I have to join the crowd that has no problems with VNAV descents. To say it can't handle the calculations is just not correct. Of course I have screwed up descent profiles, but hindsight usually allows me to spot my mistake and so far they have always been mine! That said, if anyone can detail a situation that I can reproduce where the TOD was incorrect, I will happliy give it a try.

Gents, a suggestion that could help us get a better understanding of the difficulties folks are having. Could someone who is having the problem post the flight plan, aircraft they are using including livery, specific PMDG options selected that are not the default, list of add ons, wx configuration including how external wx programs are being used and as much information about the issue as possible. This could give us all a chance to take a look at specific issues, potentially try the route and provide more specific suggestions.

You know, I wonder is this behavior is related to the known SP1 "Idle Thrust" issue. Remember that when on VNAV PATH, the plane will follow the descent path regardless of your speed, and a higher speed means a higher descent rate.Try using the "G" key to raise your gear when you take off, and see if that makes a difference to your descent.

Ok, you are right. Many times we are asking you for help but without giving enough pistes about the problem. I'll try to give you some pistes as flight plan, way points, altitudes, etc.Altough someone wasn't very kind in his answer, may be he was right, and I need to read more and learning before to ask.I'll do it.If the majority of folks haven't got problems about the plane, could be I didn't read enough.Thanks friends.

Ok, you are right. Many times we are asking you for help but without giving enough pistes about the problem. I'll try to give you some pistes as flight plan, way points, altitudes, etc.Altough someone wasn't very kind in his answer, may be he was right, and I need to read more and learning before to ask.I'll do it.If the majority of folks haven't got problems about the plane, could be I didn't read enough.Thanks friends.

No worries, go ahead and post the details and lets see if we can figure out what's happening.

Well, I just remember, I've done some flights since I bought the game, between EGKK and EHAM following the tutorial wich comes added.So all flights and data were perfect, points, altitudes, CW, Trimer, Fuel, Payload etc..During flying, all data were matching waypoints and altitudes like the PMDG's tutorial. Problem starts just after to pass T/D. From here aircraft doesn't respond as well as tutorial. Low decline etc..as I stated before.I'll try to incorporate some picture about FMC and cockpit, those will spend me some time.Likely I always put my foot in it, so I'd like to know where.Thanks Folks

Well, I just remember, I've done some flights since I bought the game, between EGKK and EHAM following the tutorial wich comes added.So all flights and data were perfect, points, altitudes, CW, Trimer, Fuel, Payload etc..During flying, all data were matching waypoints and altitudes like the PMDG's tutorial. Problem starts just after to pass T/D. From here aircraft doesn't respond as well as tutorial. Low decline etc..as I stated before.I'll try to incorporate some picture about FMC and cockpit, those will spend me some time.Likely I always put my foot in it, so I'd like to know where.Thanks Folks

When you post back please be sure to provide as much detail as possible as suggested in my earlier post.

George, if you manually adjust the speed/alt at diff waypoints way before calculation of TOD, shouldn't the FMC take these into account? I've tried adjusting this so that I'm at approx 2,500ft and 170kts about 10nm out but the FMC can't seem to handle this.

Hi guys, here you are somes pictures what I took during flying between EGKK-EHAM following as the PMDG manual explains.At the beginning I haven't got any problem, climbing is correct getting waypoints and altitudes at time and distance.Problem starts some time after start up T/D when it flies below 10000fts. Always I arrive to EHAM over 4000fts and 240knts.I tried differents ways to manage CDU changing parametres of speed and altitud from AP and AT. But result was the same.Finally I think what worst was solution given by PMDG Support in this post. "Fly with 900"http://forum.avsim.n...hen-descending/Sould I to give up to flying with 800?Thanks a lot friends, you let me sharing my troubles.

Hmmm. Two things I see:1. In the first pic, the airspeed is at F0 maneuvering speed. The jet probably wants to slow, but you have to put the flaps down to slow and more. If a waypoint has a speed restriction that is lower than F0 maneuvering, you need to configure appropriately.2. In the second third picture, that drag required message seems odd as the commanded speed is 240 and you're on speed. Also, you're in VNAV speed and approaching the decel point. You're a little high, but that's not a bug, that could be from several things (ATC, slow to change MCP, etc).So. . . pay attention to the speeds that are on the legs. If fix EH607 wants 196 knots, you'll have to be at Flaps1.Also, what is your idle thrust? It should be around 30%N1. If you have 40%N1, then you have a throttle issue.EDIT: for some reason, I couldn't view all three pics before. I see in pic #2, your N1 is high. Lot's of things going on here. You may need to go back to the tutorials. Good luck!

Picture 2. You are below min flaps speed and even though you are right on top of the airport you still haven't touched your flaps. In that position, you should be at gear down flaps 25 and considering flaps 30. You would probably then be 3,000ft lower and 60 knots slower. The NG is very highly automated, but you are still the pilot and you still have to fly the thing.Not related, but why is your transition altitude so low?Edit: Did you actually read Tabs post when he suggested you try the same thing in a -900? He was very politly telling you that you had a pebcak error.

Finally I think what worst was solution given by PMDG Support in this post. "Fly with 900"http://forum.avsim.n...hen-descending/Sould I to give up to flying with 800?Thanks a lot friends, you let me sharing my troubles.

To be fair, Ryan is saying the 800 is particularly slippery and that there might be less problem descending with the 900. He says the 700 is even less of a problem.The images are helpful but you're problem is caused earlier in the descent. To know why this happened we'd need to see where things began to go wrong, not how they ended up.

Hmmm. Two things I see:1. In the first pic, the airspeed is at F0 maneuvering speed. The jet probably wants to slow, but you have to put the flaps down to slow and more. If a waypoint has a speed restriction that is lower than F0 maneuvering, you need to configure appropriately.2. In the second picture, that drag required message seems odd as the commanded speed is 240 and you're on speed. Also, you're in VNAV speed and approaching the decel point. You're a little high, but that's not a bug, that could be from several things (ATC, slow to change MCP, etc).So. . . pay attention to the speeds that are on the legs. If fix EH607 wants 196 knots, you'll have to be at Flaps1.Also, what is your idle thrust? It should be around 30%N1. If you have 40%N1, then you have a throttle issue.

196 knots at EH607 isn't a restriction, it's a prediction. But you're right, to match that prediction you'd need to start extending flaps, though deceleration is not the problem. The real problem in picture 2 is that the aircraft is 1519 ft above the descent path.Kevin Hall

To be fair, Ryan is saying the 800 is particularly slippery and that there might be less problem descending with the 900. He says the 700 is even less of a problem.The images are helpful but you're problem is caused earlier in the descent. To know why this happened we'd need to see where things began to go wrong, not how they ended up.196 knots at EH607 isn't a restriction, it's a prediction. But you're right, to match that prediction you'd need to start extending flaps, though deceleration is not the problem. The real problem in picture 2 is that the aircraft is 1519 ft above the descent path.Kevin Hall

I don't think I said it was, but fine: restriction or prediction. There's a whole bunch of problems going on here, but deceleration with N1 of 37% sounds like a problem to me. The 1519ft above is a symptom, so to speak.

I don't think I said it was, but fine: restriction or prediction. There's a whole bunch of problems going on here, but deceleration with N1 of 37% sounds like a problem to me. The 1519ft above is a symptom, so to speak.

"restriction or prediction." Big difference.You are right, there are a bunch of problems but N1 idle at 37% isn't one of them, as that is a pretty normal descent idle and one I often see.In your first pic, I suspect you didn't update your descent forcast to allow for the 18 knot tailwind, did you? That is going to turn into a nasty crosswind landing if you ever make it down there. Look at your pics again, #2 is a tailwind landing and #3 is a 20knot crosswind, but none of them show you managing your flaps correctly.As others have mentioned, this aircraft is slippery, so you can slow down or go down, but it is very hard to slow down and go down. I do not think it is that the plane is too fast, I think it is that you are flying the plane too fast.

Pic 1. Would have to see the previous route segment to make a comment !Pic 2. You did not capture the localizer and have missed the glideslope........you are now too high. APP mode is not armed and at that stage you should be at (at least) flaps 15 with the gear down.Pic 3. Drag Required is normal in this circumstance. The next waypoint is 220 kts and you are near the deceleration point (green circle)The ND also shows that you are not on the path.( think of " drag required " as your best friend during VNAV path descents)My advice is to follow the tutorial guide to the letter !!!Fred.