Why Aircraft Modifications Aren't Like Car Mods (And My A36 Bonanza Wishlist)

Some habits never die.

At 13, I was obsessed with cars - an obsession that The Fast and the Furious (2001) only amplified. I spent hours reading Super Street and Import Tuner, building elaborate Excel spreadsheets of modifications for cars I couldn’t afford. MK4 Toyota Supra was the dream, complete with every bolt-on imaginable meticulously researched and priced.

Flash forward to today, and I’m doing it again. Same boyish excitement, same Excel spreadsheet obsession, but this time it’s aircraft modifications. The difference? I’m actually under contract on a 1977 A36 Bonanza - a factory-standard bird just begging for upgrades.

Here’s where aviation gets complicated. In the automotive world, you can modify anything as long as it remains road legal - or just build a track car with complete freedom. Certified aircraft? Not so simple.

The FAA’s Three-Tier System

The FAA controls aircraft through three levels of certification:

• Type Certification - Design approval for the aircraft and every component (engines, props, avionics, etc.). Think of it as the blueprint getting government approval.
• Production Certification - Permission to manufacture aircraft based on that approved design. Quality control meets bureaucracy.
• Airworthiness Certification - Individual aircraft approval proving it matches the type design and is safe to fly. Your specific plane’s birth certificate.

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

Certified Aircraft: The Corporate Path

Beechcraft/Textron followed the full process: design approval, production approval, individual aircraft certification. Every Bonanza that rolled off the line has government blessing at every level.

Experimental Aircraft: The Builder’s Path

Multiple routes to experimental certification:

• Scratch-built from your own design (no type cert needed)
• Kit aircraft like Van’s Aircraft builds (kit manufacturer has production cert, but no type cert)
• Buying someone else’s experimental

All still need individual airworthiness certification, but the path is different.

The Modification Reality Check

Certified Aircraft: Unapproved modification = grounded aircraft. Period. Getting airworthiness back is expensive and painful.

Experimental Aircraft: Modify freely, but flight characteristic changes require new testing. Much more flexibility.

Enter STCs: The Certified Modification Solution

Supplemental Type Certificates (STCs) are the key to legally modifying certified aircraft. Think of them as FAA-approved modification kits that supplement the original type certificate. Each STC is aircraft-specific - no universal solutions.

My A36 Bonanza STC Research

Forum posts constantly ask: “What STCs are available for A36 Bonanzas?” I couldn’t find a consolidated list anywhere, so while building my dream Bonanza Excel spreadsheet (yes, really), I’ve compiled every STC I could find. Consider this a living reference for fellow Bonanza dreamers.