R4D-6/DC-3 Part 91 IFR-Certified Bendix King Autopilot and Garmin GPS Installation

The following glare-screen-mounted Bexdix King autopilot and GPS installation was made so that single-pilot IFR flight in challenging weather would be practical using Jeppesen chart routes and procedures that are used in today's complex instrument navigation environment. During some phases of flight, especially when making non-precision instrument approaches, it is impractical to use Sperry autopilot or to accurately hand-fly the frequent changes of heading, altitude, and airspeed in turbulent clouds, while often changing com and nav frequencies and VOR bearings, and while also toggling between the pilot and copilot panel VORs to monitor approaching fixes.

This modification is only for those who do not want to alter the original panel and who are only certified for FAR Part 91 general aviation operations. To be certified for Part 135 commercial air carrier operations, more modern avionics are required that will require cutting into the panel and making extensive modification. This certified air carrier modification can be downloaded at DC-3 AIRWAYS PANEL MODIFICATIONS.

Adding the GPS to both sides of the panel eliminates the need to be constantly switching panels to monitor both VORs, as intersection changes can be easily navigated on the GPS. Also, if you find that your destination is below minimums, you will no longer have to unrealistically "pause" FS while you dig out or print the instrument approach and landing plates to an airport that is still above IFR minimums. Instead, you simply select and fly the needed approach and landing procedure displayed on the GPS from the left seat. Note: You must use the new GPS icon on top of the icon stack, as the original CP GPS icon will be inoperative.

This modification is not a game mode than can be used instead of learning how to precisely hand-fly the aircraft in IFR weather. Before you can engage the Bendix King "NAV" switch, you must manually fly and trim the aircraft onto the proper flight path and center the VOR needle(s) before engaging the autopilot.

The R4D/DC-3 has no heading indicator or HSI instrument to set the Bendix King "HDG" control. The right-mounted "NAV-GPS" switch selects which receiver the Bendix King autopilot "NAV" switch will use. When you are doing your "Before Takeoff" checklist, be sure to add adjusting the three Sperry autopilot sensitivity controls to zero, as any sensitivity will cause the Sperry to override the Bendix King autopilot.

1. Go to the FS-9 or FS-2002 program folder and open the "Aircraft" folder. To modify the R4D-6, open the "MAAM-SIM R4D-6" folder, and to modify the DC-3, open the "MAAM-SIM DC-3 Passenger" folder.

2. Open the "Panel" folder and make a backup of the panel.cfg file by renaming it "panel_cfg_backup.txt. Then, open this file with a text editor (such as Notepad) and "save as" panel.cfg.

3. Go to Pilot Panel [Window00], and paste the following three lines after the gauge19= line:

gauge20=Beech_Baron!NAV GPS Switch, 219, 330,25,55
gauge21=Bendix_King_Radio!Bendix-King Radio AP, 0, 330,220,68
gauge22=SimIcons!GPS Icon, 48, 630, 17,18

4. Go to First Officer Panel [Window02], and paste the following after the gauge19= line:

gauge20=SimIcons!GPS Icon, 1000, 612,17,18

5. Go to GPS [Window08] and change the "ident=8" parameter by pasting the following:


6. In the "Before Takeoff" section of your checklist, after the "Autopilot - OFF" line, add "Sperry Autopilot Sensitivities – SET TO 0, 0, 0." If these three sensitivities are not set to zero, the Sperry autopilot will override the Bendix King autopilot, and you will not be able to manually override whatever the Sperry autopilot commands until the autopilot is turned off. Note: The Sperry autopilot sensitivity settings can not be saved. They must be reset for each flight.