Radios, Autopilot and Instrument Panel

Prior to purchasing the Spartan, I owned a Mooney Ovation and before the Ovation, a Mooney MSE. Both airplanes had identical King avionics packages that included: HSI, A/P, KMA 24 Audio Panel, KX 155 NavComm (#2 radio), and KT76A Transponder.  They also had a Garmin 530 as the primary radio, a digital fuel flow system and a P2 Audio Advisory System.

When it came time to upgrade the radio package in the Spartan, I was able to have the identical King HSI, KMA 24 Audio Panel, KX 155 NavComm (#2 radio), and KT76A Transponder, as well as a Shadin Fuel Flow System and P2 Audio Advisory System.  For the primary radio, I went with an upgraded Garmin 530 with WAAS and Terrain capabilities.

The autopilot was more of a challenge.  The only autopilot ever certified for the Spartan Executive was the Brittain B5C, a pneumatic three axis system. Although the company still exists, they stopped building new autopilots many years ago. Adding to the dilemma, none of today’s autopilot companies have an interest in obtaining an STC for the Spartan because the market potential doesn’t justify the investment. After a number of discussions with the folks at Brittain, they agreed to build a “new” B5C three axis autopilot system if I could locate two key components – – the mode selector box and a specific model Brittain turn coordinator that is the guts of the autopilot. After a bunch of phone calls to friends in the aviation community, I managed to locate the necessary components within a day.

There was one other challenge associated with the avionics and autopilot upgrade.  When the panel was last updated in the mid-1970’s, airline style radios were used.  That means the primary radios were 5 inches wide versus the normal 6-3/8 inches width for modern avionics.  The entire panel had been designed around the existing radios, so a completely new instrument panel would need to be designed and fabricated to accommodate the new equipment.

The following pictures and explanations will take you through much of the entire upgrade process.

Although the original panel was attractive, the primary radios were non-standard in size and other radio components were installed wherever the necessary space existed.  Because the interior would ultimately be blue, the existing colors of the original panel would need to be changed.




The first step in the process was to acquire all of the necessary radio and autopilot components, followed by building the necessary wiring harnesses.  The autopilot system has more individual components than everything else combined.  Note the 6 new individual pneumatic servos – – they have consecutive serial numbers.

Autopilot Components

BrittainB5CPackage 004

BrittainB5CPackage 006

Next was building the wiring harnesses. Fortunately, Brittain had provided the primary harness for the autopilot components.

Wiring Harness Construction

Wiring Project 002

Wiring Project 005

Wiring Project 007

Finished Wiring Harness

Wiring Project 010

Autopilot Harness

Wiring Project 004

Because of the age and nature of the equipment, some components were mounted in the instrument panel and others were located in the rear of the airplane.  There were approximately 75 wires running between the front and rear components.

Removal of the Old

Radio and Autopilot Project 002

Radio and Autopilot Project 004

Radio and Autopilot Project 003






Final Result With The Tan Interior


Current Panel Appearance With The Blue Interior