How to - Autopilot Operation

[richboy2307]

The YS-11 is equipped with the Brittain B-5C, three-axis Automatic Flight Control System—a robust, low-power autopilot designed to enhance stability and reduce pilot workload across roll, pitch, and yaw axes. The B-5C integrates seamlessly with the aircraft’s navigation system to provide smooth course tracking and altitude hold. Its simplicity, reliability, and minimal electrical draw make it especially well-suited for regional turboprops like the NAMC YS-11, where operational efficiency and mechanical resilience are paramount.

 

Autopilot Control Panel

 

 

1) Autopilot Disengage
2) Heading Hold
3) NAV Hold
4) Localizer and Glideslope Hold (APPR Mode)
5) Turn Knob
6) Vertical Speed Selector
6) Altitude Hold 

Engaging the Autopilot

The B-5C autopilot system lacks a dedicated master switch for activation. Instead, engagement occurs through the selection of a lateral mode—such as Heading Hold, Nav Hold, or Localizer Hold. Activating any of these modes automatically engages the Vertical Speed mode, maintaining the aircraft’s vertical speed at the moment of engagement.

An alternative method of engaging the autopilot is through the Altitude Hold function. However, this activates only the altitude control—lateral guidance must be selected separately via Heading Hold, Nav Hold, or Approach Hold to achieve full autopilot functionality.

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Note: This autopilot is not fitted with an altitude preselector. The pilot must gradually reduce the vertical speed as the desired altitude is reached and engage the Altitude Hold mode to level off.

 

Engaging Heading Hold

	Select the desired heading in the Directional Gyro using the Heading Knob. The knob can also be pushed to synchronize the bug to the current heading. Press HDG in the Autopilot Control Panel. Note: this will engage the Vertical Speed mode as well and maintain the vertical speed present at the moment of engaging Heading Hold.
Engaging Altitude Hold

Press ALT, this will command an immediate level off at the current altitude. Note: if the autopilot was not previously engaged only the ALT mode will engage. A lateral mode must be subsequently engaged if desired.

Commencing a Climb/Descend 

	Disengage the Altitude Hold mode if it was previously engaged.
	Turn the Vertical Speed Selector to select the desired vertical speed target.   The target will be displayed as a tooltip and can be seen by placing your cursor over the selector.

Using the Turn Knob

	If the autopilot was not previously engaged, engage it by first selecting Heading Hold.
	Turn the knob to the left or right to initiate a turn in the desired direction. When the desired heading is reached, turn the knob back to the middle (neutral position). Note: The turn will continue as long as the knob is not neutral.

Capturing and Tracking a VOR Radial

	Tune the desired VOR in the NAV/DME radio.   Note: ensure the unit is turned on. This is controlled by the top left switch.
	If using a GPS unit, VLOC must be displayed. If GPS is displayed, press the CDI button to change the guidance to VLOC.
	Select the desired course in the Course Deviation Indicator by using the lower left knob. The course is displayed at the top of the instrument (020 in this case). The top right knob reverses the set course by 180º.
	Press TRK to engage the mode.

Capturing and tracking the GPS Route

	In your desired GPS unit, select GPS. If VLOC is displayed, press the CDI button to change the guidance to GPS.       Press TRK to engage the mode. The autopilot will now follow the GPS guidance.

Executing an ILS Approach 

	Tune the desired ILS in the NAV/DME radio.   Note: ensure the unit is turned on. This is controlled by the top left switch.
	If using a GPS unit, VLOC must be displayed.   If GPS is displayed, press the CDI button to change the guidance to VLOC.
	Select the desired course in the Course Deviation Indicator by using the lower left knob. The course is displayed at the top of the instrument (020 in this case). The top right knob reverses the set course by 180º.
	Press LOC to engage the Approach mode. Note: the real autopilot was capable to only track the Localizer, hence the LOC text in the button. For ease of use it was decided to simulate the Approach mode (Localizer and Glide Slope tracking).   The Glide Slope indication is shown in this image.   The aircraft is on the Glide Slope when the horizontal white line is in the middle of the instrument.