I've noticed that turning on the TBM 850 autopilot does not also automatically turn on the FD -- you have to manually turn on the FD. Even if you turn on the AP, and then turn on an AP mode such as HDG or NAV, the FD does not automatically turn on. This seems unusual to me.

However, if the AP is off and you turn on an AP mode, such as HDG or NAV, the FD does turn on automatically, I suppose to provide you the necessary guidance since you, and not the AP, are flying the plane.

Is this how you are seeing the FD works?

Al

Edited November 22, 20232 yr by ark

40 minutes ago, ark said:

Even if you turn on the AP, and then turn on an AP mode such as HDG or NAV, the FD does not automatically turn on. This seems unusual to me.

That does not sound right..

 

2 hours ago, Bert Pieke said:

That does not sound right..

I agree, which is why I have raised the issue. On the other hand, it is somewhat of a unique AP,  e.g., with the separate gauge for the AP vertical speed mode. If other BS TDM 850 users are not seeing the same thing, I will investigate further. Maybe I have some type of weird conflict going on.

Al

Edited November 22, 20232 yr by ark

Hmm... found this AP info in the Bendix/King KFC 325 Digital Flight Control System Pilot's Guide on pages 2.4/2.5:

 

Al

 

Edited November 22, 20232 yr by ark

1 hour ago, ark said:

If other BS TDM 850 users are not seeing the same thing, I will investigate further. Maybe I have some type of weird conflict going on.

I just tried it... it seems inconsistent.. If I hit AP, and then HDG, FD mode comes on.  If I hit HDG and then AP, no FD..  Seems hit and miss to me..

Edit, may actually be reversed.. 😉

Edited November 22, 20232 yr by Bert Pieke

18 minutes ago, ark said:

Hmm... found this AP info in the Bendix/King KFC 325 Digital Flight Control System Pilot's Guide

This guide says that pressing HDG will also engage FD..  That does not happen consistently in this airplane..

I would call that a bug. 😎

Edited November 22, 20232 yr by Bert Pieke

18 minutes ago, Bert Pieke said:

This guide says that pressing HDG will also engage FD..  That does not happen consistently in this airplane..

I would call that a bug. 😎

I should clarify here: When I push one of the AP buttons, I do see the expected text annunciation ( e.g., HDG, FLC, etc) show up on the top of the Attitude Indicator display.  What I don't see if I have first turned on the AP is the green "wings" appear on the AI display unless I press the FD button.

Regardless, there does seem to be some kind of bug. Unlike you, if I turn on the AP and push heading I don't see the green wings show up on the AI although the yoke does seem to respond as if trying to turn the plane to the desired heading.

Thanks Bert for looking into this a bit.

Al

Edited November 22, 20232 yr by ark

Duplicate post, please delete.

Edited November 22, 20232 yr by ark

49 minutes ago, ark said:

Unlike you, if I turn on the AP and push heading I don't see the green wings show up on the AI

Not sure it is consistent, or if it depends on some prior action..

The logic is screwed up.. If I push AP and then HDG, no FD.

Either one of these buttons should also turn on the FD. 

Then push AP, and the autopilot turns off and FD turns on.. 😉

Edited November 22, 20232 yr by Bert Pieke

Temporary fix here:  https://community.justflight.com/topic/5656/ap-logic-inconsistent/2

Related to the above, I've noticed the following which I think is another autopilot bug (with or without the temporary fix above in place):

If just the AP and FD are on, the displayed modes are ROL and PIT, which is fine. However, if you then turn off the AP so only the FD is on, only the ROL mode is displayed, there is no vertical mode displayed. Seems to me if the AP or FD is on, there should always be both a lateral and vertical mode displayed. Interestingly, if you just turn on the FD, you again get both the ROL and PIT modes displayed. The bug also shows up in other AP mode combinations, for example, if HDG and ALT are on with the FD and AP on, and you turn off just the AP, the vertical mode again disappears.

I'd like to know if others are also seeing this AP behavior.

Thx,

Al

Edited November 30, 20232 yr by ark

3 hours ago, ark said:

However, if you then turn off the AP so only the FD is on, only the ROL mode is displayed

I see this as well... interestingly, if you turn off AP via the red yoke button, PIT stays on.

The code for the two events seems similar, so why?   Hopefully, the author cleans this up, now that he has been alerted to the AP problem.

Think I found it... check the JustFlight forum: https://community.justflight.com/topic/5656/ap-logic-inconsistent/2

 

Edited November 30, 20232 yr by Bert Pieke