777 tutorial question

  • Some of the CDU features are not yet available but will be soon.

    May I ask if this is real soon (meaning it will come as a separate 777-specific update which is being worked on right now and will be released in a few days or weeks or so) or IPACS soon (meaning it will come in the next big AFS2 update somewhere in the future)? Just curious. I like this plane (I've been doing longer flights than I've ever done before in AFS!) and can't wait to also use the CDU!

  • cordial greetings

    I loved the arrival of the wonderful Boeing 777 but I would like to count on your help, because the trim command does not work ... I have already configured it normally, but just as in the A320 the trim does not work, looking outside the 777 we can see the stabilizer horizontal up and down, but the aircraft does not change its attitude, it remains with the same attitude, that is, there is no aerodynamic reaction in flight ... can anyone help?

    Thank you!

    • Official Post

    The pitch trim in the B777 changes the fly by wire trim reference speed in flight and not the pitch trim.

    When you are on the ground it affects the pitch trim directly but in the air you're only commanding the fly by wire to be trimmed for a different airspeed.


    Do this: Fly the speed that you want with elevator commands. Use the pitch trim to alleviate any forces that you need to hold on the yoke.

    Now the aircraft is trimmed for the current speed. If you reduce the thrust it will pitch down, if you increase it it will pitch up to stay the the trimmed airspeed.

  • Another question! I figured out why my 777 doesn't descent at the T/D. The tutorial says this:


    "When the aircraft is flying in VNAV PTH (vertical navigation path) as shown on the PFD (primary flight display) in the top right corner, then the autopilot will automatically descent at the calculated top of descent point."


    However, my 777 flies in VNAV SPD during cruise. Don't know why, I didn't touch a thing. So... how can I switch to VNAV PTH...? As it is now I always (and simply) press the ALT button but the plane should be able to start the descent on its own!

    • Official Post

    I found a bug today that was related to that. The top of descent was calculated on a different glide ratio than the descent profile, that should be fixed with one of the next updates.


    But it should still climb to the cruise altitude and then go into VNAV PATH. It only goes into VNAV SPD when you climb or when you descent too late. But when it's maintaining the cruise altitude even after the top of descent it should be in VNAV ALT or ALT, never in VNAV SPD.

  • I found a bug today that was related to that. The top of descent was calculated on a different glide ratio than the descent profile, that should be fixed with one of the next updates.


    But it should still climb to the cruise altitude and then go into VNAV PATH. It only goes into VNAV SPD when you climb or when you descent too late. But when it's maintaining the cruise altitude even after the top of descent it should be in VNAV ALT or ALT, never in VNAV SPD.

    Ah, okay... Good to know! I noticed during my last flight I didn't reach the set cruise alt (FL410), it kept flying at around FL398, so that must be why I was stuck in VNAV SPD...! The question is why the plane didn't (or doesn't) climb to the set altitude... Maybe this is caused by the bug you mention?


    By pressing a few of the AP buttons (rather at random) I managed to switch to VNAV ALT before reaching the T/D but that didn't make a difference (which is correct as far as descending concerns, so I learned now).


    I remember also, during another flight, changing the cruise alt to a lower one after take off but apparently the system still expects the initial cruise alt and won't switch to VNAV PATH.


    Anyway, I now know where to look for (PATH, SPD and ALT) and what to expect when so I'll see how this knowledge helps during my next flight!

  • Here I am at cruise alt: VNAV ALT is shown, how do I get it to show VNAV PATH...? The T/D is still ahead.



    EDIT
    While I am at it: I notice the sim always uses a certain calculated cruising altitude to calculate the T/D. I set a cruise alt of FL360 at the gate but at the T/D the deviation bar shows I am 5000 ft underneath the desired alt... which means the sim thinks I wanted to fly FL410 and is calculating the T/D based on that and not on my desired and set cruising alt.


    Two questions:

    1. can I somehow set a cruising alt in the sim (I know I can do that in the plane but I mean in the sim itself, so it actually calculates things using my set alt)?

    2. if not, how can I figure out or see what cruising alt the sim has calculated and is expecting and is using for its calculations (apart from putting it on a runway before putting it at a gate)?


    EDIT 2

    Passed the actual T/D and no descent... Again, I know how to solve this but would like the automatic descent at T/D to work. ;)


    • Official Post

    The route uses the cruising altitude of FL410 unless the route is too short for that. The exact cruising altitude is set when you position the aircraft on the runway ready for takeoff.

    Only when you level off at that pre-programmed cruising altitude will the autopilot switch to VNAV PTH. Otherwise it's just leveling at an altitude that is not the cruise altitude in which case it uses VNAV ALT.

    The T/D also uses that cruise altitude from the route if I remember correctly. If you fly higher than the pre-determines altitude for example it still caps at that FL410.


    At the moment it's not possible to change the cruise altitude at all. This will probably change in a future update.

    With the recent changes I made you can at least see the cruise altitude you're supposed to fly.

  • Okay, got it! That explains it all indeed. I also chose a lower cruising alt because the 777 sometimes can't reach the 777, either because the T/D is there before I am at FL410 or the plane simply stops climbing. But well, now I at least know why I get VNAV ALT and how to get VNAV PATH. The next time I will position myself at the runway to see the cruising alt the sim expects and only then will I position myself at the gate. That's a trick that should work to figure out the desired cruising alt. Let's hope my 777 has the power to actually reach it. ;)


    Looking forward to your recent changes and of course the future option to change the alt! ;)

  • You may have to select a different thrust limit for now. Per default it displays "THRUST LIM" in the lower right corner of the CDU, go to that page and then bump the thrust limit from CLB 1 to CLB. This is also going to be fixed next update... :)

    Thanks for the tip!


    BTW I positioned myself at the runway of Liverpool for a short hop to Heathrow: set alt was 6000. When I reached the T/D the deviation bar showed I was around 17000 ft (or so) below the calculated path... Odd... So the alt set on the runway was wrong anyway...? Well, hopefully the upcoming updates will fix all this.

  • And now it worked! Flew from EGPE to EGNM, taking a route that was 256.5 nm long. Positioned myself at the runway, cruise alt was automatically set to FL380, which made sense. And with the CLB setting I went up to that alt like a rocket! :) After around 15 minutes and around 85 nm I was at FL380 and... VNAV PATH appeared on the PFD! :)


    Also tried a flight to FL410 and the plane reached it without a problem, although VS dropped to around 400 in the end so the last bit took a while. ;) Anyway, this CLB settings helps a lot!


    With the recent changes I made you can at least see the cruise altitude you're supposed to fly.

    Can't wait for it!


    EDIT
    BTW As it is now I set the speedbrake at 1/3 when I start the descent and leave it there until approach: this keeps me close to the profile all the way. It works better then setting the brake to full up and down all the time. ;)