That's a very good point, actually.

James,

 

I haven't had any problems with the PMDG B777.  Everything has been self-induced.  :-)

 

This all reminds me of something I was told long ago about automation and airplanes:

 

 "Automation does not cause Overspeeds - pilots do.  Automation does not miss speed and altitude restrictions, pilots do.  Automation does not make navigational errors, pilots do.  Automation does no have hard landings, pilots do.. "  :-))

 

It's been awhile, but it seems the conversation kinda went downhill from there. :-))

 

Billy Bluestar

Hi, James and everyone,

 

The throttle is in HOLD when the plane starts to nosedive, but the throttle N1 is @ 72%.  This makes no sense to me, as AFAIK, the throttle should go to minimum before going into HOLD.  Also, the pilot is supposed to have the ability in HOLD to slow the descent by manually adjusting the throttle -- increasing it to 72% N1 should SLOW the descent, not cause a nose dive. VNAV should try to correct for the excessive speed by raising the nose.   James, what happens if you use the F1 or F2 key to reduce the throttle to minimum when it stays at 72%?  Finally, also want to note the next waypoint (TON??) is still showing an expected altitude of FL360 after the descent has begun. 

 

It's possible that there is a throttle problem, but I would guess a bad panel state as Walter suggested.  James, do you save your flight at the end and then start your next flight from the previous saved flight by any chance?  This involves reusing and resaving a panel state built on a panel state built on a panel state ... which often leads to a corrupt panel state and strange behavior.

 

Mike

This makes no sense to me, as AFAIK, the throttle should go to minimum before going into HOLD. 

 

Exactly what I thought, but, as you can see, the A/T at the beginning of descent goes into THR, sets around 72% and then straight to HOLD, without going to idle first.

 

 

James, what happens if you use the F1 or F2 key to reduce the throttle to minimum when it stays at 72%?

 

It happens that the idle thrust does not 'sustain' the aircraft and it goes straight into a 10000 fpm dive...

 

 

Finally, also want to note the next waypoint (TON??) is still showing an expected altitude of FL360 after the descent has begun. 

 

Maybe because TONDA is still before T/D, thus the expected altitude is still FL 360 (maybe).

 

 

James, do you save your flight at the end and then start your next flight from the previous saved flight by any chance? 

 

Well, I don't know which other way I could do, reload the flight and then what panel state? I tried to reload the flight and then the panel state related to that flight, but nothing changes. Anyway yesterday I did a whole flight, choosing the 777 as aircraft, the airport and then the "777 SHORT" panel state, but I had the same problem (it was another route).

 

 

Well, I don't know which other way I could do, reload the flight and then what panel state? I tried to reload the flight and then the panel state related to that flight, but nothing changes. Anyway yesterday I did a whole flight, choosing the 777 as aircraft, the airport and then the "777 SHORT" panel state, but I had the same problem (it was another route).

 

Hi, James,

 

You could just start a new flight situation each time and have your preferred panel state as your default start-up state.  Mine is one I derived from, if I recall correctly, the C & D, but modified to have ground power connected, battery on, and basic nav lights on.  But it isn't modified and resaved every time I start a new flight.

 

That being said, if you used the "777 Short" state, that should have eliminated the problem -- although it is possible that if you started up where you left off, you loaded a corrupted panel state and that even switching to the stock "777 Short" didn't eliminate whatever was wrong with the panel state you started with.  This is off the top of my head -- if starting w/ a fresh, new situation w/ one of the PMDG-supplied (SP1 or after) panel states, doesn't fix the problem, then seems to me we all need to look more closely at descents begun before TOD.  I think I've done that w/out these issues, but really not sure.

 

Mike

That being said, if you used the "777 Short" state, that should have eliminated the problem -- although it is possible that if you started up where you left off, you loaded a corrupted panel state and that even switching to the stock "777 Short" didn't eliminate whatever was wrong with the panel state you started with.

 

 

I was thinking the same thing. I know it's a long shot, but did you by chance change the default panel state?

 

I had already written about what I think is something not working correctly in the PMDG 777.

 

 

 

You mean this here?

 

http://forum.avsim.net/topic/451182-vnav-descent-behaviour-is-real/

 

 

I take it that since you are now on SP1C...that an uninstall/reinstall of the 777 was performed but did not help?

Yes, exactly, the problem of the dive still remains after SP1c (at least in my case). Please, have a look at the video I made:

 

http://youtu.be/6X8QovoR_gM

 

 

Well, I don't know which other way I could do, reload the flight and then what panel state? I tried to reload the flight and then the panel state related to that flight, but nothing changes. Anyway yesterday I did a whole flight, choosing the 777 as aircraft, the airport and then the "777 SHORT" panel state, but I had the same problem (it was another route).

 

James, I just flew your LIRF-LSGG flight using the .rte file you sent me.  I did not use your saved flight or FMS files on purpose. I started in default case on runway engines running and loaded your route. All I did on the ground was adjust fuel and payload to a reasonable value for the trip TOW 468 klbs.  I notice TOD was about 20 nm after TONDA and predicted crossing at ACOSTA was FL258. I changed that to FL250A.  The only other changes was on the ILS at IAF where navdata loads 250/7000A I changed to 240/7000 just cause I like a hard constraint somewhere in my IAP.  Departure/enroute unremarkable and I executed a DES NOW at TONDA with MCP set to 20000.  Descent across the 250A waypoint normal and down to FL230 where I dialed in 7000 on the MCP. Descent all the way down was very normal.  Very scenic flight.

 

I think you have a problem in your saved panels states somewhere... or perhaps just the saved flight that you restart over Genova.

 

I don't think the problem is your installation, but you can run the installer (as admin) and select REPAIR to make sure. It won't hurt.

Yes, crazy and makes no sence.....it has to be a corrupt installation or panel state.

 

Like I said before, try deleting your FSUIPC.ini.....that has solved all kinds of crazy things for many!

 

And if that does not help.......I suggest you contact PMDG directly for support.

Thank you Dan for doing the whole flight. I tried it at work and it seems to be working as well. Also the problem of the thrust not going into THR when pressing the TOGA switch at go around (see my other thread) is not experienced at work.

 

Rob, I tried without FSUIPC but things don't change.

 

Now, before trying to reinstall, I will try to delete all panel states and all saved flights and start with the ones provided by the default installation.

 

I see in the issue tracking thread set up by Ryan that in SP1 

 

- Fixed VNAV overspeed when DES NOW is used,

 

it means that before SP1 it was an issue. The strange thing is that I bought the 777 after SP1 was out, so I can't have problems of corruption from a previous release.

 

Thank you guys for your help.

 

 

it means that before SP1 it was an issue. The strange thing is that I bought the 777 after SP1 was out, so I can't have problems of corruption from a previous release.

 

There's SP1, SP1b, and SP1c, though, so if you bought it after SP1 but before the others, you might not necessarily be on the latest release, and you might still be subject to previous errors.

 

 

There's SP1, SP1b, and SP1c, though, so if you bought it after SP1 but before the others, you might not necessarily be on the latest release, and you might still be subject to previous errors.

 

I am sure that now I have SP1c, but in fact it could be that I use panel states and saved flights created with SP1 and that are not fully compatible with SP1c. There are anyway 2 "but":

1.: I imported those states and flights into my FS at work and they work correctly

2.: If the overspeed problem has been fixed in SP1, I should not have found it anyway, considering that I have started using the 777 from SP1...

 

 

I am sure that now I have SP1c, but in fact it could be that I use panel states and saved flights created with SP1 and that are not fully compatible with SP1c. There are anyway 2 "but":

1.: I imported those states and flights into my FS at work and they work correctly

2.: If the overspeed problem has been fixed in SP1, I should not have found it anyway, considering that I have started using the 777 from SP1...

 

Panel states from the first SP1 should be OK.  Ryan posted about this somewhere, and as I recall the save dates on the PMDG-supplied panel states did not change after the first SP1. 

 

Only thing I can think of is to take a look at the "modified" dates of the gauge files in FSX/gauges.  I have SP1C.  Looks like there are three:

 

PMDG_777x.dll saved 10/8/14

 

PMDG_777x_2.dll saved 10/8/14

 

PMDG_777x_3.dll saved 9/3/13 (in other words, probably unchanged since original RTM

 

 

Mike

Mike, the first 2 dates are the same, while the one of PMDG_777X_3.dll is 12/14/13, that is more recent than yours. Could this be the problem?