ATS Questions

[alstr]

Hi, I have a variety of noob questions relating to ATS I was hoping someone could shed some light on to help me further understand this wonderful aircraft.

1. I've encountered a few scenarios, usually on approach, where ATS fails and I can't reconnect it. I want to better understand the reasons for this. I'm assuming it's because the aircraft can no longer maintain the speed selected, or because of some manual intervention. How can I rectify it?

2. I also want to clarify the colour of the speed on the PFD. Is this correct; Pink - ATS active and following speed in VNAV setup; Blue with ATS illuminated - speed set at number dialled in by speed knob; Blue with ATS not illuminated - ATS disengaged, power set by throttle position. Sometimes I'm not sure whether ATS is active or not.

3. What is the meaning of the throttle sliders that appear in the bottom right hand corner of the screen, indicating that they should be moved to the position shown?

4. Sometimes when climbing out with a heavy fuel load the speed plateaus at around 200kts and then starts to fall backwards. ATS fails here also as the aircraft appears to be climbing too steeply to meet the speed asked of it (presumably partly answering my first question). I usually set speed to 231 before takeoff then after the packs transition engage VNAV climb at 250 kts. What is the best procedure here?

(I am sure the real world detail is much more complex than can be distilled here but a general overview is helpful).

Thanks.

Edited March 31 by alstr

[Prefect99]

On 3/31/2026 at 11:28 AM, alstr said:

1. I've encountered a few scenarios, usually on approach, where ATS fails and I can't reconnect it. I want to better understand the reasons for this. I'm assuming it's because the aircraft can no longer maintain the speed selected, or because of some manual intervention. How can I rectify it?

Are you following the built in checklist and using the auto-FO? This is either not setting a thrust reference or an incorrect bleed transition/setting.

On 3/31/2026 at 11:28 AM, alstr said:

2. I also want to clarify the colour of the speed on the PFD. Is this correct; Pink - ATS active and following speed in VNAV setup; Blue with ATS illuminated - speed set at number dialled in by speed knob; Blue with ATS not illuminated - ATS disengaged, power set by throttle position. Sometimes I'm not sure whether ATS is active or not.

It should be clear when ATS is engaged as there is the mode status display in front of you tells you what it is doing. Green top row for modes and yellow bottom for cautions and disengagement. It is a basic autothrottle and more of a bolt on. It can essentially only do N1 and Speed.

The PFD speed bug is either cyan when the FCP knob has set the speed (i.e. you) or magenta when the FMS is controlling it.

On 3/31/2026 at 11:28 AM, alstr said:

3. What is the meaning of the throttle sliders that appear in the bottom right hand corner of the screen, indicating that they should be moved to the position shown?

Your hardware throttles do not match the position of the in sim throttles. Move your throttle to 'catch' the in sim throttles.

On 3/31/2026 at 11:28 AM, alstr said:

4. Sometimes when climbing out with a heavy fuel load the speed plateaus at around 200kts and then starts to fall backwards. ATS fails here also as the aircraft appears to be climbing too steeply to meet the speed asked of it (presumably partly answering my first question). I usually set speed to 231 before takeoff then after the packs transition engage VNAV climb at 250 kts. What is the best procedure here?

What vertical mode are you climbing in? The usual departure method is to bug 200 kts, complete the after take off checks (flap up being key) then accelerate to 250 kts. The climb schedule is either 250/250/0.72 or 250/300/0.78 for <10k alt/>10k alt/mach changeover. It's listed in the documents included in the aircraft folder.

For a foolproof but steep climb use FLC and you won't stall.

[alstr]

I appreciate the time taken to answer. I've got a slightly better grasp of it now and will use your notes to refine further. Thanks again.