Hi, I don't have the problem. I use Active Sky Advanced. The Overspeed warning comes up at .861 Jan-Paul

1) Not an issue organic to MD-11--I've had the same overspeed with Level D in several recent flights (FL370/M.85 etc)2) Will not be an issue if you deselect winds aloft on AS6.5 options setting--for many, not a realistic fix--but it singles out AS as the culprit3) More likely to appear in winter months when jetstream is howling and temperatures are extremely cold4) Occurs when a station is reporting radically different windspeed than current--AS team should be able to explain inputs/outputs to wind model5) Hand entering cruise winds via MCDU does not seem to significantly alter the equation6) Seems to occur with very strong head/tail component--then that component dramatically falls/raises--power setting cannot react in timeRecommendation: PMDG Dev Team work with Active Sky Dev Team and develop a patch that establishes a set of wind rate of change do not exceed values/criteria--if a delta between current cruise winds exceeds x degrees/second than that will be discounted and the model will default to an averaging methodology. I'm not a programmer, but if you can translate the above into 0s and 1s--that would be awesome :( Thanks for a superb product.Col (ret) Rich Perry, USAF

Just to piggy back on the Rich's answer, I use FSUIPC to dampen wx shifts for both FS9 & FSX. I set the smoothing to 1 deg/kt change per 8 seconds and also turn off turbulence and smooth the pressure/temp values to half the default rate provided by FSUIPC. I like the HiFiSim products but so far they still don't seem to get into the MSFS internals and force it to settle down.

Hi, I don't have the problem. I use Active Sky Advanced. The Overspeed warning comes up at .861 Jan-Paul

Jan-Paul,You don't have the problem yet and it's also not related to any WX simulation used.Try to lower your total fuel on board via the PMDG Option Menu to a total of 12000 kgs.Then see what happens under the same conditions as in your screenshot.Why this happens? (Kelly already mentioned it in this thread)Tanks 1&3 have two compartments. The most outboard compartments, refered to as WingTipFuelTank are kept full as long as possible to have an Mmo of .87When this WingTipFuel is transfering into the inner compartments (starting around 14000Kgs total fuel and below) Vmo/Mmo are decreasing.Refer to: FCOM Limitations page L00.6 and page L00.9Systems manual, Fuel System, page Fuel 10.10, Gravity and Jet Pump Transfer.Problem in the simulation is that Mmo is coming down below the real limit of M.85/320.Hope the development team will correct this, or maybe some beta tester is able to put it on their list.Regards,Harry

Recommendation: PMDG Dev Team work with Active Sky Dev Team and develop a patch that establishes a set of wind rate of change do not exceed values/criteria--if a delta between current cruise winds exceeds x degrees/second than that will be discounted and the model will default to an averaging methodology. I'm not a programmer, but if you can translate the above into 0s and 1s--that would be awesome :(

You mean the PFD is influenced by cross- and headwinds and decreases the red line to M0.82?

Jan-Paul,You don't have the problem yet and it's also not related to any WX simulation used.Try to lower your total fuel on board via the PMDG Option Menu to a total of 12000 kgs.Then see what happens under the same conditions as in your screenshot.Why this happens? (Kelly already mentioned it in this thread)Tanks 1&3 have two compartments. The most outboard compartments, refered to as WingTipFuelTank are kept full as long as possible to have an Mmo of .87When this WingTipFuel is transfering into the inner compartments (starting around 14000Kgs total fuel and below) Vmo/Mmo are decreasing.Refer to: FCOM Limitations page L00.6 and page L00.9Systems manual, Fuel System, page Fuel 10.10, Gravity and Jet Pump Transfer.Problem in the simulation is that Mmo is coming down below the real limit of M.85/320.Hope the development team will correct this, or maybe some beta tester is able to put it on their list.Regards,Harry

Hi Harry, I have lowered the fuel to empty 6.800 kgs. The Speedtape comes down a little bit, but not below M0.85 where the Overspeed starts. Jan-Paul

Here are some screen shots for consideration...Please let me know if I am interpreting incorrectly.Image #1 - Crusing at FL310 with lots of fuel. Note where overspeed and protection is at. (Noted the first amber number, M0.861)Image #2 - Same spot with only 21K lbs. of fuel. I assume this is after the outboard to inboard transfer. Note overspeed and protection here. Much lower! It would not be possible to cruise at calculated M0.835 here!These tests wre conducted with no external weather. Please see the temps and wind on the MCDU.This shows me that the Mmo is dropping to well below M0.85. Whether this is the aircraft simulation, or the way that FS9 is calculating I do not know. But it is clearly happening.Open to all comments!EDIT: One more question while we're all chatting...what is the storage capacity of outboard and inboard sections of tanks 1&3?Thanks,

Development team and others reading this thread.[[Problem in the simulation is that Mmo is coming down below the real limit of M.85/320.]][[Hope the development team will correct this, or maybe some beta tester is able to put it on their list.]]Quoting myself here, puts total shame on me.Based on the first screenshot in this topic I thought the indication being wrong.Checking both version FS9 and FSX more intense, show the MaxSpeedTape indicating fully correct.My apologies,Harry

Hi, Harry, you are right, now I was able to reproduce the problem, it depends on the total weight of the aircraft. When you select 2/3 Pax load, the problem doesn't occour at low fuel loads. When you select 1/3 Pax the problem appears (Mmo is coming down below the real limit of M.85/320). So it must have something to do with the weight calculation. I don't have the time now to figure out the critical GW. I will try it tomorrow. Jan-Paul

Hi, Harry, you are right, now I was able to reproduce the problem, it depends on the total weight of the aircraft. When you select 2/3 Pax load, the problem doesn't occour at low fuel loads. When you select 1/3 Pax the problem appears (Mmo is coming down below the real limit of M.85/320). So it must have something to do with the weight calculation. I don't have the time now to figure out the critical GW. I will try it tomorrow. Jan-Paul

Jan-Paul,Thanks for this "possible new evidence". Will do some more testing as well.Harry

Here are some screen shots for consideration...Please let me know if I am interpreting incorrectly.Image #1 - Crusing at FL310 with lots of fuel. Note where overspeed and protection is at. (Noted the first amber number, M0.861)Image #2 - Same spot with only 21K lbs. of fuel. I assume this is after the outboard to inboard transfer. Note overspeed and protection here. Much lower! It would not be possible to cruise at calculated M0.835 here!These tests wre conducted with no external weather. Please see the temps and wind on the MCDU.This shows me that the Mmo is dropping to well below M0.85. Whether this is the aircraft simulation, or the way that FS9 is calculating I do not know. But it is clearly happening.Open to all comments!EDIT: One more question while we're all chatting...what is the storage capacity of outboard and inboard sections of tanks 1&3?Thanks,

Kelly,Image #1: Is a correct indication, being it FL300.Image #2: This is not a valid scenario to show Mmo is indicating too low. (If we need to show that.....??)Below FL 310, Vmo 320 IAS is the limiting parameter. Above FL310, Mmo .85 becomes limiting.Nevertheless thanks for your screenshot inputs and please keep them comming if there might be something wrong here afterall.This based on what Jan-Paul just reported.TipTankFuel capacity is around 5500lbs / 2495 kg depending specific gravity.Regards,Harry

Nevertheless thanks for your screenshot inputs and please keep them comming if there might be something wrong here afterall.This based on what Jan-Paul just reported.TipTankFuel capacity is around 5500lbs / 2495 kg depending specific gravity.

Thanks for the feedback and observation on my FL300 goof. :( Flew some more and had similar results at FL370. Will try to get some shots together tomorrow. Until this gets figured out, I guess I can start carrying extra fuel to ensure that the tanks never get below a certain level. Thankfully we don't have to pay for it in MSFS!

So, has anyone ever come up with any conclusions about this problem? It seems we're on our own since the MD was a low seller, thus we're stuck with speed bugs, fuel freeze rate bugs, typos, and thrust problems. Kinda irritating. This will be the last product I buy, I'm sorry to say.

So this is normal? 32,600 to 32,500 LBS of fuel dropped the Vmo (Mmo) from 356 to 331, give or take. This was without any 3rd party weather add ons and no weather themes or real weather from MS engine, all standard atmosphere, no wind. It's extremely disappointing that we can't get a fix for these problems, or even an answer from the team about their existence.

I haven't flown the PMDG MD-11 in a while, but even a cursory glance at the LIMITATIONS section of the FCOM (Page L.00.9) shows that, at some altitudes, there's an approximate 40kt reduction in Vmo as tip tank fuel is reduced below 90% capacity. At other places in the envelope, it's less than that. For instance, at 27,000ft (as in your screenshot), the difference appears to be approximately 25kt.Without looking through the FCOM and determining all the fuel capacities and doing the math, I can't confirm that 32,500lb FOB is the appropriate break point or not. But if you're simply questioning whether it's appropriate to have such a large and instantaneous reduction in Vmo then, yes, it's correct.