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When I was around 13 years old I was incredibly interested in cars. This was only solidified when The Fast and the Furious came out in 2001. I spent hours and hours reading magazines like Super Street and Import Tuner along with searching what was around on the internet at the time for car parts. Of course at age 13 I had no money to actually indulge in buying these parts, let alone the car to put them on - but I still built elaborate Microsoft Excel sheets that listed the car and all of the mods I would do to it. I continued to do this, even after I did finally pick up my first car - a 1964 1/2 Ford Mustang.


Well…. I once again have found myself with that same boyish desire to pull out an Excel spreadsheet and start listing out everything I would like to do to a plane before I even have the plane in my posession. I am admittedly a little further along in my plane journey than I was as a 13 year old with no money wanting a MK4 Toyota Supra. As I am writing this I am under contract on a 1977 A36 Bonanza that does not have much more done to it than the factory delivered.

The world of aviation does differ from the automotive world when it comes to making modifications to what was delivered from the factory. In the automotive world you can replace, modify, add, or remove any portion of the vehicle - pending remaining road legal per the Department of Transportation wherever you happen to live - or just treat it as an off-road or track vehicle and have more or different freedoms around modification. The same is not true for certified aircraft.

Certified vs Experimental Aircraft

The Federal Aviation Administration (FAA) deals with three types of certification:

  • Type certification - the approval of the design of an aircraft and all component parts (propellers, engines, controls, etc.) Type certification signifies the design is in compliance with applicable airworthiness, noise, fuel venting, and exhaust emission standards.
  • Production certification - the approval to manufacture duplicate products under an FAA approved type design. Production certification signifies than an organization and its personnel, facilities, and quality systems can produce a product that conforms to its approved design.
  • Airworthiness certification - signifies that an aircraft meets its approved type design (if applicable) and is in a condition for safe operation.

These three types of certification are covered in the Code of Federal Regulations (CFR), Title 14, Part 21

Certified Aircraft

Aircraft manufacturers, like Beechcraft/Textron Aviation, went through the process of designing an aircraft, building an aircraft, getting the design/implementation of that aircraft a type certification from the FAA, then proceeded to get a production certification to build more than that single instance of that aircraft, and each aircraft when coming off of the production line was granted an airwirthiness certification.

Experimental Aircraft

There are other avenues for taking to the sky. You can in fact build your own airplane according to your own design, build an airplane from a kit, or buy an airplane that someone else has built from their design or from a kit.

Amateur Designed & Built Aircraft

When building a plane from your own design - the plane will not have a type certificate, and the production certificate is likely not applicable.

Amateur Built Kit Aircraft

If you choose to build a plane from a kit (I do hope to do this someday) - like an aircraft from Vans Aircraft - Vans will hold a production certification to produce the kits, but no type certification.

In any experimental aircraft however, an airworthiness certification must be obtained.

Modifications to Certified Aircraft

If an unapproved modification is made to a certified aircraft, that aircraft simply becomes unairworthy - unable to fly entirely. There are ways to regain this airworthiness, but it’s typically a long, expensive and arduous process.

Modifications to Experimental Aircraft

If a modification is made to an experimental aircraft - and only if that modification changes flight characteristics - the aircraft will likely have to undergo flight testing again to regain it’s airworthiness certification.


Certified aircraft can only remain airworthy if approved modifications are made. Experimental aircraft can make many changes, and only changes that alter flight characteristics would require recertification to remain airworthy.

What is an STC?

The above explanation is a detailed explanation to state that unless a modification is approved on a certified aircraft - it cannot be done. This is where Supplemental Type Certificates commonly called STCs come into play. A Supplemental Type Certificate is a type certificate that is issued by the FAA when approval has been given to modify an aeronautical product from its original design. STCs add to an existing type certificate, and as such STCs are produced for specific aircraft.

A36 Bonanza STCs

A question I have seen many times in forums, and something I am finding is not really available and consolidated is a list of STCs available for A36 bonanzas. In doing my research to build my ideal Bonanza in my Excel file I have run across many, and hope I can begin to create a place of reference that may help others. I do hope to keep this updated as I find more.

STC Description
D’Shannon Gross Weight Increase Gross weight approval that allow gross weight to be increased to 3,850 lbs without tip tanks, and 4,010 lbs with tip tanks. Requires: IO-550 STC, Baffle Cooling Kit.
D’Shannon Engine Conversion - IO-550B The objective is a more powerful, more efficient and reliable engine; while increasing the value of your aircraft; provide greater speed; faster climb; greater maneuverability; a better service ceiling; and greater carrying capacity.
D’Shannon Engine Cooling Baffles D’Shannon Baffle Cooling Kits help avoid cylinder replacement by reducing valve, valve guide and overall engine wear by providing optimal cooling.
Scimitar Propeller Update to replace obsolete Beech, Flottorp, McCauley threaded props, and steel-hub Hartzell propellers. Upgrading from a two-bladed propeller, or any other propeller.
D’Shannon High Performance Exhaust Available for the IO-550, IO-520. Beechcrafts exhaust system for the IO-550 and IO-520 was originally designed for the IO-470 engine with 260hp. This is one of the main reasons the engines of today do not generate all of the horsepower they are capable of producing. The D’Shannon system takes full advantage of the available horsepower in the engine, allowing the engine to breathe more efficiently and relieve undue stress on the engine and internal parts. Potential fuel savings, allowing same performance with lower consumption. By providing dual heat collectors (one on each side of the engine) improved defrost and cabin heat is provided.
D’Shannon Tip Tanks D’Shannon Aviation auxiliary tip tanks give you the added range and safety of 40 additional gallons of fuel. Enhanced stability, lower stall speed and increased aileron authority for safer operation and smoother ride. Tip tanks enhance overall stability, improve spin characteristics and lower landing and stalling speeds at the aircraft’s original gross weight. Or take advantage of the FAA approved gross weight increase, which you can in either added fuel or cabin weight.
D’Shannon Vortex Generators D’Shannon Aviation’s Vortex Generator System is a simple way to improve the low-speed handling and margin of safety of your Beechcraft. D’Shannon V/Gs give you: A lower stall speed - for safer landings and maneuvering flight, increased aileron authority at lower speeds for better control. All 36 Bonanzas are approved with a 100 lb. gross weight increase.
D’Shannon Gap Seals D’Shannon’s Gap Seal Kits for Bonanzas and Barons offer great improved performance without a great deal of cost. Benefits of D’Shannon gap seals include: Reduced stall speed, decreased drag and increased cruise speed, shorter takeoff and landing distances, improved control authority under all flight conditions.
SpartSpace Baggage Conversion The SmartSpace baggage conversion installs behind the rearmost passenger seats in the Beech A36 (pre-1979), adding approximately 8 cubic feet of storage area, while retaining the existing hat shelf area for easy in-flight access to smaller objects. The SmartSpace baggage conversion has a footprint similar to post-1979 A36 aircraft and is certified for the same 70lb maximum loading capacity (C.G. Envelope limits must be observed).
True Blue Power Lithium-ion Battery Less Weight. Less Maintenance. More Power.
GAMIJector & turboGAMIjector GAMIjector® fuel injectors and TurboGAMIjector® fuel injectors are fuel injection nozzles designed to deliver specific amounts of fuel to each individual cylinder that will compensate for the fuel/air imbalance inherent in the fundamental design of the engine fuel/air systems. Each GAMIjector® fuel injector is carefully calibrated to much tighter tolerances than standard fuel injectors available for your engine. GAMIjector® fuel injectors alter the fuel/air ratio in each cylinder so that each cylinder operates with a much more nearly uniform fuel/air ratio than occurs with any standard factory set of injectors. Some models may be eligible for a gross weight increase from 180-300 lbs depending on the engine. To qualify, the airplane must have an IO-550B and GAMIjector calibrated fuel injectors and the LiquidAir Baffle kit.
GAMI LiquidAir Baffle LiquidAir Baffle Kit replaces specific elements of the existing Beechcraft baffling and adds additional flow through the addition of fuselage side louvers. Aerodynamic design smooths airflow into engine compartment, reduces drag and directs cooling air properly to cylinders.
GAMI Osborne Tip Tanks This is a transfer pump system. Fuel is transferred from the tip tanks into the main tanks by an electric fuel pump mounted in each wing. All of the tip tanks come with some gross weight increase.
B&C BC410 Standby Alternator System This system provides 20 amps of power to support continued flight in the event of primary alternator failure. Once activated, it operates in the background, automatically signaling its operation to the pilot through a panel-mounted annunciator light (which also doubles as a standby alternator load monitor). If the primary alternator fails in flight, the controller will sense the drop in system voltage and automatically activate the standby alternator. If the current requirement is over 20 amps when the standby alternator is activated, the annunciator will flash. Reducing the current usage to 20 amps or less will cause the annunciator to cease flashing and illuminate in a steady state. The pilot may choose equipment needed for the given flight conditions by simply keeping the total load below the flashing point of the annunciator. This will reserve battery energy for transient loads, (gear, flaps, landing lights, etc) during approach. Loads may be beyond the flashing point of the annunciator for up to five minutes without damaging the standby alternator.
Tornado Alley Turbo Whirlwind III The Tornado Alley Turbo Whirlwind III™ Bonanza is the finest turbonormalizing package available for the IO-520 or IO-550 Powered Bonanza today. The turbonormalized Whirlwind III™ not only provides sea-level power up to 20,000 feet but also significantly improves low altitude (less than 12000’) speeds as well. With the “magic” of turboGAMIjectors® fuel injectors, the Whirlwind III™ bonanza will fly faster; and faster on less fuel, with cooler engine temperatures than normally-aspirated Bonanzas.
Colemill Starfire The Starfire modification includes: New Continental IO-550B 300 horsepower – for more speed, better climb and reliability, new Hartzell 4-blade “Q-Tip” propellers with Woodward governor for an extremely quiet, vibration-free ride, Shadin Digiflow fuel computer – for extremely precise fuel management, all new accessories, hoses and belts – for hours of trouble free service.
TKS Ice Protection TKS fluid exudes from aircraft leading edges