Engines turn to idle during take-off run

[mato-tmd 0]

Hi Folks, every time i try to lift my new PMDG 737 NGX in the air both engines return to hardware thrust-lever position after 75% of the take-off run (Autothrust still active!).The cockpit is set up as usual, V2 is set from QRH recommendation in FMC.I´m sure it´s my mistake, but i don´t find out which settings are wrong. Who can give me some information?Looking forward to your help... Happy Landings Matth (IVAO Germany)

[badderjet 181]

every time i try to lift my new PMDG 737 NGX in the air both engines return to hardware thrust-lever position after 75% of the take-off run (Autothrust still active!).

Aintcha answering your own question? Well, then place your hardware throttle to takeoff thrust to get rid of this effect... You are aware the THR HOLD has little to do with autothrottle and is a mode that will disconnect A/T servos from the levers, hence whatever you set manually will be your thrust target?

[masneoquil 66]

The problem here are the spikes on the Throttle control. When you reach 80 the AT turn to ARM, and here you can control the Throttles manually. I'm sure that the spikes in the joystick is making the engines go idle.There is an option on the CDU (i don't remember where) that make the simulation to ignore any joystick input once you push TO/GA.

[badderjet 181]

Yeah I think the option is how or when to allow manual override - never, always (which is semi-realistic but not so realistic on HW throttles without servos), and "in THR HOLD and ARM only", which is probably most realistic for most HW throttles. Although I'm not 100% if that option made it into HF4, but before that it was definitely there.

[masneoquil 66]

Yeah I think the option is how or when to allow manual override - never, always (which is semi-realistic but not so realistic on HW throttles without servos), and "in THR HOLD and ARM only", which is probably most realistic for most HW throttles. Although I'm not 100% if that option made it into HF4, but before that it was definitely there.

Yeaph, it is still there.

[mato-tmd 0]

Hi folks, thanks a lot for your quick and detailed answers! The setting "in THR HOLD and ARM only" was chosen but I still don't understand WHY Thrust mode changes from N1 to THR HOLD... Is it because of the different HW throttle setting? Choosing the "Never" option would mean to loose the option of a rejected take off...Will try to get a little bit deeper in system knowledge when time permits! So far Matth

[ACA857 5]

N1 to THR Hold is normal during takeoff. There is a related issue where the throttles are overiding the AT when active when they should not be which I have already reported to PMDG support.

[badderjet 181]

I still don't understand WHY Thrust mode changes from N1 to THR HOLD...

Erhm... cause it's how the system works??? You seriously need to read some FCOM, for a start on your issue Vol II 4.20.6 & 4.20.12 is your friend. THR HLD allows complete manual control due to disconnected servos. It's still good and recommended practice to hit the disco switches whenever aborting for example. Since you could have aborted when N1 was still active, which will still allow manual override (against the servos), but once you get your hands off the levers they would obviously advance again, which you probably wouldn't exactly look for during an RTO. Other than that, once THR HLD is announced you full authority over the levers... (until another mode engages)

[masneoquil 66]

Hi folks, thanks a lot for your quick and detailed answers! The setting "in THR HOLD and ARM only" was chosen but I still don't understand WHY Thrust mode changes from N1 to THR HOLD... Is it because of the different HW throttle setting? Choosing the "Never" option would mean to loose the option of a rejected take off...Will try to get a little bit deeper in system knowledge when time permits! So far Matth

If you can't calibrate your throttle axes you should choose never on that option. Otherwise yo will have the same problem always

[davierosoft 13]

Te issue, that is not an issue, can be solved by disabling throttle movement in thrust hold (from the menus), in this mode the only way to manually move throttles will be disengaging AT.

[mato-tmd 0]

Hi, thanks once more for your helpful comments (badderjet, you MUST be a real-world pilot...); going to simulate the servos of my X52 throttle by hand before thrust mode changes from N1 to THR HOLD since i find a more satisfying solution... Matthias

[Gabster 7]

I have the same problem with the saitek x52. It's always moving a little bit and that interrupts the TO/GA Mode. What helped for me was to leave the throttle at 0 and just push TO/GA. In 0 Position I have no unwanted Hardware movement on the throttle. But somehow some of my approaches end up with a go arround because of full thrust...Gabriel

[jbassue 181]

Erhm... cause it's how the system works??? You seriously need to read some FCOM, for a start on your issue Vol II 4.20.6 & 4.20.12 is your friend. THR HLD allows complete manual control due to disconnected servos. It's still good and recommended practice to hit the disco switches whenever aborting for example. Since you could have aborted when N1 was still active, which will still allow manual override (against the servos), but once you get your hands off the levers they would obviously advance again, which you probably wouldn't exactly look for during an RTO. Other than that, once THR HLD is announced you full authority over the levers... (until another mode engages)

Etienne, you appear to be sounding quite a bit harsh and aggressive these days? :|That's not like you.

[badderjet 181]

Sorry man, didn't mean to come across rude or anything. Always too easy to get a message across the wrong way by text-exclusive communication I guess... I'm willing to help people out where I can! Hope he didn't take my pointer to the FCOM sections in the wrong way. They basically describe the AFDS mode scenarios during takeoff, which is probably something useful for him.

[jbassue 181]

Sorry man, didn't mean to come across rude or anything. Always too easy to get a message across the wrong way by text-exclusive communication I guess... I'm willing to help people out where I can! Hope he didn't take my pointer to the FCOM sections in the wrong way. They basically describe the AFDS mode scenarios during takeoff, which is probably something useful for him.

I know what you mean, it's no problem, as long as you are helping (: