Sign in to follow this  
captain420

PMDG 777 not automatically switching to CRZ after CLB

Recommended Posts

I'm not sure what I'm doing wrong, but after my plane reaches T/C isn't the CDU suppose to automatically switch to CRZ mode? Instead it keeps saying CLB. I don't ever recalling it acting this way.

Share this post


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

I think this is an airline option - you will find it somewhere in the options.  Check the manual.

 

Cheers,

Share this post


Link to post
Share on other sites

Hi,

 

First thing before asking on the forum, check the manuals:

Introduction manual p83

Share this post


Link to post
Share on other sites

If you are talking about the thrust limits on the EICAS display, that's an option. However with the CDU, I don't know if that's because the vnav isn't set up correctly or what.

 

Also, if you have any questions, feel free to come here. Whether you read the manuals or not. The manuals for this type of airplane are huge and it's something that could take quite some time. Not everyone has time to learn an airplane like this. Let's be real, people go through training programs for this airplane that are full time hrs for a month at the least.

 

That being said, come on by, ask questions and let us help you understand this airplane.

Share this post


Link to post
Share on other sites

Hi,

 

Reading again the whole thread, a doubt crossed my mind and I may have answered too quickly.

Are you talking about the CLB/CRZ thrust limit in cruise or the cruise VNAV ACT ECON CRZ page of the CDU?

Share this post


Link to post
Share on other sites

Thanks a lot Matthew, I really appreciate that. I'm not really doing anything different when programming the CDU before flight. When I use X-Plane 10's FlightFactor 777, it doesn't give me problems. the CDU will automatically switch from CLB to CRZ after it reacher T/C. But I'm not sure why it's not doing this in PMDG's 777.

 

I've looked at page 83 of the introduction manual and couldn't find anything related to this.


Hi,

 

Reading again the whole thread, a doubt crossed my mind and I may have answered too quickly.

Are you talking about the CLB/CRZ thrust limit in cruise or the cruise VNAV ACT ECON CRZ page of the CDU?

 

I'm referring to the status display in the EICAS... where it says CLB on the top... that should switch to CRZ after your plane hit's T/C but mine remains in CLB forever.

Share this post


Link to post
Share on other sites

Aaron,

 

My apologies, I think I misread your issue. The FMC should change from ACT ECON CLB to ACT ECON CRZ when it reaches the altitude set in the CRZ ALT box of the PERF INIT page.
Are you sure that the altitude you set on the MCP and the one you set in the PERF INIT page of the CDU are the same?


 

 


I'm referring to the status display in the EICAS... where it says CLB on the top... that should switch to CRZ after your plane hit's T/C but mine remains in CLB forever.

 

Aaron,

 

I hope my first post was not rude, it is not intended.
But the solution is indeed in page 83 of the introduction manual: FMS CRZ PHAS THR LIM.

If it is set to CLB, then the thrust limit in cruise will remain on CLB. If you want it to switch to CRZ, then you have to set the option to CRZ.

  • Upvote 1

Share this post


Link to post
Share on other sites

Yes CRZ ALT in my CDU is set for FL360

 

and also on my MCP dialed to 36000 as well.

Share this post


Link to post
Share on other sites

Ok, that's fine but check the second part of my post for the thrust limit in cruise (the CLB/CRZ displayed on top of the upper EICAS).

Share this post


Link to post
Share on other sites

Thanks a lot Matthew, I really appreciate that. I'm not really doing anything different when programming the CDU before flight. When I use X-Plane 10's FlightFactor 777, it doesn't give me problems. the CDU will automatically switch from CLB to CRZ after it reacher T/C. But I'm not sure why it's not doing this in PMDG's 777.

 

I've looked at page 83 of the introduction manual and couldn't find anything related to this.

 

 

I'm referring to the status display in the EICAS... where it says CLB on the top... that should switch to CRZ after your plane hit's T/C but mine remains in CLB forever.

Thanks a lot Matthew, I really appreciate that. I'm not really doing anything different when programming the CDU before flight. When I use X-Plane 10's FlightFactor 777, it doesn't give me problems. the CDU will automatically switch from CLB to CRZ after it reacher T/C. But I'm not sure why it's not doing this in PMDG's 777.

 

I've looked at page 83 of the introduction manual and couldn't find anything related to this.

 

 

I'm referring to the status display in the EICAS... where it says CLB on the top... that should switch to CRZ after your plane hit's T/C but mine remains in CLB forever.

Yes, the thrust limiting carrots on the EICAS displays are an airline option.

You can set that through the CDU in the display options which is under the aircraft section.

 

It's there because if for whatever reason you got a huge wind shift that killed your performance while in cruise, if you have the option for a CRZ setting, then I would assume that the A/T will max out thrust at the CRZ setting. However, if you like the CLB setting, you will have more available thrust to use in the aforementioned wind shift example.

 

If you are flying at higher altitudes for your given weight in cruise and you're also flying slow to save fuel or for whatever other reasons you choose, you may not have enough thrust in CRZ limit mode to get your speed back. That would force you to have to descend to get your speed back.

 

Like I said, that's what makes sense. I don't exactly know how if the A/T would truly be limited with the CRZ limit or if there's an override within the A/T logic.

Share this post


Link to post
Share on other sites

All the settings and options in the sections PMDG setup and FS options are not part of the real CDU but the way PMDG allows user to set up aircraft configurations. The option between thrust limit CRZ/CLB in cruise is not accessible to pilots in real life if I'm not wrong.

However, even if your aircraft is configured with CRZ thrust limit in cruise, then you still have the option to "override" temporary that limit by selecting a higher thrust limit by pressing the INIT REF then select INDEX > THRUST LIM which is accessible to pilots in flight.

Share this post


Link to post
Share on other sites

That was it, thanks so much guys. Which mode would you recommend though? Leaving it set to CLB or CRZ?

 

When would you pick one or the other? Seems like setting it to CRZ would be better, since it will auto switch to CRZ mode once you hit T/C. Can't really see a reason to leave it at CLB, wouldn't that waste a lot of fuel?

Share this post


Link to post
Share on other sites

All the settings and options in the sections PMDG setup and FS options are not part of the real CDU but the way PMDG allows user to set up aircraft configurations. The option between thrust limit CRZ/CLB in cruise is not accessible to pilots in real life if I'm not wrong.

However, even if your aircraft is configured with CRZ thrust limit in cruise, then you still have the option to "override" temporary that limit by selecting a higher thrust limit by pressing the INIT REF then select INDEX > THRUST LIM which is accessible to pilots in flight.

  

That was it, thanks so much guys. Which mode would you recommend though? Leaving it set to CLB or CRZ?

 

When would you pick one or the other? Seems like setting it to CRZ would be better, since it will auto switch to CRZ mode once you hit T/C. Can't really see a reason to leave it at CLB, wouldn't that waste a lot of fuel?

I totally forgot about manually selecting the thrust limits within the CDU.

 

Good call!

 

As for why you would want it; I'm sure it goes back to what I said before about flying high and slow and having the thrust immediately available to you. As for fuel consumption, it wouldn't change a thing. Remember, it's only a limit. When in cruise, the A/T will maintain the same thrust setting needed for the VNAV speed regardless of what LIMIT is shown on the EICAS.

Share this post


Link to post
Share on other sites

I think that in most situations it would make no difference as I have rarely seen the thrust going up to the CRZ thrust limit in cruise (except during step climb of course).
I know that it is mainly a company's choice so it depends on the airline (the livery) you fly for (it is part of the configurations of the liveries).

So I would say it is up to you. Now I"m not commercial pilot, so I cannot give a professional advise.

Share this post


Link to post
Share on other sites

I think that in most situations it would make no difference as I have rarely seen the thrust going up to the CRZ thrust limit in cruise (except during step climb of course).

I know that it is mainly a company's choice so it depends on the airline (the livery) you fly for (it is part of the configurations of the liveries).

So I would say it is up to you. Now I"m not commercial pilot, so I cannot give a professional advise.

I agree with you.

 

I don't fly the 777 either, however in the CRJ 200, since we don't have auto throttles, it makes sense for us to manually change the thrust carrots. However they are only advisory.

 

I honestly don't see the point in why there is an option for an airplane with auto throttles. Maybe someone can enlighten us.

Share this post


Link to post
Share on other sites

The manuals for this type of airplane are huge and it's something that could take quite some time.

Huge? The Introduction Manual is 175 pages.

Share this post


Link to post
Share on other sites

Huge? The Introduction Manual is 175 pages.

systems manuals? Those are pretty big. Yes, the intro manual isn't too large.

 

However, I was referring to the fact that if the OP had other questions, that he can still come over here and ask questions. Whether he read the manuals or not. Especially if he had a systems question. The manuals for those are huge and as I said before, not everyone has hours on hand to give themselves a type rating.

  • Upvote 1

Share this post


Link to post
Share on other sites

 

 


The manuals for those are huge and as I said before, not everyone has hours on hand to give themselves a type rating.

 

This should be taken with caution. The PMDG products are quite complex addons, not just start and fly GA aircraft. Hence it requires a minimum in terms of reading the manuals and learning.

 

There are tons of questions on this forum that are answered by the introduction manuals or FCOMs.

And I'm not talking about reading every single page of both FCOMs + FCTM + Introduction manuals + tutorials: all these manuals are PDF and it allows for easy search with key words it usually takes only a couple of minutes to find most of the answers using the search engine.

 

I'm not saying that is specifically the case of the OP here nor do I want to point anyone in particular but there are too many people that come to the forum expecting to be answered without having to do any search themselves but others to do for them.

 

So welcome to come ask questions? Yes, definitely, but it doesn't prevent to spend some time to try to find the answer by oneself.

Share this post


Link to post
Share on other sites

This should be taken with caution. The PMDG products are quite complex addons, not just start and fly GA aircraft. Hence it requires a minimum in terms of reading the manuals and learning.

 

There are tons of questions on this forum that are answered by the introduction manuals or FCOMs.

And I'm not talking about reading every single page of both FCOMs + FCTM + Introduction manuals + tutorials: all these manuals are PDF and it allows for easy search with key words it usually takes only a couple of minutes to find most of the answers using the search engine.

 

I'm not saying that is specifically the case of the OP here nor do I want to point anyone in particular but there are too many people that come to the forum expecting to be answered without having to do any search themselves but others to do for them.

 

So welcome to come ask questions? Yes, definitely, but it doesn't prevent to spend some time to try to find the answer by oneself.

I agree with you. I really do. On all counts.

 

However, because many simmers will be new to this type of high fidelity add on, going through a systems manual will be a daunting task. Many simmers will probably miss the answer even though it's right in front of them because they don't yet have prior understanding of basic systems to decipher what the manuals are telling them about the complex systems of a 777. These manuals aren't just a read and magically understand kind of thing.

 

That's my point. We don't exactly know if someone has or hasn't read up and studied the airplane before asking questions on here. We shouldn't assume someone either has hasn't read the manuals.

 

Some questions have easy answers that can be easily found in the manuals like the one posed in this thread. Some questions dont.

 

For some people, this may be their first time learning about an airplane like this. It may be their first time ever learning about basic turbine systems. Telling someone to just go read the manuals isn't going to net them much help.

 

It is sometimes an annoyance for others to answer simple questions. However, it provides a teaching opportunity for others.

 

You pointed the OP in the right direction and that's what needs to be done.

 

What also needs to be done is to help people understand what they are reading in those manuals.

 

To sum up my point, we are here to help others enjoy this airplane. We have to answer questions at times that we find annoying or unwarranted. We can't just tell people to read the manuals when we don't want answer a question. Besides, if we took the time to type "go read the manuals." We can take the time to answer a question.

  • Upvote 1

Share this post


Link to post
Share on other sites

 

 


For some people, this may be their first time learning about an airplane like this. It may be their first time ever learning about basic turbine systems. Telling someone to just go read the manuals isn't going to net them much help.

 

I agree, that's why I rarely send the poster to a manual without giving the reference. Unless it is blatant the answer doesn't require a specific knowledge but just open the manual and blatant the poster won't make any effort to get the answer that doesn't need any explanation by themselves.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this