Archived

This topic is now archived and is closed to further replies.

ApacheHunter

Red boxes around N1 values

Recommended Posts

I'm currently in the descent phase of my flight from Washington Dulles Intl. to Amsterdam Airport Schiphol. During the climb phase I noticed red boxes had appeared around the N1 values on the upper EICAS display. They've been there troughout the flight and still are there. What causes these red boxes and how can I get rid of them?

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

The only time I'v seen this is in the MD11 and 747 products, when I haven't used Autothrottle/TOGA for takeoff and accidently missed the click and jammed the (hardware) throttle forward to the null zone I have up top. That tends to give an N1% value of over 100% (116% is the best I've seen in the 747 yeehaw) This is a higher power setting than the engines can handle for any significant time, and the red boxes will come on and never go away.

 

In real life this happens too, and the only way to reset the red boxes is to get an engineer to do an engine inspection and reset the system. Red box is there so it's pretty obvious there's something that went on that needs checking out, and the next crew to get the aircraft will notice too, even if it wasn't written up in the aircraft logbook.

 

In FS, I think this can also happen when the weather engine injects bad weather too. (like the infamous +45°C at FL380 that FSinn likes to inject)

 

So that's the 2 reasons I can think of that made this happen:

1: Autothrottle disconnected and throttles manually pushed up to/past max power for a long while (more than 60 seconds)

2: Weather was ridiculously and unrealistically hot in the ISA+90°C range.

 

There might be a possibility of no derate takeoffs at really high temperatures getting it there too, though the FADEC with Auto throttle on shouldn't allow that.

 

Of course some kind of failure (simulated FADEC failure, engine control module failure, engine surge, compressor stall etc) might overspeed the N1 too..

Share this post


Link to post
Share on other sites

Like hopskip says if you was in manual mode maybe you exceed the N1speed limit not likely to happen with auto throttle engage or a simulated failure this apply not only on the triple seven applies for the 737,747, MD11 also...or maybe the insane condition of the weather engine of fsinn.

 

Mitchel

Share this post


Link to post
Share on other sites

Had this happen to me the other  day,  thought it  would  trigger  an alert or  something but  seeing the red boxes  appear  is  enough of  an alert -_-

Share this post


Link to post
Share on other sites

Had it happen when I was taking off from Dubai as well. At some point during takeoff autothrottle disengaged and the N1 went sky high because I had the throttles pushed all the way forward. Maybee just back the off a tad on takeoff( I was using TOGA)

 

I'm sure this shouldn't happen in the real thing with AT engaged like it does in the sim because the throttle will suddenly jump to where ever you have it if AT drops for any reason. In my case all the way forward thus overspeeding the engines.

 

No way around it unless you have a $3k motorized throttle:/

Share this post


Link to post
Share on other sites

I'm sure this shouldn't happen in the real thing with AT engaged like it does in the sim because the throttle will suddenly jump to where ever you have it if AT drops for any reason.

 

 

Only way you could do it in real world would be to reach out with your hand and physically push the thrust levers all the way forward and hold it there with your hand.

 

Of course the throttle won't 'suddenly jump to where ever you have it', because it is where it is, being a physical set of objects.

Share this post


Link to post
Share on other sites

I landed the plane and then the red boxes disappeared. Still, I don't understand why they appeared anyway because the A/T never went off and I also didn't have my hardware throttle levers all the way forward. As far as I know, the engines didn't overspeed. The red boxes just appeared out of nowhere. Maybe it has to do with starting this flight from a saved situation, which I had not done before with the triple seven.

Share this post


Link to post
Share on other sites

This happened to me on takeoff. I used TOGA as usual but when the A/T went to HOLD mode the thrust went to where my throttle input was, maximum. At thrust reduction altitude the A/T went to climb thrust, controlling the thrust levers again. Leaving me with red boxes around the N1 and EGT indications.

Share this post


Link to post
Share on other sites

 

 


No way around it unless you have a $3k motorized throttle:/

 

If you are willing to sacrifice a touch of visual realism, you can actually. Just turn on the option to always show the physical throttle position, then while A/T is engaged match the physical throttle position indicator to the A/T commanded throttle position. Then if A/T is ever disengaged for any reason, you'll be commanding the same thrust setting.

Share this post


Link to post
Share on other sites

 

 


My Logitech X3D only sends information when the hardware throttles are moving but I'm not sure if that is the case for all throttles.h

I believe, as far as FS is concerned, this is the norm... 

 

of course as soon as you get some noise... the FS would not know whether you are moving the throttle ever so slightly (or in some worse cases not at all slightly) or if it is just electronic noise.

Share this post


Link to post
Share on other sites

I believe, as far as FS is concerned, this is the norm... 

 

of course as soon as you get some noise... the FS would not know whether you are moving the throttle ever so slightly (or in some worse cases not at all slightly) or if it is just electronic noise.

 

I put a Null zone in my throttle via FSUICP, so "fully forward" and "Fully aft" are actually outside the movement range.

 

That said I'v heard some people who can't set a null zone like this and it instead puts a null zone in the mid-range, so pushing the throttle from idle to full, it passes an area around 50% where a large amount of movement results in no %N1 change. Which is bizzare and about as useful as a flyscreen on a submarine, ashtray on a motorbike etc.

Share this post


Link to post
Share on other sites

EEC should prevent you exceeding the red line. What's more likely is that you ran greater than max continuous thrust for more than 5 mins.

 

Where you in VNAV?

Share this post


Link to post
Share on other sites

How about advancing the throttles to 55% N1 and then engage toga, that way your physical throttle should not be full forward and won't cause this issue.

Share this post


Link to post
Share on other sites

 

 


That said I'v heard some people who can't set a null zone like this and it instead puts a null zone in the mid-range, so pushing the throttle from idle to full, it passes an area around 50% where a large amount of movement results in no %N1 change. Which is bizzare and about as useful as a flyscreen on a submarine, ashtray on a motorbike etc.

 

I think if you set up "Null zone" in FS, it is globally setup for the stick, i.e. centered, but there is another option to make a "nullzone" at the ends. (I think so at least)

Share this post


Link to post
Share on other sites

I think if you set up "Null zone" in FS, it is globally setup for the stick, i.e. centered, but there is another option to make a "nullzone" at the ends. (I think so at least)

 

I see axes for Aeleron/Elevator, Rudder and Throttle as 3 different sliders with their own sensitivity and null zone settings. I have my throttle set up with 100% (slider full right) sensitivity and about a 1/5th sized Null zone.

Share this post


Link to post
Share on other sites

Hi all,

 

This is something I have experienced too.

 

In the Tutorial the recommended PMDG method is to bring the engines up to 55% then to hit the TOGA button and while your engines are in THR REF mode push your physical throttles all the way forward, which in my case did bring up the N1 limit exceeded red box warnings. I found once on, if you clicked "recall" you could extinguish the warning boxes until you hit "recall" next time when they would come back on. I believe in real life these stay on as a warning to  any other crew taking over the plane that the N1 limit has been exceeded and the aircraft hasn't been inspected.

 

The tutorial recommends leaving the physical throttles at max until you start the descent when the throttles go to "idle" mode and then you should return the physical throttles to idle too.

 

Physical throttles being the ones on your throttle quadrant/joystick etc.

 

Hope this helps.

Share this post


Link to post
Share on other sites

EEC should prevent you exceeding the red line. What's more likely is that you ran greater than max continuous thrust for more than 5 mins.

 

Where you in VNAV?

 

AFAIK the EEC should prevent you from exceeding max continuous thrust too.

How about advancing the throttles to 55% N1 and then engage toga, that way your physical throttle should not be full forward and won't cause this issue.

In my case that is exactly what I was doing. But if you leave the throttles at that position they may follow that input in HOLD. You have to set the throttles to max to avoid that (or switch off the throttle A/T override). I only got exceedances like this on one occasion though. On every takeoff since it's behaved perfectly.

Share this post


Link to post
Share on other sites

Hi all,

 

This is something I have experienced too.

 

In the Tutorial the recommended PMDG method is to bring the engines up to 55% then to hit the TOGA button and while your engines are in THR REF mode push your physical throttles all the way forward, which in my case did bring up the N1 limit exceeded red box warnings. I found once on, if you clicked "recall" you could extinguish the warning boxes until you hit "recall" next time when they would come back on. I believe in real life these stay on as a warning to  any other crew taking over the plane that the N1 limit has been exceeded and the aircraft hasn't been inspected.

 

The tutorial recommends leaving the physical throttles at max until you start the descent when the throttles go to "idle" mode and then you should return the physical throttles to idle too.

 

Physical throttles being the ones on your throttle quadrant/joystick etc.

 

Hope this helps.

 

I thought I did that once, but I suspect I didn't get the clickspot right, and instead of the throttles getting the instruction to go into autothrottle+TOGA they got nothing except a hardware throttle signal to go all out 114%N1

Share this post


Link to post
Share on other sites