Adjusting the Heading Bug

[Beagle12 139]

With the autopilot used in the HDG mode, when I adjust the Heading Bug, the aircraft will turn and follow the Red Heading indicator, as it should.

However, when I press and turn the knob directly to the left of the HSI, the aircraft ignores any future input of the heading bug.

Why is this ?? And what is the purpose of this "push" knob ??

[ark 1,288]

It would be helpful to know what aircraft you are talking about.

On some nav systems, such as the G1000, pushing in the heading bug knob aligns the heading bug with the current aircraft heading -- is this what you are seeing?

Al

Edited September 13, 2021 by ark

[Beagle12 139]

it is the C172 steam gauge version.

[ark 1,288]

21 minutes ago, Beagle12 said:

it is the C172 steam gauge version.

There is no HSI in the Asobo steam gauge C172. If you are talking about the gauge directly below the AI (Attitude Indicator) that is the DG (Directional Gyro) that indicates the current heading of the aircraft. DGs that are not 'slaved' (to a device called a flux gate) will drift (the heading they indicate will not be accurate)  and have to be periodically reset (adjusted a few degrees to the left or right) as needed during flight. The knob on the lower left of the DG is for adjusting the DG so in level, steady flight it indicates a heading that agrees with the magnetic compass.

Al

Edited September 13, 2021 by ark

[Beagle12 139]

Thanks Ark. That is a very good explanation. Easy to understand.

[Bobsk8 12,582]

1 hour ago, ark said:

There is no HSI in the Asobo steam gauge C172. If you are talking about the gauge directly below the AI (Attitude Indicator) that is the DG (Directional Gyro) that indicates the current heading of the aircraft. DGs that are not 'slaved' (to a device called a flux gate) will drift (the heading they indicate will not be accurate)  and have to be periodically reset (adjusted a few degrees to the left or right) as needed during flight. The knob on the lower left of the DG is for adjusting the DG so in level, steady flight it indicates a heading that agrees with the magnetic compass.

Al

To adjust it quickly just hit the D key.