Bug - 737-800. Reverse thrust, push F1 and reverse goes into forward

[compdiff]

Cant his bug be fixed?

Using keyboard to go into reverse thrust to push out (F2) and then when you want to cut thrust (F1) the velocity you were travelling in reverse, suddenly moves forward.

If travelling say 5 knots in reverse and hit F1, instantly changes to forward 5 knot.

Help!

[Captain Kevin]

First, PMDG requires you to sign your posts with your first and last name, which you agreed to when you created an account here. Failure to do so can result in posts being removed without warning, which would make it difficult for us to help you if that happens. You can set up a signature to avoid forgetting by following the instructions here:

https://forum.pmdg.com/forum/main-forum/general-discussion-news-and-announcements/3201-signature-banners-signature-instructions-and-other-pmdg-forum-resources-updated-25feb19

If you're in full reverse thrust and you hit F1, you've stowed the thrust reversers at a high N1, but you haven't given the engines time to power down before stowing the reversers. If you still have a high N1, the engines are going to produce forward thrust. Normally, what would happen is around 80 knots, you would go from full reverse to idle reverse, so you would be at idle N1, and then at 60 knots, you would stow the reversers.

[[email protected]]

Why do you make your Full Name so hard to read?

[Captain Kevin]

If you really must know, I heavily despise my last name for reasons I'm not going to go into on this forum.

[Emi]

Cant his bug be fixed?

Using keyboard to go into reverse thrust to push out (F2) and then when you want to cut thrust (F1) the velocity you were travelling in reverse, suddenly moves forward.

If travelling say 5 knots in reverse and hit F1, instantly changes to forward 5 knot.

Help!

It's not a bug, you're mishandling the plane. What would you expect to happen when you have your engines at 80% N1 and you stow those revesers immediately? Of course it takes time for the engine to reduce to IDLE thrust and in the meantime you get positive thrust out of it.
Return to reverse IDLE, when stabilized there take them out of reverse.
And to be sure you're using the right technique, at around 60kt the latest you should reduce your thrust to reverse IDLE, then keep that until stopping is 100% assured to avoid the engines going into ground IDLE from where it takes almost 10 seconds longer to return them to full reverse if needed.

[sebihepp]

May I ask how I can go into reverse idle? Well, I know what to do with the thrust levers in the real airplane, but the ones I have at home don't have an axis for reverse - I just have a button. How do you get into Reverse Idle quick and reliable?

[jrw4]

For me, the easiest thing was to associate a throttle or joystick button with the HOLD THROTTLE REVERSE THRUST option. You can find that option under Power Management/Throttle in the Controls Options menu of MSFS.. Operation is simple: immediately upon landing while the thrust lever is in the idle position, press the associated button. This will deploy the thrust reversers. Advance the thrust levers as required to assist deceleration, then pull the levers back to idle while continuing to hold the button. When stopping is assured, you can release the button to stow the reversers.

No function keys required. No abrupt change in thrust. Easy peasy.

[bobsk8]

First, PMDG requires you to sign your posts with your first and last name, which you agreed to when you created an account here. Failure to do so can result in posts being removed without warning, which would make it difficult for us to help you if that happens. You can set up a signature to avoid forgetting by following the instructions here:

https://forum.pmdg.com/forum/main-forum/general-discussion-news-and-announcements/3201-signature-banners-signature-instructions-and-other-pmdg-forum-resources-updated-25feb19

.

Says the person who hides his name in an unreadable font.....😉

[HighFlier]

It is possible to go from full reverse to reverse idle without using a “hold reverse” key command. However, you will need a program like FSUIPC to do so. I managed to successfully map the full reverse and idle reverse “detents” on my TCA Quadrant to full reverse and idle reverse in the PMDG737. The way I did it though only only allows me full reverse or idle reverse, nothing in between.

[bobsk8]

It is possible to go from full reverse to reverse idle without using a “hold reverse” key command. However, you will need a program like FSUIPC to do so. I managed to successfully map the full reverse and idle reverse “detents” on my TCA Quadrant to full reverse and idle reverse in the PMDG737. The way I did it though only only allows me full reverse or idle reverse, nothing in between.

I set a button on my joystick to " hold throttle reverse thrust". When you press the button, your throttle will adjust the reversers and you can adjust the amount of reverse thrust. You can see the reversers move. Release the button and you back to normal thrust.

[HighFlier]

I set a button on my joystick to " hold throttle reverse thrust". When you press the button, your throttle will adjust the reversers and you can adjust the amount of reverse thrust. You can see the reversers move. Release the button and you back to normal thrust.

I am aware of your way of doing it as well, but I personally don’t like it. I do not want to move my throttles forward, in any capacity, for reverse thrust. My throttle has an idle detent, and then a reverse zone. If you lift up the finger lifts you can go past the idle detent and into that reverse zone. As a result of my throttle design, I want to engage reverse thrust when moving my throttles backwards into that zone. There is no way to natively do that in MSFS, and hence I turned to FSUIPC.

[jrw4]

No doubt there are a number of ways to achieve a similar goal. Much depends on the way the one's hardware controls are configured. Very few of us will have hardware that corresponds to the actual Boeing throttle controls, so it's all a compromise.

[Aeromar]

The way I did it though only only allows me full reverse or idle reverse, nothing in between.

That's not really an issue. We don't use intermediate positions in the real airplane, except maybe in extremely slippery runways and taxiways in case the airplane starts skidding out of control where we would even use asymmetric reverse if needed (I've only done that in training sessions in the sim).

In the real airplane we either use first detent (idle reverse) or second detent (the reverse thrust setting that OPT calculations are made with). We can also use 3rd detent which provides reverse thrust beyond OPT performance calculation when necessary. This is why not having an axis for reversers isn't really that big a deal. I have a WinWing Orion 2 throttle console and I've set up a "software" button for using first detent reverse. This soft button is built in the low limit of the thrust lever range for shutting down the F/A-18 engines that the console is based on.

[pappy17]

The behavior of the aircraft, its physics during what compdiff writes about, is incorrect and should be fixed.

[Crabby]

Can't be fixed by PMDG. This is what the in-sim assignments do. If you want that changed you can use Axis and Ohs, SpadNext or FSUIPC to do so. If you want to beat your head against the "fix it wall", then ASOBO is the target for stuff like this.

[pappy17]

You still don't understand Crabby.. It's not about assigning keys, axis etc. It's about "If traveling say 5 knots in reverse and hit F1, instantly changes to forward 5 knot." Other planes don't have this problem.

[compdiff]

Thanks mate. Perfect. I should of put a video on.
But this is exactly what I mean.

Thanks for replicating it instead of just assuming! you are a god! lol

[Ephedrin]

You still don't understand Crabby.. It's not about assigning keys, axis etc. It's about "If traveling say 5 knots in reverse and hit F1, instantly changes to forward 5 knot." Other planes don't have this problem.

PMDG model their aircraft fully operative and behaving as correctly as possible within limitations of their purpose. You're supposed to throttle down your reversers at around 60 and close them when you taxi off the high speed exit at the latest. Going backwards is certainly not part of that so don't expect correct behaviour doing such things. The aircraft (software) is a large cooperative system of different things working together, engines and thrust, ground model, systems behind the engines that need to match so a correct simulation of these systems is guaranteed. If you go and try to do extended negative g maneuvres (as an extreme example) you'll see erratic responses.

Out of honest curiosity: What other aircraft do you mean?

[Falcon99]

Let's go back to being simple. This will happen if you DO NOT throttle to idle before closing the reversers while backing up. That's it. Hitting F1 is doing both, closing the reversers and setting throttle to idle at the same time. It takes time for the engines to spool down to idle. So, hitting F1 is not the proper procedure. If you want to back up following the correct procedure, make specific assignments for the throttle axis and reversers. Set throttle axis to idle, wait for the engines to spool down to idle, close the reversers. There is really nothing else to discuss, the model is working as designed.

If you have a concern after you have tried this, then please open a ticket with PMDG for further discussion concerning an enhancement request outlining why you believe the model behavior needs to be modified.

[frank1223]

You still don't understand Crabby.. It's not about assigning keys, axis etc. It's about "If traveling say 5 knots in reverse and hit F1, instantly changes to forward 5 knot." Other planes don't have this problem.

Sorry to say but this behaviour does look against real world physics, regardless of going reverse idle or not. Tried the exact same procedure with Asobo’s 747 A320 and even Flybywire’s Neo doesnt behave like this.

Zhemin Cao

[pappy17]

Thank you, you are the first person here who understands what I mean.

[bobsk8]

Sorry to say but this behaviour does look against real world physics, regardless of going reverse idle or not. Tried the exact same procedure with Asobo’s 747 A320 and even Flybywire’s Neo doesnt behave like this.

Zhemin Cao

I never judge anything by comparing it to a default aircraft in a flight sim.

[DDowns]

You still don't understand Crabby.. It's not about assigning keys, axis etc. It's about "If traveling say 5 knots in reverse and hit F1, instantly changes to forward 5 knot." Other planes don't have this problem.

Your problem here is you are using the reverse thrust to push back. This is probably prohibited, not the least because of the very high probability of FOD not to mention the lack of rear view mirrors.

[jrw4]

There seems to be an implicit assumption by some that the keyboard shortcuts provided by MSFS would all work as expected and with the proper physics in add-on aircraft such as the PMDG 737 family. Perhaps that should be, or maybe not, but why single out the F2/F1 duo? I just tried to start the engines on the 737 with the CTRL-E combination and it failed completely, while it works just fine on the default C172.

The only way that F1/F2 will get "fixed" is to submit this apparent discrepancy via a support ticket. Feel free to include CTRL-E as well. I imagine that the folks at PMDG will put these requests into their priority queue for programming resources along with the UFT, 737 MAX, enhanced cabin sounds and textures, etc., etc. In the meanwhile, there certainly appear to be easily implemented alternatives to F1/F2 that will provide the desired reverser deployment while not requiring SPAD, FSUIPC, etc.

Best wishes.

[compdiff]

Thanks JRW4, wasn't sure of the correct why to do the bug. Ill launch a ticket as it is an issue.


It is definitely against the laws of physics. Even the people that didn't try to replicate in this forum should try to and they will see what is meant.

Thanks Pappy for the video. I should have done that, but it is perfect. Its like reverse = 5 knots, flick switch, forward = 5 knots. Nothing in between.

[compdiff]

Also

Thanks to the two most experience people here, captain Kevin (first name and last name) and emi (first name and last name) for not really being too polite or not even trying to understand the problem.

Don’t stress too much about my comments here as I will make sure to avoid using the forums to see what to do.

not very good atmosphere and first inpressions.

hopefully they do not not represent PMDG in any official capacity.

[frank1223]

Some of the folks here are being so defensive when they don’t even bother checking out the demonstration, and yet don’t realise PMDG do not behave the same way in P3D or even in FSX.

[Captain Kevin]

It wasn't a case of people being so defensive as much as it was the original issue had been misunderstood. Having read the later posts, it would appear that the original poster was trying to operate the aircraft in a manner in which it would normally never be operated, which was why none of us thought there was an issue in the first place. Once somebody posted a video, the problem was now understood. That said, I tested it out in both the 737 and 747 in P3D this morning and can confirm that the same thing happens if the aircraft is operated in such a manner.

[bobsk8]

Also

Thanks to the two most experience people here, captain Kevin (first name and last name) and emi (first name and last name) for not really being too polite or not even trying to understand the problem.

Don’t stress too much about my comments here as I will make sure to avoid using the forums to see what to do.

not very good atmosphere and first inpressions.

hopefully they do not not represent PMDG in any official capacity.

EMI is an airline pilot who makes all the training videos on the 737. Maybe you should try growing up.

[Captain Kevin]

Also

Thanks to the two most experience people here, captain Kevin (first name and last name) and emi (first name and last name) for not really being too polite or not even trying to understand the problem.

Don’t stress too much about my comments here as I will make sure to avoid using the forums to see what to do.

not very good atmosphere and first inpressions.

hopefully they do not not represent PMDG in any official capacity.

Okay, first of all, both Emi and myself do, in fact, have our first and last names in our signatures, so maybe try looking closer first before you try to accuse us of not following the rules. Second of all, I tried to help. If I didn't understand the problem, instead of turning around and telling me I didn't try to understand the problem, maybe try helping me to understand the problem. I'm autistic. I don't process things, and it's easy for me to see things a different way, possibly different from what you intended. Obviously, what you were trying to say and what I thought you were trying to say were two completely different things, so instead of trying to get at me for failing to understand the problem, maybe try clarifying it instead. Mind you that was the only time I responded in your post up until this point, so you really can't tell me I deliberately didn't try to understand the issue. In any event, I'm not employed by PMDG, I'm just a customer, just like you and most people here.

[compdiff]

I shall buy the first beer then! And the second and the third.

Maybe try to replicate the issue first before anything. I should have put a video, but a newbie getting attacked and then getting told I was doing wrong when it is indeed a coding/math issue, will of course make me defensive and annoyed. Espeically 2 higher ups in the forum. That really sets the tone doesn't it?

Will also the buy the fourth beer. but none for bobsk8. He can be designated driver.

[Captain Kevin]

The thing is, I don't see where anybody attacked you, all we were trying to do was help. If somebody had called you an idiot in the process, that would have been one thing, but nobody did that. As far as trying to replicate the issue first before anything, it would have been difficult to try that when I had already misunderstood the issue in the first place, and as it turns out, everybody else was thinking the same thing I was. Most of us wouldn't have thought you were using the thrust reversers to actually move the airplane backwards because this isn't normal procedure for a number of safety reasons. Therefore, trying to replicate the issue as we understood it initially wouldn't have yielded any results. In any event, I don't own the 737 for MSFS, so I have no way of trying it. But just for giggles, I tried it with the 737 in P3D. If I try to operate the airplane in a manner that most of us thought you were doing it, no issue. If I try to operate it in the manner that you were doing it, the issue exists, so I do see the problem. I also tried it with the 747-400 in P3D, same thing. I would try it in the 777, but I don't have time for that right now since I need to take my mom to urgent care, but the results would probably be the same. The question is why were you trying to use the thrust reversers to move the airplane backwards in the first place.

[cmakris]

Gents,

Can you please be more polite otherwise the lock will come...

compdiff you need to follow the rules if you want to participate in the forum. Please sign you full name first and last from now on as per rules, which you agreed on upon registering in the forum.

[HighFlier]

That's not really an issue. We don't use intermediate positions in the real airplane, except maybe in extremely slippery runways and taxiways in case the airplane starts skidding out of control where we would even use asymmetric reverse if needed (I've only done that in training sessions in the sim).

In the real airplane we either use first detent (idle reverse) or second detent (the reverse thrust setting that OPT calculations are made with). We can also use 3rd detent which provides reverse thrust beyond OPT performance calculation when necessary. This is why not having an axis for reversers isn't really that big a deal. I have a WinWing Orion 2 throttle console and I've set up a "software" button for using first detent reverse. This soft button is built in the low limit of the thrust lever range for shutting down the F/A-18 engines that the console is based on.

As I understand it though, full reverse in the simulator is the third detent, correct? If that is correct then I am always applying more reverse thrust than what the OPT is calculating with, although I don’t really mind.

[Aeromar]

As I understand it though, full reverse in the simulator is the third detent, correct? If that is correct then I am always applying more reverse thrust than what the OPT is calculating with, although I don’t really mind.

Yes. 2nd detent is usually around 76% N1. If you're getting more than that and over 80%N1 then you're in 3rd detent.

I wish there was a way to operate the reversers with just buttons and assign those buttons to the range of your reverser axis (in case you have one). You could have one button function for each detent and that would be operationally far more realistic than having a continuous axis range for the reversers. This would confuse people more than the new realistic parking brake application though.

[bobsk8]

https://www.flaps2approach.com/journal/2022/9/9/reverse-thrust-procedure.html

[Captain Kevin]

In the real airplane we either use first detent (idle reverse) or second detent (the reverse thrust setting that OPT calculations are made with). We can also use 3rd detent which provides reverse thrust beyond OPT performance calculation when necessary. This is why not having an axis for reversers isn't really that big a deal. I have a WinWing Orion 2 throttle console and I've set up a "software" button for using first detent reverse. This soft button is built in the low limit of the thrust lever range for shutting down the F/A-18 engines that the console is based on.

Interesting. I didn't know the second and third detents even existed.