Autothrottle engages during taxi...question

[gpb500]

Why would the autothrottle engage (i.e., go active) in a situation where I have the throttle levers pulled back, getting ready to taxi (engines idling), arm A/T and it goes nuts like I'm taking off but have not yet hit the to/ga button.  Everything looks right unless it's an odd hardware mapping problem.  Only happened once so far (1.0.4) but a mystery.

Thanks.

[FloB]

You'll have to post a screenshot that shows the whole cockpit setup. All I know is that you shouldn't arm A/T until lined up on the RWY. That's what the pilot says .

 

 

[mmerelles]

you definitively pressed TOGA or N1 or SPD mode, maybe you were rotating views on the cockpit and made an unexpected clic on any of those 3, or you have key/button mapping you are unaware off got them pressed.

[gpb500]

No, I didn't press any buttons by accident.  It happened 3 times in a row.  I kept disabling it, then flip the switch and it would immediately go to full power.  I specifically mapped a TO/GA button and had not pressed it...difficult to do by accident.  Maybe it's that XPUIPC thing or something.

As for arming it just before departure, this pilot arms it before engine start which I thought was odd, but that's how they do it real world.  I didn't do that, I armed it when I was ready to taxi.  You can see it already armed right as they start engine 2 (very beginning of video), you'd have to look at the end of Part 2 to see when it was switched on.  A good set of videos if you haven't seen them.  Thanks.

 

[WR269]

Did you press VNAV by any chance??? I have seen this happen when people press VNAV while on the ground

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[gpb500]

No, didn't enable VNAV/LNAV (and then A/P) until well above 500 ft.  But good thought...thanks.  I'm starting to think it's a fluke...if it happens again I'll update here but so annoying after a lengthy setup.

[gpb500]

OK, checking flight controls...test speed brakes mapped to standard XP speed brakes (dial on throttle), engages N1 if A/T armed.  Once I test the speed brakes, I can no longer arm A/T without it going into N1.  I haven't even started to taxi yet.  Can someone test this?  Thanks!

EDIT: Will post under bugs.

Edited May 27, 2016 by gpb500

[Iain]

Did you post this in bugs?

I can reproduce a very similar problem.  If I press VNAV on the ground, then arm the AT, the throttle rise to takeoff thrust.  They stay there even if I disarm the AT.   Eventually they go back to idle and some sort of click combo and movement of the throttles although it is not clear.

Question for me is, I know I should not press the VNAV on the ground, but if I do with AT armed, should the throttles rise?  Surely for takeoff, the TOGA has to be pressed.

Edited June 13, 2016 by Pinky Ponk

[Litjan]

1 hour ago, Pinky Ponk said:

Did you post this in bugs?

I can reproduce a very similar problem.  If I press VNAV on the ground, then arm the AT, the throttle rise to takeoff thrust.  They stay there even if I disarm the AT.   Eventually they go back to idle and some sort of click combo and movement of the throttles although it is not clear.

Question for me is, I know I should not press the VNAV on the ground, but if I do with AT armed, should the throttles rise?  Surely for takeoff, the TOGA has to be pressed.

No.

This is no NG. Don´t press anything on the ground, except for TOGA when you want to take off. The autothrottle will happily go to full thrust for a number of modes, VNAV being one of them. THis is also the reason that the procedures are VERY specific about not arming it until you line up on the runway.

Happy flying, Jan

 

[Rodeo]

4 hours ago, Pinky Ponk said:

They stay there even if I disarm the AT.   Eventually they go back to idle and some sort of click combo and movement of the throttles although it is not clear.

A/T will advance the throttle to full forward, when you disconnect it, your thrust lever and the in-sim levers will be out of sync. You need to advance your lever to full forward until they match in in-sim levers (there's a visual aid in the lower-right portion of the screen), and then you'll regain manual thrust control.

[Iain]

Got it!

I am finding out the differences with the NG (you know from who) and this.  I was suspecting a full deflection of the throttle was what I done to get the throttle under control.  I won't activate it on the ground again

I am really lucky in that I gave XP10 another go, I skipped the demo and bought it last week, stumbled across this ac (intending to buy it only to try the DC6) and I am in love with it.  Simming since Tornado from Digital Integration in 1993 I have 1000's hours simming, and 100's of hrs on the PMDG 737.

The ac is missing a few features, non that are very important to me, and non that take away enjoyment.  The one thing I have found is this ac has an abundance of character, something that is not easy to program into a sim I guess, but it is just a joy to fly.  Great sounds, great fun to hand fly, you feel the mass of the ac when flying, there is real inertia there.   The little things like the dimming of light of the overheard when switches are flicked...amazing, the strip light under the MCP that flickers when it comes on, perfection!

Millions to learn with XP10 but will only get better.

Keep up the good work.

[frumpy]

19 minutes ago, Pinky Ponk said:

Simming since Tornado from Digital Integration in 1993 I have 1000's hours simming, and 100's of hrs on the PMDG 737.

 

Yeah! 550 kts @ 200ft, hoping to evade them SAMs and trying to fly a straight line over that enemy runway...

 

[Litjan]

33 minutes ago, Pinky Ponk said:

Got it!

I am finding out the differences with the NG (you know from who) and this.  I was suspecting a full deflection of the throttle was what I done to get the throttle under control.  I won't activate it on the ground again

I am really lucky in that I gave XP10 another go, I skipped the demo and bought it last week, stumbled across this ac (intending to buy it only to try the DC6) and I am in love with it.  Simming since Tornado from Digital Integration in 1993 I have 1000's hours simming, and 100's of hrs on the PMDG 737.

The ac is missing a few features, non that are very important to me, and non that take away enjoyment.  The one thing I have found is this ac has an abundance of character, something that is not easy to program into a sim I guess, but it is just a joy to fly.  Great sounds, great fun to hand fly, you feel the mass of the ac when flying, there is real inertia there.   The little things like the dimming of light of the overheard when switches are flicked...amazing, the strip light under the MCP that flickers when it comes on, perfection!

Millions to learn with XP10 but will only get better.

Keep up the good work.

Hi and thanks for the kind words! We have a thread here:

http://forums.x-pilot.com/forums/topic/8526-things-that-are-not-going-to-be-in-v10/

that is attempting to warn people of the things we are still missing. I am going to update this thread with every patch until it is all stricken out .

I also flew DI´s Tornado (including Desert Storm) and about every FlightSimulator out there since the mid-80s (remember MicroProse? Jane´s? F-16 Combat Pilot?). The secret with Tornado was to manually fly below 100´ - no SAMs would ever launch!

Happy flying, Jan

 

[Tom Stian]

4 hours ago, Litjan said:

No.

This is no NG. Don´t press anything on the ground, except for TOGA when you want to take off. The autothrottle will happily go to full thrust for a number of modes, VNAV being one of them. THis is also the reason that the procedures are VERY specific about not arming it until you line up on the runway.

Happy flying, Jan

 

I also follow that procedure with not enabling A/T before lined up on the runway. But it looks like some companies already engage it before startup, when ready for taxi  or while taxing. Bad habits?

 

 

[Litjan]

Can´t really say anything about how these guys do it - except that I wouldn´t do it . It IS possible that they are running a higher FMS standard that will not allow A/T activation on the ground, I simply don´t know.

Jan

 

[Tom Stian]

2 hours ago, Litjan said:

Can´t really say anything about how these guys do it - except that I wouldn´t do it . It IS possible that they are running a higher FMS standard that will not allow A/T activation on the ground, I simply don´t know.

Jan

 

Tried to do some research around this, its a interesting subject.
I understand that you cant point out what other companies are doing. And maybe there is some variation around this as you mention. Would be fun to see a checklist from a company that are arming A/T in a earlier phase.

But when reading the Boeing manual and one from a other company, it clearly says that arm the autothrottle when cleared for takeoff and approaching/entering the runway.

So we all should listen to you Jan 

checklist 1:

 

checklist 2:

Edited June 13, 2016 by Tom Stian

[frumpy]

15 hours ago, Litjan said:

The secret with Tornado was to manually fly below 100´ - no SAMs would ever launch!

 

I've never heard about flying below 100ft to evade SAMs, never tried that... ...uh well, I think I did once and hit a powerline

(Thinking about it, there is a Pentium 90 with a live installation still up in the attic...hmm!)

[Rodeo]

21 hours ago, Litjan said:

Can´t really say anything about how these guys do it - except that I wouldn´t do it . It IS possible that they are running a higher FMS standard that will not allow A/T activation on the ground, I simply don´t know.

Maybe they're just daredevil pilots…

[gpb500]

Just noticed a bunch of replies here.  In the end, this may have been caused by XPUIPC.  After removing it, I no longer could reproduce the problem.  It's interesting how different pilots engage it at different times while the boeing manual is specific.  Thx all.

[Iain]

Quick question.  Scenario is to engage AT on entering runway, throttles to 40%, everything stable, TOGO, throttles move to TO power, then decide to do a rejected takeoff.  AT off, rock the throttle full forward to idle and manual control back.

Taxi back to runway, now I engage AT and the power always wants to go to TOGA?  How do I cancel the first TOGO and allow me to press it again?

Similar thing happened to me when landing at EGPF, approach was not stable, TOGO and went around from 500ft.  Flew the missed approach with AT engaged, during next ILS approach, switched AT off at 500ft for a full manual landing, but throttles were not manual, they were stuck at 55%.  Rocked the throttle, no luck, could never get manual control back no matter what.  Landed at 170kts, got reverse on, but went off the end of RW05 and ended up bobbing up and down in the river Clyde! (quite realistic btw, but not the plan).  Bugs or pilot error?

 

Just completed a flight from KRDM to KOTH, as long as I never hit TOGO and the initial press, I am not having any issue. Was a great flight tonight, really loving the character of this ac and X-plane in general over FSX.

[Tchou]

1 hour ago, Pinky Ponk said:

Quick question.  Scenario is to engage AT on entering runway, throttles to 40%, everything stable, TOGO, throttles move to TO power, then decide to do a rejected takeoff.  AT off, rock the throttle full forward to idle and manual control back.

 

At least this part is pilot error : 

engage AT when entering the runway

40% N1 everything stable 

engage TOGA an Push your hotas throttle to full 

to reject take off, just pull throttle to idle. 

[Litjan]

Hi and thanks for the report,

in addition to Tchou´s advice for avoiding this problem, I suspect a jittery hardware throttle triggering the Rejected Takeoff Mode (we are basically just watching if the hardware throttle is "moving" and "being at idle").

To get out of the T/O mode, make sure that you turn off the A/T (switch) and also turn off both FD´s.

To regain manual control of the thrust-levers during approach, make sure that the "ghost-throttles" match up with the hardware throttles long enough - i.e. don´t yank back and forth, but move over slow and deliberately. There is a tiny time-delay to avoid jittery throttles to display the ghost throttles all the time.

Let me know if this helps?

Jan

 

[Iain]

Hi

Thanks for the advice.  Reason I didn't pull throttles back for a RTO was because it was very low speed RTO so there was no panic, granted it is the wrong procedure.  I will take note of the FD's as well, I left them on the whole time.

For regaining manual control, I will try the trick with matching the ghost throttles for long enough, good chance I am not doing that.

 

Happy flying.