GP ARMED NOT CAPTURED

[craig.roser]

UMATILLA X23. RNAV GPS A. Garmin G3X GNX375 GMC507. Loaded and activated the approach. Autopilot in APR mode. Lateral guidance perfect from IAF OTIZY back to hold at TENUY after MISSED APPROACH. The autopilot armed GP mode but remained on ALT mode. Why didn't the autopilot follow the GP?

What the best practice for this approach CIRCLING to land?

 

[Bavafa]

Did you intercept the GP? If you are below the glide path when you arm the approach, it will not capture it.

 

[Amadeus]

Did you intercept the GP? If you are below the glide path when you arm the approach, it will not capture it.

Aren't you always below the glide path before you fly level into it to intercept it?

 

[Longez]

Craig,

That is an LNAV approach. No vertical (glidepath) guidance available to capture.

Steve

 

[craig.roser]

Craig,

That is an LNAV approach. No vertical (glidepath) guidance available to capture.

Steve

What is frustrating then, why does the autopilot arm GP! The indication should simply remain ALT.

 

[mburch]

What is frustrating then, why does the autopilot arm GP! The indication should simply remain ALT.

Pages 345-346 in the current G3X Touch pilot's guide (revision Y) cover this; when you press "APR" button on the GMC you are asking the flight director to arm both lateral and vertical moves for an approach.

For information about approaches without vertical guidance, refer to pages 357-359. For LNAV-only approaches you simply use the flight director's GPS mode ("NAV" button on the GMC) and manage the altitude using whatever relevant flight director mode you choose.