap belts for passengers, 2 for the
rear facing seats and 3 for the rear bench seat.
For the comfort and convenience of passengers a
large arm rest is provided between the seats on the
rear bench. As with most arm rests it can be lifted up
to make space available for a third person to sit in the
middle of the rear bench.
Entertainment Jacks
Entertainment Jacks
Each seat has a panel for entertainment and
communication jacks. Passengers have the ability to
listen to the crew talking to ground control or to talk
to the pilot. They also have the ability to listen to
music from the entertainment jack by bringing along
a CD player or other recorded music player.
Storage pocket i
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Personalized Gust Lock
Commander Aero is an advocate of always using a
gust lock when a Commander is on the ramp. With
this in mind CAI designed its own gust lock to be
easy to install and remove. This is done with one
hand while standing on the ramp.
Passenger amenities
Convenience Features
Opposite each seat there are air outlets, individual
lighting and an adapter for oxygen masks. The
creature comforts and cabin interior were planned to
be similar in luxury to a Citation.
N741CA Ready for Take-off
Commander Aero has much pride in N741CA and
feels grateful for the opportunity to have worked with
Dr. John Trusheim who is the owner. His desires for
additional features helped make N741CA the
exceptional airplane that it is. Together we have set a
new standard for modernizing twin Commanders.
Stow-Away table
If passengers want to write a note, use a laptop
computer, have a snack or play cards there is a
convenient stow-away table available.
About the authors
John Bosch is president and Gary Kromer is service
manager at Commander Aero. For more information
on these upgrades or other information contact Gary
or John at 888.881.5580.
Rudder Gust Lock