tango4

Sorry for the delay, I was a bit busy. I just submitted a support ticket. If I have an official answer I'll post it here.

Hi Claus, and thanks for your help. Unfortunately, that is not how the B777 is designed.There is no ADIRU1 and 2. The architecture you are referring to is basically that of older airplanes like the B744 (3 Air data systems, each connected to an Air data computer). On the B777, ADIRU feeds both PFDs when everything is OK, and will isolate a source if it is deemed wrong. If ADIRU fails, then SAARU will take over. Stanby instruments are only fed by SAARU on non ISFD equipped aircraft. But you are right, you see different results with the other failures. Hi again Dan, and thanks for your time. First I asked a B777 pilot on another forum (PSX). He told that he never had this failure in real life or in simulator training but that he basically expected to see some data. This is not hard proof but made me want to ask here. The only data I have is the Boeing FCOM. It says: "Air Data / Attitude (AIR DATA/ATT) Source switch Off-normal position (ALTN not visible, switch out): *the ADIRU provides air data and attitude information to the PFD and ND *Alternate sources or the SAARU are automatically selected to replace ADIRU air data or attitude, as required. ALTN-non normal position (ALTN visible, switch in). The PFD and ND alternate air data/attitude source is selected as follows: *air data (captain): SAARU single channel *air data (first officer): ADIRU single channel *attitude (captain and first officer): SAARU" It does not explain what this failure should do in case you leave those switches in normal position (the automatic reconfiguration algorithm is not explained) BUT it does state that if I push the switch on the captain's side, Air data comes from SAARU single channel. So I don't see why a failure called "ADIRU air data invalid" would prevent air data from being displayed, at least on the captain's side. Do you think with those references I can send them a ticket ?

Thanks for your input, Dan. In that case do you think it would be appropriate to submit a ticket to PMDG for such an issue in order to get their official statement ? I'm asking you because you are a beta tester, so you might be familiar with their procedures. I don't want to be a pain in the...well, somewhere ! Thanks again.

Thanks for the help. I do agree with you, this is clearly an unreliable airspeed situation. Nevertheless, I still find it strange that with AIR DATA/ATT switches in alternate there is no data. I expected wrong data, possibly on all 3 systems, but at least some data. After reading the FCOM I had the FEELING (I insist on this word because I might be wrong) that the purpose of that very switch was basically to force "Raw data" on PFDs to allow the pilot a possibility to decide if one is valid or not. (Otherwise, the aircraft is deciding on itself). Any further input appreciated ! All the best.

Hi everyone, There is something I can't figure out regarding this failure. When I trigger it, here is what happens: AP and AT disconnect. That part seems logic of course. But I loose Air data on both PFD (Capt and FO),while ISFD is still displaying Air Data. The way I understood the FCOM, both PFD should display some data, although they should disagree. I have the NAV AIR DATA SYS EICAS message, and the associated checklist says (First page, second item): "Crosscheck airspeed and altitude on the PFDs and standby flight instruments for accuracy. Each display is receiving data from an independent source." This is exactly the way I understood the FCOM. Now, let's assume this is due to the automatic behavior of the ADIRU. When I push the AIR DATA/ATT switches to ALTN on both PFD's, it is clearly stated that each PFD becomes single channel sourced (One from ADIRU, the other from SAARU), and that I should be able to see some readings on both, although different. Could someone tell me if this is a bug of if I'm missing something here ? All the best !

Thanks guys, that clearly makes sense now ! All the best. Charles

Here is my source: (FMC 737 Bulfer guide) https://www.dropbox.com/s/gxnnoqmo7mpjuya/bulfer.jpg?dl=0 (the first 3 paragraphs). As you can read in my message, I AM expecting differences in those FMS. It's just this one does not make sense to ME and I wanted to know if someone could explain it. As mentioned in this document GP is defined in the database, so I don't understand why it would show up differently in those 2 FMS. I already thought about IAN but this involves non ILS approaches, and the example I mentioned is an ILS. And as I understand it IAN is the WAY of performing the approach which is different from VNAV (the "standard" way). But IAN needs accurate data also, so that still doesn't make sense to me. Charles

HI everyone, I have a question regarding the way the FMC displays a GP indication in the legs page between 2 waypoints in a database approach. The understanding I have is that normally, VNAV computes an IDLE descent path between 2 waypoints, and if not possible, then it will respect the contraints (ALT and SPD). All that is true, EXCEPT when in approach mode, where it has to follow a published GP. The way I understood things, the decision to have a GP 3.00° for example between 2 waypoints comes from the database, and not the FMC, because it means the procedure has been designed as such. According to some readings, I expected to see a GP in the legs page even for an ILS approach (although of course you won't fly it in VNAV), which is clearly not the case, at least not everywhere. I used the example of LFPG ILS26R in the screenshots below, using the latest NAVDATAPRO cycle (I had basically the the same results with an older Navigraph cycle). I initially thought that the "issue" came from the database itself, but the curious thing is that it is not displayed in the same way in the B737 and the B777 ! Here are two screenshots of the same procedure, of course with the same common database, in the B737 and the B777: https://www.dropbox.com/s/evikvadq9yid97b/2015-09-29_00001.jpg?dl=0 https://www.dropbox.com/s/cpd21eubwt4vnky/2015-09-29_00004.jpg?dl=0 In the first case, there is no Glide, and in the second case, yes (between PGS532 and RW26R). Can anyone explain this ? I know these two FMS are not from the same manufacturer, but from what I read, I did not expect to see any difference here. Best regards everyone.

Thanks a lot for your clarifications Ryan. If you have time to check it, could you confirm that I did not miss anything significant (pilotwise I mean !) that is not simulated in the NGX ? And if possible could you confirm the A/T issue on single engine is a bug ? Best regards. Charles

Thanks for your kind reply. Actually, my frustration comes from two points: 1) Some items were simulated in previous PMDG products. Emergency release gear handles were simulated in the MD11 if I remember correctly. So I expected them to be in the NGX. I AM NOT SAYING IT IS A BIG DEAL , just saying that I spent some time looking for a click spot that did not exist. Much easier if it was clearly written in the tuorial. 2)In former documentations, the rule of thumb was, if it is not mentioned, it is not simulated, basically. The problem is that now we have the FCOM, and it is hard to find those little things being left out. In the 777 intro document, there is a very interesting part mentioning "things you would not otherwise notice". I just think it would have been great to get a short list of items not simulated. And once again, this is not a feature request list. I too would like better rollout sound, rain effects and so on but this is not my point with this post. I'll try to add it to the list but I can't edit my first post and I don't understand why... Trying to figure that out. Thanks for all your replies. Well at least here is the updated list. If I manage to do it I will update my first post. But it seems I did not miss many things. UPDATED LIST: -Weather Radar -EFB -Emergency gear release handles -FMC: *Engine out VNAV guidance *RTA (Required Time of Arrival) *ISA Dev in descent forecast (possible to enter but not taken into account in descent profile calculations) *ARINC 424 routing *EOSID -Autoflight: A/T impossible to re engage after engine failure (Bug ??) -Maintenance pages of the FMC -Circuit breakers

I know !!! The point of my request is not getting an overview of the systems. It is avoiding spending hours figuring something out which I think is simulated while it is in fact not simulated. I did not mention the circuit breakers in my first post initially because I would count this as obvious (as Wx radar and EFB). I only added it to try and make a COMPLETE list of what is not simulated. And I am not complaining about anything here !!! I know breakers are not used by a flight crew on day to day operations. But I really spent time trying to understand the behaviour of Engine out VNAV and I was thinking that I was missing something. While the thing I was missing was that it is not simulated and it was not written anywhere that I know of. So please everyone stop telling me that we'll get a weather radar and not an efb. I am aware of that and it is not the point of my post. I just want to know if there are other functions of the plane not simulated that I might find in the FCOM or QRH. Cheers.

Just to clarify the intent of my post, this is not meant to be a WISHLIST, but a list of what is not simulated in order to avoid confusion. I'll try to update the list at the bottom of my first post according to replies.

First PMDG please accept my apologies for multiple posts, I kept having an error in my navigator, and thought my post wasn't online. If an admin could delete the other posts below that would be great (really sorry !!) ISA Dev appears and can be entered but I read somewhere that it is not taken into account for descent calculations. I will check agains for auto thrust, but I'm pretty sure I can't re engage it after engine failure (I'mm talking of the NGX). And I was not talking about engine out SID, but VNAV guidance (having the aircraft accelerate at engine out altitude that you enter in take off ref page 2). Charles

Hi everyone and especially PMDG team. I think everything is in the title. For years, when browsing through a forum, you would see people answer to a newcomer "it's in the manual, go read it !". And that is definitely true. The problem is that from the NGX onwards, realism is now very high, so high that the NGX and 777 are provided with the real FCOM. So here comes my problem, some things are not simulated in those planes, but this is not clearly mentioned in the documentation. Of course, for some items, it is obvious (EFB for example), but for others it is much more hidden. I remember losing several hours wondering why in case fo engine failure at or above V1, the VNAV mode did not provide engine failure guidance although the version of the FMC simulated in the NGX was supposed to. Well, I decided to ask in this forum and guess what, not simulated ! But his is not mentioned in the manuals. So I know this is not the way a company usually advertises, but in this case, I really think it would be helpul if we could have such a list in the documentation, updated according to the various service packs. Here is my list for the NGX (I'm not yet familiar with the 777 to write one on my own). -Weather Radar -EFB -Emergency gear release handles -FMC: *Engine out VNAV guidance *RTA (Required Time of Arrival *ISA Dev in descent forecast -Autoflight: A/T impossible to re engage after engine failure (Bug ??) Am I forgetting things ? Best regards to everyone and huge thanks to the PMDG team for providing us with such quality add ons. UPDATED LIST: -Weather Radar -EFB -Emergency gear release handles -FMC: *Engine out VNAV guidance *RTA (Required Time of Arrival *ISA Dev in descent forecast -Autoflight: A/T impossible to re engage after engine failure (Bug ??) -Maintenance pages of the FMC -Circuit breakers

Got the answer from Ryan himself at PMDG. Here is his answer: We did not model the stuff on page 11.41.2 - this is on the list for additions to the airplane in SP2. Regarding the other stuff however, there is no automatic switching to the ENG OUT modes on the NG's FMC - it's advisory only and you have to manually activate them using the prompts at 6L/6R.