Go-around performance issues

[skyrider 0]

LOL My words of the day... finally "managed" to fly such go-around as well - been at least five attempt until I was finally there. First approach was a complete lockup when hitting TOGA. Interesting, second lockup, and both post HF4 install... bad sign? Second approach at least resulted in an actual go-around, but I forgot about my totally exaggerated force feedback joystick always throws the stick around like crazy when toggling the gear, resulting in AP disconnection and loss of TOGA pitch mode. [...] Finally it worked, and as you say, speeds were spot on (MTOW this time), also compared to manual again. Makes a lot more sense now. On my journey however the thing never stopped to amaze me. Without spoiling the fun, I will first let you have a close look at the following: And no, I'm neither talking about the rather liberal interpretation of "altitude HOLD", nor my abbreviated final approach (you can tell I was getting frustrated with all the futile go-around attempts...). Instead, my unshakable system understanding has always been that one can have one active mode per AFDS channel, plus an armed mode. Certainly less, but definately not more. Apparently though, the NGX has provisions for arming two pitch modes at a time - otherwise I see no explanation for G/S and V/S sitting perfectly next to each other, as opposed to centered as they would usually be. Or it's me, once again, and I'm missing another major point here. In fact I can even find it in the manual, but without further explanation. Enlighten me, whoever can come to rescue! Oh, got another one. Under certain circumstances (will have to investigate further, once again... sigh) it's impossible to cancel the wailer during the go-around. Probably during dual-channel operation, will check tomorrow. Anyways, you can hammer your Z button, it will only restart the wailer and the flashing red A/P light on the ASA won't exstinguish by any means. This behavior takes place until for example TOGA pitch modes gets replaced by ALT ACQ. Hitting Z then immediately silences the wailer, just as usual. I believe reclycling the FDs (and hence quitting TOGA mode) could also work. First I need to find a way to repdroduce though.

"Curiouser and curiouser" said Alice. I also believe that you can only have one engaged mode & one armed mode per each sector on the FMA. I can see how you have achieved this from your pic but I'm not sure that this is supposed to happen for real! Regarding the 'wailer' it should be possible to cancel it with a second press of the AP disconnect button or by pressing the red light. I can't think why it should continue to sound if you have done this. You are not confusing this with the gear warning horn by any chance? Doug

[badderjet 181]

I also believe that you can only have one engaged mode & one armed mode per each sector on the FMA. I can see how you have achieved this from your pic but I'm not sure that this is supposed to happen for real! Regarding the 'wailer' it should be possible to cancel it with a second press of the AP disconnect button or by pressing the red light. I can't think why it should continue to sound if you have done this. You are not confusing this with the gear warning horn by any chance?

That were my thoughts as well. But then I just entered 737 "g/s v/s" on Google and was shocked to get actual results. Immediately jumped into the FCOM, and behold! - 4.10.26 indeed backs up what I see. And that is even without IAN, as there is also G/P V/S, which obviously applies to IAN equipped aircraft only. However, that's about all of reference I could find. No further talking about what on earth this armed "mode" should be or when it would be a factor. Because becoming active as a green "mode" annunciation is certainly impossible. And about the wailer, yes I am very confident I don't mix up anything here. I am aware of the ways to usually cancel it, and what it does is basically, once you hit 'Z' it will set off the wailer once again. Like you know, the sound is intermittent, sort of, and hence not continuous. Hitting 'Z' will kind of 'rewind' and replay the sound, if you will (but again continuing forever). At least it won't stop, that's the key fact here, and the ASA light also continues to flash.As I reckoned before, this seems somehow related to TOGA pitch mode, as entering another pitch mode (like ALT ACQ) or quitting TOGA by recycling FDs will restore normal behavior. Hit 'Z' one more time and everything shuts up as it should. Very bizarre, and I smell bug somewhat.

[skyrider 0]

That were my thoughts as well. But then I just entered 737 "g/s v/s" on Google and was shocked to get actual results. Immediately jumped into the FCOM, and behold! - 4.10.26 indeed backs up what I see. And that is even without IAN, as there is also G/P V/S, which obviously applies to IAN equipped aircraft only. However, that's about all of reference I could find. No further talking about what on earth this armed "mode" should be or when it would be a factor. Because becoming active as a green "mode" annunciation is certainly impossible. And about the wailer, yes I am very confident I don't mix up anything here. I am aware of the ways to usually cancel it, and what it does is basically, once you hit 'Z' it will set off the wailer once again. Like you know, the sound is intermittent, sort of, and hence not continuous. Hitting 'Z' will kind of 'rewind' and replay the sound, if you will (but again continuing forever). At least it won't stop, that's the key fact here, and the ASA light also continues to flash.As I reckoned before, this seems somehow related to TOGA pitch mode, as entering another pitch mode (like ALT ACQ) or quitting TOGA by recycling FDs will restore normal behavior. Hit 'Z' one more time and everything shuts up as it should. Very bizarre, and I smell bug somewhat.

I can see the "G/P V/S" option in the FCOM but nothing about the "G/S V/S" combination. I'm not sufficiently familiar with IAN to comment but my guess is that when you arm the pitch mode you get the "G/P V/S" together. What you seem to have is "G/S" armed by pressing the "APP" switch & "V/S" armed by setting a new altitude in the altitude window which causes "V/S" to arm normally. But I have never seen both of these showing at the same time & can't say for sure if it is technically possible. Regarding the wailer I suspect it is a bug. I have experienced many strange issues with the NGX, some are repeatable, some are not. But I have the same kind of experience in real sims! Doug

[zazaboeing 15]

...What you seem to have is "G/S" armed by pressing the "APP" switch & "V/S" armed by setting a new altitude in the altitude window which causes "V/S" to arm normally. But I have never seen both of these showing at the same time & can't say for sure if it is technically possible...

That's exactly what it happens in the real thing Doug, this is correctly modeled in the NGX.

[skyrider 0]

That's exactly what it happens in the real thing Doug, this is correctly modeled in the NGX.

Thanks Rafael, that's good to know. You learn something new every day (almost)! Doug

[kevinh 409]

And about the wailer, yes I am very confident I don't mix up anything here. I am aware of the ways to usually cancel it, and what it does is basically, once you hit 'Z' it will set off the wailer once again. Like you know, the sound is intermittent, sort of, and hence not continuous. Hitting 'Z' will kind of 'rewind' and replay the sound, if you will (but again continuing forever). At least it won't stop, that's the key fact here, and the ASA light also continues to flash.As I reckoned before, this seems somehow related to TOGA pitch mode, as entering another pitch mode (like ALT ACQ) or quitting TOGA by recycling FDs will restore normal behavior. Hit 'Z' one more time and everything shuts up as it should. Very bizarre, and I smell bug somewhat.

Hitting Z is not the same as using the AP disconnect button on the yoke. It is an AP engage/engage toggle. Works OK with a simple MSFS autopilot, but hitting Z repeatedly is going to confuse the NGX's complex autopilot. To get the correct response you need to map the NGX AP disconnect button to a key or joystick button. You can do this via the set up pages in the MCDU. I have mine mapped to CTRL Z. That way you get the correct response. first push disconnects the AP, second push silences the wailer. Kevin Hall

[badderjet 181]

Hitting Z is not the same as using the AP disconnect button on the yoke.

Well, it is for me.

It is an AP engage/engage toggle. Works OK with a simple MSFS autopilot, but hitting Z repeatedly is going to confuse the NGX's complex autopilot. To get the correct response you need to map the NGX AP disconnect button to a key or joystick button. You can do this via the set up pages in the MCDU. I have mine mapped to CTRL Z. That way you get the correct response. first push disconnects the AP, second push silences the wailer.

I'm pretty convinced something very different confuses the NGX's AP here - probably it confuses itself.Should've mentioned earlier though that my Z was of course mapped to the disco button, my bad (my CMD A is CTRL+SHIFT+Z here). Mistakenly presumed it was clear from my explanations. The "correct response" would be a silent wailer and an exstinguished ASA light when I hit the button. This is not happening under said conditions.

[renehermans 1]

For our excercise we receive from ATC ´´ after touch and go runway hdg; ´´ We have to do a ILS landing with only one Nav available, and a roll out on the ground for 5 seconds.To avoid that the FMC becomes empty after the T/G, I fill in a waypoint in the environnementlHow I do this manoeuvre At 30 ft I disconnect the autopilot and A/T; make a manual landing with a roll out for 5 sec. Retract the flaps and advance the throttles .BUT Is that the correct procedure ?

[skyrider 0]

For our excercise we receive from ATC ´´ after touch and go runway hdg; ´´ We have to do a ILS landing with only one Nav available, and a roll out on the ground for 5 seconds.To avoid that the FMC becomes empty after the T/G, I fill in a waypoint in the environnementlHow I do this manoeuvreAt 30 ft I disconnect the autopilot and A/T; make a manual landing with a roll out for 5 sec. Retract the flaps and advance the throttles .BUT Is that the correct procedure ?

As far as handling is concerned we do the following: PF (RHS): After touchdown lower the nosewheel onto the runway & keep the aircraft on the centreline using rudder pedals. Stands up the thrust levers to the vertical position. PM (LHS): Sets F15, checks speedbrake down, resets stab trim, sets go around thrust/presses TOGA (depending on whether autothrottle/FD in use), calls "Rotate" at Vref. Have fun! Doug

[badderjet 181]

PF (RHS): After touchdown lower the nosewheel onto the runway & keep the aircraft on the centreline using rudder pedals. Stands up the thrust levers to the vertical position.

STAND'M UP!!! [...] PUSH'M UP!!! Just love it. BTW if anyone cares, here's one way to do it.

[JoeDiamond 67]

Well, it is for me. I'm pretty convinced something very different confuses the NGX's AP here - probably it confuses itself.Should've mentioned earlier though that my Z was of course mapped to the disco button, my bad (my CMD A is CTRL+SHIFT+Z here). Mistakenly presumed it was clear from my explanations. The "correct response" would be a silent wailer and an exstinguished ASA light when I hit the button. This is not happening under said conditions.

I had the same problem with the autopilot not disconnecting. Then I discovered there are two different entries for the autopilot disconnect button in the PMDG key mapping options. You want the one labeled "autopilot disconnect" not "autopilot button". The correct one is the second to last option on the auto flight page. Once I mapped the button to the proper option everything works as it should. Pressing the disconnect button after TOGA now silences the wailer as it should.

[badderjet 181]

Well, as I tried to explain above, I don't say my button doesn't work. In fact, it works all the time. There's just this one condition, during some of the go-arounds, where it won't work. Because you brought it up I just checked it, but I was pretty sure the assignment was correct and it turned out it was. My Z I linked to the button that is on the yoke of the real counterpart. That one disco's all APs should they be engaged, and cancels all warnings upon further button presses. Just for this special go-around case (yet to be reproduced) it doesn't work. It's like the AP is somewhat off, but the warning is locked on and can only be "reset" (and I do NOT mean "turned off" by that, I mean in fact "replay" the wailer over and over, playing forever). Actual silencing, as indicated before, is only possible by exiting TOGA pitch mode one way or another.

[badderjet 181]

Regarding the wailer I suspect it is a bug. I have experienced many strange issues with the NGX, some are repeatable, some are not. But I have the same kind of experience in real sims!

What, bugs? What kind of bugs do they have? I know there's something broken every now and then, but what else would that be? Maybe they need an SP too...

That's exactly what it happens in the real thing Doug, this is correctly modeled in the NGX.

Thanks Rafael, good to know! However:

I can see the "G/P V/S" option in the FCOM but nothing about the "G/S V/S" combination. I'm not sufficiently familiar with IAN to comment but my guess is that when you arm the pitch mode you get the "G/P V/S" together. What you seem to have is "G/S" armed by pressing the "APP" switch & "V/S" armed by setting a new altitude in the altitude window which causes "V/S" to arm normally. But I have never seen both of these showing at the same time & can't say for sure if it is technically possible.

I didn't really see that in the first place. But you are right, with an armed APP mode (no matter IAN or ILS) and active ALT HOLD, changing MCP alt would get the double arm with V/S.I still don't get the reason for it. I can't see any condition how with ALT HOLD active, and a glide path/slope mode armed, AND vertical speed armed, how vertical speed would EVER become active - it never would, or what am I missing here? Once I hit the glide path/slope, that mode engages, killing everything else. Why would V/S arm that way in the first place? Furthermore, in case anyone wants to try it, the double arm will only be present if you set MCP altitude one hundred feet off your current alt (one click on the knob). Going beyond will make it go out again. Very confusing. Rafael or anyone, if you could chime in again here, I'd appreciate it.

[skyrider 0]

What, bugs? What kind of bugs do they have? I know there's something broken every now and then, but what else would that be? Maybe they need an SP too... Thanks Rafael, good to know! However: I didn't really see that in the first place. But you are right, with an armed APP mode (no matter IAN or ILS) and active ALT HOLD, changing MCP alt would get the double arm with V/S.I still don't get the reason for it. I can't see any condition how with ALT HOLD active, and a glide path/slope mode armed, AND vertical speed armed, how vertical speed would EVER become active - it never would, or what am I missing here? Once I hit the glide path/slope, that mode engages, killing everything else. Why would V/S arm that way in the first place? Furthermore, in case anyone wants to try it, the double arm will only be present if you set MCP altitude one hundred feet off your current alt (one click on the knob). Going beyond will make it go out again. Very confusing. Rafael or anyone, if you could chime in again here, I'd appreciate it.

I can reproduce this in FSX with the NGX. I will try it out the next time I am in a RW Level D sim (soon). The reason I have not seen this combo before is that it is not normal to have a different altitude to your platform altitude set in the altitude window at this stage of the approach. Normally you will be at, or descending to the platform altitude as set in the altitude window so you will not see V/S armed. Once you have captured the glideslope (G/S GREEN) you will reset the altitude in the window to that required by the missed approach procedure if different. Sadly RW sims are not perfect either. Despite continuous quality checks & updates they still exhibit various inaccuracies & can misbehave like any other computer based device! This can make things very confusing, to say the least! Doug

[zazaboeing 15]

What, bugs? What kind of bugs do they have? I know there's something broken every now and then, but what else would that be? Maybe they need an SP too... Thanks Rafael, good to know! However: I didn't really see that in the first place. But you are right, with an armed APP mode (no matter IAN or ILS) and active ALT HOLD, changing MCP alt would get the double arm with V/S.I still don't get the reason for it. I can't see any condition how with ALT HOLD active, and a glide path/slope mode armed, AND vertical speed armed, how vertical speed would EVER become active - it never would, or what am I missing here? Once I hit the glide path/slope, that mode engages, killing everything else. Why would V/S arm that way in the first place? Furthermore, in case anyone wants to try it, the double arm will only be present if you set MCP altitude one hundred feet off your current alt (one click on the knob). Going beyond will make it go out again. Very confusing. Rafael or anyone, if you could chime in again here, I'd appreciate it.

It becomes active as soon as you hit the VS thumbwheel, and GS stays as the only "armed" mode. You can use this feature to "soften" the GS capture while it approaches 1 1/2 dot from center, with lets say 300 ftpm descent.