Piper CHEROKEE CRUISER PA-28-140, Information Manual, Page: 204 / 212

AFMS, Garmin G5 AML STC 190-01112-13 Rev. 5
Page 4
–
2
Autopilot Operations with the G5 HSI
The G5 and optional GAD 29B offer various integration capabilities dependent upon the type of autopilot installed
in a particular aircraft.
The G5 Electronic Flight Instrument installation in this aircraft provides the following autopilot functions
(appropriate boxes will be checked):

This installation does not interface with the autopilot (basic wing leveling autopilot or no autopilot is
installed in the aircraft).

A GAD 29B Adapter is installed in this aircraft.

Course / NAV Selection coupling to the autopilot.

Heading Bug coupling capability to the autopilot.

Roll Steering (GPSS) emulated via heading mode.
OR

Roll Steering capable autopilot (GPSS menu function for emulation not applicable).
Course / NAV Selection Coupling to the Autopilot (If Configured)
When operating the autopilot in NAV mode, the deviation information from the installed navigation sources (i.e.
GPS or NAV) is switched via the navigation source. The NAV source displayed on the HSI is the NAV source
the autopilot is following. Many autopilots also use the course datum to determine the best intercept angles
when operating in NAV mode.
Heading Bug Coupling Capability to the Autopilot (If Configured)
When operating the autopilot in HDG mode, the difference between the HDG bug location on the HSI and the
actual aircraft heading creates an error signal which the autopilot will minimize by turning in the direction of the
bug. If the bug is turned more than 180 degrees, the autopilot may turn the airplane in the opposite direction of
the desired turn.
Roll Steering (GPSS) Emulated via HDG Mode (If Configured)
For autopilots that do not support digital GPSS signals, GPSS functionality may be emulated by operating the
autopilot in HDG mode and selecting GPSS from the G5 menu. If the autopilot is already designed to receive roll
steering information, the data is transmitted digitally from the navigator to the autopilot.
When GPSS is selected on the G5 menu, the heading bug on the HSI changes to a hollow outline and a crossed-
out heading bug appears on the G5 HSI display indicating that the autopilot is not coupled to the heading bug.
The bug is still controllable and may still be used for reference.
When GPSS is selected on the G5, GPSS turn commands are converted into a heading error signal to the
autopilot. When the autopilot is operated in HDG mode, the autopilot will fly the turn commands from the GPS