Hi Captains,today i want to demonstrate by flying LSZH - LOWW (and imagine you fly under ATC circumstances) "B*tching Betty" ignoring itself calculated speeds and manuals Speed-constraints in descent.Route: DEGES Z2 XEBIX UN871 BADVI UL725 GAMLIFL330, the AIRAC Cycle is 1009, (it will work with any other cycle as well.) 2/3 Pax and Cargo setup, economy layout, 25 tons of fuelGetyour aircraft on cruiselevel, and contact "Wien Radar" between TULSI and BADVI (if flying without human ATC, contact yourself;-))After entering Austrian Airspace, prepare for descent like seen in my screenshots:ATC advice: "[Callsign], expect ILS 29 in Vienna, cross GAMLI at FL250,  start descent when ready"now readback!:-)further clearance:ATC: [Callsign], cleared GAMLI4W Arrival, expect vectors after BALAD"Screenshot1: the speed and altitude constraints at BARUG which are relevant on ATC adviceonly  (like seen in the charts). You will not be adviced on this flight=> kill the constraints!using "clear" button and adequate LSK. Also close the discontinuitiy between BALAD and CF29. (you will get vectors after BALAD)You are cleared GAMLI4W, that means FL80 over BALAD (=> charts!) So put this altitude constraint in the CDU. [screenshot2]Now have a look at your new profile in flightplan mode [screenshot 3] if you do not edit the speeds the aircraft would decelerate too early by automatism. => EDIT Speed @BARUG. [like seen in screenshot 4]now watch screenshot 5 and check all your speeds on descent path. We are in descent inbound GAMLI meanwhile.And finally watch screenshot 6:B*tching Betty decelerates thrust to 245knots, without any reason! This happens on every flight if you interrupt the primary calculated VNAV path between TOD and BALAD with an manual Altitude constraint at GAMLI (FL250] The aircraft follows the altitude constraints perfectly, but isn't able to hold itself [!] calculated or Speed-constraints  in descent. Without MCP Speed intervention i am not able to prevent this, but why this isn't possible without VNAVspeed? Btw. it does also happen, if i set a further manual speed constraint at LIMRA with 303knots before descent. (of course i would have a screenshot for doubters, too!)Why Betty reduces thrust to 245kn at FL270 on every flight at this route?Any suggestions are welcomeregards

That is odd and I have never seen it before. Though I mostly just interviene with the FCP rather than constantly adjust FMS constraits. Not directly related but have you tried fiddling around with descent policy speeds in the PMDG options if you like your speed during descent (>FL100) faster? Also I got confused intially with your thread because as far as I know B*tching Betty only referred to the GPWS and other callouts and not the whole FMS.

That is odd and I have never seen it before. Though I mostly just interviene with the FCP rather than constantly adjust FMS constraits. Not directly related but have you tried fiddling around with descent policy speeds in the PMDG options if you like your speed during descent (>FL100) faster?  Also I got confused intially with your thread because as far as I know B*tching Betty only referred to the GPWS and other callouts and not the whole FMS.

i fly LSZH-LOWW or LSGG-LOWW at least 2 times a week online at IVAO (the ATC instructions are not based on my own) and tested all options, before i came up with this.  To reply on your question, my MD-11 is setup for economy descents and the 303kn are calculated by FMS. Had the same issue, when flying policy descents with 290knots.As i started flying this heavy the term "B*tching Betty" was for sure limited to GPWS. As the aircraft became more and more "female" in special operating, i started rechristening the whole beauty with the name she deserves!:-)Btw. the asterisk maybe look quite more pretty than the "####" replacement the boardautomatism would set instead of "b*tching" . Of course this must be neccessary, someone could blush! :(

I noticed the step descent into KONT on the ZIGGY arrival the automation will slow her down before starting descent near DAG. Darn I thought! This is really great!! Never saw it as a problem.

Hello Paul.If I understand you correctly, you require faster descents than the FMC is providing you, with the inputted flightplan?  So I would:1. Use the FCP and command a speed, altitude and rate of descent as appropriate and as directed by ATC.2. In your screenshot, Gamli to Barug, FL250-12678, in 4 minutes! I surmise thats why the FMC is commanding 245kts? (-3080 fpm @ 245 gives about 16 miles.3 LSZH to LOWW, at FL330? I would select a  lower cruise. Its 320 miles or so, maybe a bit high at 330?4. Enter the speed in the FCP and press FMS SPD, this should input that speed selection into the FMC plan.5. Hand fly the route, manual throttle and stick.............. Regards,David Harrison.

Hi David,thx for you reply. No, i don't require faster descents than FMC is providing me. The 303knots are calculated economy descents by FMS. I've reentered it to demonstrate that it will occur in each case, regardless if you don't overrule the calculated speed of 303kn or manually set speed constrainst. And that shouldn't happen, i hope you'll all agree.If you have an eye once more on screenshot 6, you'll see that the deceleration occurs between LIMRA and GAMLI [at ~FL270] and not between GAMLI and BARUG.  Even in this case there isn't any problem to fly the route as calculated. After the issue i normally change to commanded speed at same value as calculated [=303kn]. I only want to show that this issue doesn't depend on wrong user interaction, this is most problably a programming logical error, and  this flight is an invitation to all costumers and developers to experience it. :-)Btw. the flightlevel on this route isn't unusual, and it's also flown in real and a short cruising level is more economic than flying  lower but longer in cruise.regards

This is really great!! Never saw it as a problem.

i know 2 alpha stage airbus aircrafts out there, which would make you really satisfied. :-))

I only want to show that this issue doesn't depend on wrong user interaction, this is most problably a programming logical error, and  this flight is an invitation to all costumers and developers to experience it. :-)Btw. the flightlevel on this route isn't unusual, and it's also flown in real and a short cruising level is more economic than flying  lower but longer in cruise.regardsknow 2 alpha stage airbus aircrafts out there, which would make you really satisfied. :-))

PaulG,Takes a couple of days before I can run your scenario.As you mentioned '303knt', like to know the LandingWeight and CostIndex used for this flight.(######ing at Betty: She has become my girlfriend, because she tells me I might be doing something wrong.)(######ing the MD11: If you fly her at least twice a week on this route, I think you love ######es)Regards,HarryNow I see what you mean by '*' and '####'.Let's get constructive, not #####-hing

Hi Paul, yes I see what you mean! However;So "Betty" or whatever "gremlin" was at work in your FMC, didn't appear for me? I will watch for it in future flights though.This sim is one very complex piece of kit.........I think there are many variables that are at work, ( weights, weather) some perhaps, we are unaware of at the conscious level?I am still marvelling at the "features" built into the aircraft! The protection envellopes are a challenge in themselves! Cheers.David Harrison

David,Thanks for being constructive.Regards,Harry

Hi Paul, yes I see what you mean!  However;I have just flown LSGG to LOWW, with the MD11F ( I usually fly cargo).  I saw 290 kts descent  ( I fly policy)  both in the FMC plan and commanded all the way down to BALAD at 8000'.  I did not see the magenta "245 Thust" in the PFD?  So "Betty" or whatever "gremlin" was at work in your FMC, didn't appear for me?  I will watch for it in future flights though.David Harrison

Hi David,thx for your help reproducing it. Pls make sure to set the the altitude constraint at GAMLI FL250. That is essential. If i don't do this, the decelerating will not happen for me, too. I tested it only with PAX machines, but that shouldn't make any difference i think. It is not neccesary from where you start. I can see it on every flight, which has this descent route. I did the descent programming enroute and even before start to investigate if there is any difference.  There isn't anyone:-) It also happened in policy descents [290kn] for me. But meanwile i have changed to economy descents.cheers

PaulG,Takes a couple of days before I can run your scenario.As you mentioned '303knt', like to know the LandingWeight and CostIndex used for this flight.(######ing at Betty: She has become my girlfriend, because she tells me I might be doing something wrong.)(######ing the MD11: If you fly her at least twice a week on this route, I think you love ######es)Regards,HarryNow I see what you mean by '*' and '####'.Let's get constructive, not #####-hing

Hi Harry,cost index was 80, fuel from LSZH = 25tons. and the weights you get from loadmanager (in my initial post i have written: 2/3 Pax/Cargo, setup economy layout)the landing weights depend from where you start. (LSGG/LSZH.) the essential part of the flightplan is: "UL725 GAMLI" the GAMLI4W arrival and not to forget preparing descent as in my initial posting:a) clearing both constraints at BARUG (cause not adviced by ATC):( Altitude at GAMLI FL250 in CDU   (following by 1. manual input in FCP altitude bug) => further clearance for GAMLI4W you get while descending inbound GAMLIc) BALAD at FL80 in CDUd) 8000 in FCP after clearance for GAMLI4WThe input sequence in CDU doesn't matter, you can prepare it on ground at departure airport, i have tested for that, too.enjoy your ride, with the ######;-)))cheers

Paul,  My answer is: Looking at the Navigraph chart for STAR GAMLI4W, BARUG is always 250kts at FL180. Now the Airac in my MD11 always has BARUG at 250 /-18000.  The Navigraph speed addendums state " If not otherwise instructed by ATC, cross the points BARUG, GIGOR,NIGSI with 250kt or cruising speed if lower".      So to solve this "quirk" I ask ATC for a DIR TO BALAD ( or better still a direct routing, which they do during off peak hours!).On a different topic have you tried a night landing in Rain, with cloud and vis down to 1/2 mile at LOWW?...............  Ya know, that "Go Around" button really works!!!!! Cheers.David Harrison

Hi David,hope you enjoyed your ride :biggrin:your charts are correct, so are mine, buta) no speed limit by ATC in this situation so overrule it (i pointed on this in screenshot1):( the deceleration occurs before GAMLI (that is far before BARUG, too)and don't forget to purchase the LOWW v2 Flytampa scenery :(  before your next go around in Vienna. :wink:cheers

Hi Harry,cost index was 80, fuel from LSZH = 25tons. and the weights you get from loadmanager (in my initial post i have written: 2/3 Pax/Cargo, setup economy layout)the landing weights depend from where you start. (LSGG/LSZH.) the essential part of the flightplan is: "UL725 GAMLI" the GAMLI4W arrival and not to forget preparing descent as in my initial posting:a) clearing both constraints at BARUG (cause not adviced by ATC):( Altitude at GAMLI FL250 in CDU   (following by 1. manual input in FCP altitude bug) => further clearance for GAMLI4W you get while descending inbound GAMLIc) BALAD at FL80 in CDUd) 8000 in FCP after clearance for GAMLI4WThe input sequence in CDU doesn't matter, you can prepare it on ground at departure airport, i have tested for that, too.enjoy your ride, with the ######;-)))cheers

Hi Paul,Maybe you solved it already, but as promissed;Have flown your suggested scenario and have an answer to your question.To understand why things happen here as they do, please keep this in mind:- For the approach transition from BALAD to the CF29, you planned a direct track, expecting radar vectors.- The limitation at BARUG (250/18000 OR BELOW) was removed. (but only ATC may cancel this)- ATC wants you at FL250 over GAMLI.The normal profile, calculated by the FMS and based on your routing/restrictions above, will give the following predicted crossing altitudes:GAMLI FL 266, BARUG FL197, WW450, FL182, BALAD FL103.So, GAMLI at FL250 would require a descent just before the calculated profile descent.BUT.......Here is where things get more complicated.Entering a fixed crossing altitude at BALAD / 8000 (don't understand why you fix it at 8000, more about this later) will trigger a recalculation of the profile.The recalculated FL at GAMLI will become something like FL234, while fixed already at FL250.Now to your initial question:\\Why ???? reduces thrust to 245kn at FL270 on every flight at this route?\\Because crossing GAMLI FL250 will bring you above the profile for the rest of the routing.To get you into a better (or name it Betty kinetics) position over GAMLI in order to regain the profile, a speed reduction is performed. (simular to a DECEL* prompt when passing the TOD during cruise)Renaming her to the Betty of your choice for this is not my style. Also it does no right to the developers that simulate this plane as real as they can get.Some final remarks and questions, as you fly this stretch regurarly;As David mentioned in his reply, the BARUG restriction (250/-----180) can only be lifted by ATC. Not being familiar with IVAO, this BARUG restriction and GAMLI FL250 can not be made in normal profile mode.Why do you insert a fixed crossing altitude of 8000 over BALAD? It is as essential to the profile as entering FL250 GAMLI as you state above.Not using Navigraph charts here, the Austian AIP instead, but don't expect a difference, shows a crossing altitude /++++8000 for BALAD when selecting the approach transition. The charts mention to expect radar vectors to final when downwind abeam 10-15 miles.BUT... Even when planning a radar vectored (direct) approach to runway 29, as you programmed the FMS, the 30 plus track miles remaining from BALAD do not require a crossing AT 8000.It was my pleasure to fly some short stretches into LOWW, also with a different arrival iso NERDU we handled a couple of month ago.Also it does not have to do with textures or how real the aircraft looks from the outside, but addresses her inner system behavior or handling.Hope it helps you 'piloting' this plane on the next stretches.Regards,Harry

Hi Paul,Maybe you solved it already, but as promissed;Have flown your suggested scenario and have an answer to your question.To understand why things happen here as they do, please keep this in mind:- For the approach transition from BALAD to the CF29, you planned a direct track, expecting radar vectors.- The limitation at BARUG (250/18000 OR BELOW) was removed. (but only ATC may cancel this)- ATC wants you at FL250 over GAMLI.The normal profile, calculated by the FMS and based on your routing/restrictions above,  will give the following predicted crossing altitudes:GAMLI FL 266, BARUG FL197, WW450, FL182, BALAD FL103.So, GAMLI at FL250 would require a descent just before the calculated profile descent.BUT.......Here is where things get more complicated.Entering a fixed crossing altitude at BALAD / 8000 (don't understand why you fix it at 8000, more about this later) will trigger a recalculation of the profile.The recalculated FL at GAMLI will become something like FL234, while fixed already at FL250.Now to your initial question:\\Why ???? reduces thrust to 245kn at FL270 on every flight at this route?\\Because crossing GAMLI FL250 will bring you above the profile for the rest of the routing.To get you into a better (or name it Betty kinetics) position over GAMLI in order to regain the profile, a speed reduction is performed. (simular to a DECEL* prompt when passing the TOD during cruise)Renaming her to the Betty of your choice for this is not my style. Also it does no right to the developers that simulate this plane as real as they can get.Some final remarks and questions, as you fly this stretch regurarly;As David mentioned in his reply, the BARUG restriction (250/-----180) can only be lifted by ATC. Not being familiar with IVAO, this BARUG restriction and GAMLI FL250 can not be made in normal profile mode.Why do you insert a fixed crossing altitude of 8000 over BALAD? It is as essential to the profile as entering FL250 GAMLI as you state above.Not using Navigraph charts here, the Austian AIP instead, but don't expect a difference, shows a crossing altitude /++++8000 for BALAD when selecting the approach transition. The charts mention to expect radar vectors to final when downwind abeam 10-15 miles.BUT...  Even when planning a radar vectored (direct) approach to runway 29, as you programmed the FMS, the 30 plus track miles remaining from BALAD do not require a crossing AT 8000.It was my pleasure to fly some short stretches into LOWW, also with a different arrival iso NERDU we handled a couple of month ago.Also it does not have to do with textures or how real the aircraft looks from the outside, but addresses her inner system behavior or handling.Hope it helps you 'piloting' this plane on the next stretches.Regards,Harry

Hi Harry,thx for your idea on that, but it doesn't really explain whats happening.it wasn't the first existing "disfigurement" on the MD-11 and it is of course not the last. So there is no need to to search for excuses naming that "Betty kinetics" (but it sounds nice:-)). This aircraft in real is able to fly an "interrupted" NAV without difficulties.The PMDG  747 flies this leg without this behaviour, too. And don't forget the shown thing includes two strange behaviours:a ) speed deceleration without any need ( if you overrule via MCP accurately timed with the pre-calculated speeds, it does its further job precise as it should) so what call it else then a logical error in the systems?b ) thrust deceleration though  "human" CDU overrule with the calculated FMC Speeds set to prevent "a)"and each of them, neither a ) or b ) should happen, hope you'll agree.And it isn't any excuse to scrutinize the ATC advices. (BALAD FL80, GAMLI 250, killing the constraint over BARUG) always expect the unexpected when flying under human ATC circumstances. In the tutorial and advanced tutorial you will not get this aircraft to it's edges.after 1400 hours flying the MD-11 i know this aircraft pretty well.  And if posts like these don't get ignored, behaviours like that hopefully will not appear in future aircrafts (maybe there is a final SP for the MD-11 too, who knows). Though this nutpicking the MD-11 is for sure the best released airliner for FSX at the time. No doubt. Sometimes i am bored with "normal" flying, in this case bug-hunting is something challenging.  :Pe.g, you can find a bug in the 747 CDU blocking the scratchpad totally, or you can crash [pmdg gauge.dll]   the FSX  with "special" CDU inputs in the MD-11 and j41. But everything at the proper time.cheers