Sonex Cabin & Panel Design

I have been asked by several current builders to share some of my tips and tricks on the building of my cabin / panel. For all the current and future builders this blog is to assist you in your journey and build. These are my personal tips, with no affiliation to the Sonex Corporation. Please feel free to use these tip, documents and files as you begin your building journey.


Always will display the proud American flag!


The Background: I purchased my kit used with the air frame mostly built. The interior was blank which allowed me to design a cabin to fit my exact needs. Working with my wife, AI and avionics expert, we set out with the goal of designing a simple, fully functioning panel / interior for our needs.


Our Needs: To have an aircraft we can travel cross-country in, remain comfortable, and look great while providing inherent redundancies, safety measures and a work stream that would minimize cockpit distracts.

The Challenge: Everything is a give and take. The more you add the more weight, complexity, clutter and risk you induce into the plane. For us, to achieve our cross-country goal, we chose to add:

  • Autopilot
  • ADS-B in / out
  • Aux Fuel tank (6.5 gal with optional 11 gallon upgrade) (Separate blog post)
  • Interior / Exterior lighting for Night flying
  • Dual independent synthetic vision screens
  • Dual moving maps
  • Battery backup on secondary EFIS, weather, traffic and radio
  • Backup radio with nav features on independent antenna
  • Air conditioning (Separate blog post)


The benefits of the final design

  • Built-in Checklist (Just work the switches from left to right for take-off, right to left for landing)
  • Headset wiring completely removed from the cabin area
  • Glare free screens being placed vertical
  • Color coded switches to create redundancy in labels
  • A complete loss of engine/battery still allow for 3 hours of synthetic vision, weather, traffic, navigation, radio
  • Simple and elegant cockpit
  • Maximized breaker-switches to minimize wiring, panel space and complexity
  • Breakers or breaker switches on each electrical item
  • Audio inputs and charging for music, video, alerts, iPad, traffic


Before you begin your design, think about your goals and missions. Then plan for those by ensuring your weight & balance, amp load will be met.

The general layout is set up with primary EFIS and secondary in far left positions so the pilot has airspeed and altitude in line of sight during critical phases of flight. The sub panel makes entering the aircraft a little more difficult if you are over 190lb and 6’ in height, but significantly improves the panel layout function.

The iPad is running Garmin Pilot with safe taxi, weather, traffic, terrain, synthetic vision, etc. It is the primary navigation system and backup flight instruments. The app is paired with the Garmin GDL-39 3D ADS-B in unit with battery backup and hard-wired to a breaker on the panel (GPS breaker). This keeps the GDL charged but immediately activates battery backup if power is disabled. This ensures that if I lose total aircraft power, the Garmin pilot can be used for navigation and synthetic vision.


The MGL discovery light manages the primary flight instruments, com radio, remote transponder, auto pilot and engine monitoring.


All antennas are mounted to the glare shield (MGL WAAS, Garmin WAAS, Garmin ADS-B).


General Building Tips:

  • Mount the ELT remote switch behind the rear bulkhead to save panel space
  • Mount the headset jacks to keep all wires out of the cabin and also save panel space
  • Group breaker switches by function: system, avionics, lighting, misc.
    • Order them in checklist order
      • Batt master on, Mag on, secondary on, check master fuse…then start
      • Same for lighting
      • Separate Autopilot and aux fuel functions from all others
    • Hardwire iPad and other devices to their own breaker so they continually stay charged
    • Used matte black vinyl to clean up glare shield
    • Used carbon look vinyl to make panel and accessories look smooth and clean
    • Vertically mount EFIS / iPad to eliminate / reduce glare
      • Did not make entire panel vertical to keep space more open and comfortable
    • Keep non-essential switches, functions, instruments to right side of panel
    • Label the backside of your panel for reference later or during wiring
    • Use a 2-sided grounding block (firewall-cabin) so each electrical wire has its own common ground to reduce/eliminate back-feed/interference

Now on to the fun stuff…details and pictures:

Remote headset jack bracket – keeps jacks and wires out of the cabin. Also protects jacks from being knocked or bent.


Remote ELT switch – frees panel space, frees wiring needs, isn’t used during flight and accessible in the event of a crash.


  • A sub panel or placing switches/breakers in a row can allow you to leverage bars instead of wires to power groups of breaker-switches. This will reduce wiring by 50%, reduce the risk of failure and reduce weight. (Note: I highly recommend aviation wiring only: for safety and FAA inspection)



Create the perfect indirect cabin lighting by using red LED post lights (I use two from aircraft spruce). Completely lights up the cabin without hurting your eyes. This took me over 30 hours to get right and worth every minute. The acrylic canopy will radiate the light from behind and glows throughout the cabin without impeding any outside visibility. Link to item


Leverage an EarthX battery to save weight, mount on its side for easy access and easy install with the EarthX factory battery bracket. Then make a simple bracket to put the master relay on top of the bracket to significantly reduce large gauge wiring and complexity. Mount of left side right behind starter.


Create built in access panels for wingtip lighting. I used .032 T-6061 aluminum to create a simple plate to mount my Nav light on. The lights are Knutzelman LEDs and they sell Sonex specific brackets. Leveraging LED lighting throughout will minimize AMP requirements. Use nut plates for easy removal and access during annual inspections or for maintenance.


To reduce heat, noise and finish off the interior, I purchased 4 door mats from home depot (black with rubber back) and cut them to fit onto the firewall and floor.


I hope some of these tips help you and your panel design! 



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