Autothrust

[Stevens]

I cannot get Autothrust to work. I got rid of the FAIL message on the ATS window, but I cannot activate ATS whatsoever.

I push it on Ground or in Flight with VNAV enabled, but whatever I try, Autothrust will not come on, ATS pushbutton is not lit.

Can anybody explain to me, what the condotions exactly have to be to get ATS working?

I am sure I forget something to activate, but I don't know what it is.

Help is much appreciated!

Thanks!

[Graeme_77]

Conceptually the ATS is quite different from a 737 type of autothrottle. Let me try and explain it simply:

The ATS will only work if there is a valid thrust rating. Click the PERF button on the CDU, and make sure it shows <ACT> next to a rating.

You can use the TOGA buttons at any point, even  on stand with the engines shut down, to arm the flight directors and ARM the autothrust system. It will then show "N1 TO" on the ATS matrix display. If the flight directors are already showing, you must turn them off and then press TOGA to arm the ATS.

For takeoff, just push the power levers forward or press the "ATS" button on the FCP. This will then engage the ATS to give you takeoff thrust.

If at any point you have FAIL on the matrix display, you must use the ATS Disconnect, (look for at_disc in the bindings) to clear the matrix display before reengaging the ATS.

Hope that makes enough sense to get you going.

[Stevens]

When I push the TOGA switch, the FD appear on the PFD, but the ATS Matrix window stays blank. 
When I push the ATS knob, nothing happens either. 

[J@nek]

Same problem here, in flight FAIL message, I pull the CB (G7) in and out and push ATS again and FAIL message is back. 

But at_disc in the bindings brings ATS back to life.

 

Cheers

Edited January 9, 2022 by J@nek

[Stevens]

I know how to get rid of the FAIL msg. Autothrust disconnect is binded. 
 

But still I cannot switch ATS on. 
 

I have ACT on the perf page see image. 

[Stevens]

I followed the checklist and came to the After Start Checklist point ATS….N1 TO. 
 

I don’t have it as you see in the image. 
 

on the top right the checklist says 1 Action. Can I do something there to make the F/O does the correct switch. 
obviously something is missing here. 

[Rodeo]

The tooltip asks you to make sure the ATS display shows something. First step would be to look at the ATS display

Just this once, I'll try not to be too unhelpful: the ATS display is to the left of the autopilot controls and left of the captain's master caution/warning indicator, above the primary flight display.

Edited January 10, 2022 by Rodeo

[Stevens]

Thanks Rodeo, but I in fact know where the ATS window is. 
 

Maybe you or hopefully the developers could explain the system behavior in the following video. 
I cannot believe this is normal…

[Graeme_77]

You’re asking for takeoff power, cowl anti ice, while running the packs on the engines. IIRC this is not allowed. The procedures show takeoff and landing with the APU running and supplying the packs. There are options for cowl, or 10th stage, but not both.

Also TOGA will not rearm ATS when the flight directors are displayed. You need to remove the flight directors, then press TOGA. This is a real quirk of the Challenger.

Edited January 13, 2022 by Graeme_77
Clarity

[skiselkov]

5 hours ago, Stevens said:

Thanks Rodeo, but I in fact know where the ATS window is. 
 

Maybe you or hopefully the developers could explain the system behavior in the following video. 
I cannot believe this is normal…

This is indeed normal. The reason is quite simple: the ATS needs an N1 limit target to operate. Otherwise, it would have no idea what the maximum allowable thrust is. This value is supplied by the FMC. The FMC uses performance tables made by the aircraft manufacturer to determine what the takeoff thrust limit is supposed to be and if I show what the table looks like, you'll immediately see the source of the problem:

Your SAT is +35 C. At that temperature, the FMC has no data to compute a takeoff N1 target, so the target blanks and the ATS goes to FAIL (and cannot be re-engaged). Take the cowl A/I off, FMC goes back to the normal takeoff tables and voila, ATS is back in business.

Edited January 13, 2022 by skiselkov

[mraviator]

Just adding that I also cannot get ATS to engage. It worked great for many flights and stopped working a week or so before the 1.1 update. 

[Bernardo_Gui]

no more ATS for me, 

 

it used to work great for a few first flights; then never went back online again. it happened inflight during approach; then after i have landed and used the same airframe the next day, never could i engage the ATS again.   when i press ATS it shows "FMC ERR" on the matrix. i don't get the "FAILED" message anymore at all.  i did my last fly on full manual throttle, this time after landing i have cleared up all the flp / perf  and fuel data from the FMS before leaving the aircraft and saving the airframe before tomorrow. if the ATS will not work on my next flight; then i don't know .. 

this is very frustrating and must be cleared out, someone please do a video tutorial explaining all the proper ATS conditions. thanks advance. 

Edited January 26, 2022 by Bernardo_Gui

[ois650]

Hello Bernado, 

I recommend doing a full power down of the aircraft and upon restart cycle the FMC (IDX -> STS -> Cycle Nav Databases). This should clear out any errors that are originating in the FMC. 

If this does not work I recommend ensuring that there are no failures triggered. 

Let us know how you get on. 

Best regards,

[Bernardo_Gui]

17 hours ago, oisin650 said:

Hello Bernado, 

I recommend doing a full power down of the aircraft and upon restart cycle the FMC (IDX -> STS -> Cycle Nav Databases). This should clear out any errors that are originating in the FMC. 

If this does not work I recommend ensuring that there are no failures triggered. 

Let us know how you get on. 

Best regards,

i did it all, i have cleared the previous flp and reset everything i could. it seems to have worked and now i have ATS working back on track as before, except "DISENG'D" messages i have at crz 

[ois650]

Make sure you select CLB power before passing 15000ft, otherwise ATS will lose N1 target and disengage. This may be the issue?

[honeycool75]

On 1/28/2022 at 2:54 AM, ois650 said:

Make sure you select CLB power before passing 15000ft, otherwise ATS will lose N1 target and disengage. This may be the issue?

What is "CLB power"?

[rjb4000]

2 hours ago, honeycool75 said:

What is "CLB power"?