Difficult to slow down

[davierosoft 13]

Yes, it could be the easy way to fix.I'm making a full flight right now with AI on to see if it will create slow down problems.

[nrcrate 40]

I have the idle bug as well- I had 47% N1 on my descent from FL390, and it stayed there until I switched my throttle override setting at FL300. I would not have noticed if it weren't for this thread... Hope this get fixed with an update.

[davierosoft 13]

Strange, I just made the full flight with AI on and I let the FMC know that I was using AI, the initial prt of descend was in SPD mode, and it was unable to be near the path, then, I turned off AI and the throttles came back to idle... This is odd...

[PIC007 82]

This problem isnt specific the the NGX, I have seen it in many other planes, and the reason and fix is simple, get OFF the VNAV when descending. Before everyone jumps all over me let me explain... :-)The FMC does all it's little magic calulations based on a variety of factors, and normally the end result is it computes the TD too late, which requires a steeper descent angle to fly the path, which results in the plane refusing to slow down. The simple fix is to LOWER your descent rate.I use a CI of 80-100 without issue, and normally full fuel. After much experimentation, at around 30-35nm BEFORE the TD, I switch to SPEED mode and set it to 290kts, and then set a initial VS of around 1500fpm, and start down. I adjust the VS descent as needed to keep the 'green banana' on the target fix, and adjust speed as needed at the lower altitudes to cross 10K at 240kts about 20-25nm out, and slow to about about 170kts 5 miles from intercepting the ILS. From that point it's simple to intercept the approach, slow as needed and drop flaps and gear. I aloways intercept around the IAF so I have at least 10nm to configure to land, and have everything hanging out, stabilized and slowed hitting the outer marker.Of course this is for a vectored approach and NOT flying STARS, you milage may vary.

[Spin737 102]

This problem isnt specific the the NGX, I have seen it in many other planes, and the reason and fix is simple, get OFF the VNAV when descending. Before everyone jumps all over me let me explain... :-)The FMC does all it's little magic calulations based on a variety of factors, and normally the end result is it computes the TD too late, which requires a steeper descent angle to fly the path, which results in the plane refusing to slow down. The simple fix is to LOWER your descent rate.I use a CI of 80-100 without issue, and normally full fuel. After much experimentation, at around 30-35nm BEFORE the TD, I switch to SPEED mode and set it to 290kts, and then set a initial VS of around 1500fpm, and start down. I adjust the VS descent as needed to keep the 'green banana' on the target fix, and adjust speed as needed at the lower altitudes to cross 10K at 240kts about 20-25nm out, and slow to about about 170kts 5 miles from intercepting the ILS. From that point it's simple to intercept the approach, slow as needed and drop flaps and gear. I aloways intercept around the IAF so I have at least 10nm to configure to land, and have everything hanging out, stabilized and slowed hitting the outer marker.Of course this is for a vectored approach and NOT flying STARS, you milage may vary.

"Speed Mode," eh? Some people don't like VNAV, but it's hard to use if you're at 45% N1. Do some research on this Speed Mode and see what you find.

[Paul Deemer 13]

The FMC does all it's little magic calulations based on a variety of factors, and normally the end result is it computes the TD too late, which requires a steeper descent angle to fly the path, which results in the plane refusing to slow down. The simple fix is to LOWER your descent rate.

I enter my flight plan and then later in the flight look at the chart and enter restriction altitudes for the STAR and the PMDG NGX, MD-11 and 747-400 always descend with plenty of time to make a gradual unhurried descent. (120 nm to 130 nm out) VNAV works fine every time never have any problems with it. I am starting to suspect Pilot Error or Inexperience for those that can't get this to work right. I'm also using a reasonable Cost Index based on what Airlines use and not some Rocket Number. With Fuel prices being what they are, the idea is to save your airline money is it not?

[davierosoft 13]

It is not logical to refuse to use the VNAV and program the entire flight with the FMC...The most important aid that FMC gives is about the management of the fligt, is how it can well perform its job saving fuel and time (related to wht you need (CI)).Using "speed" is not economical, using speed descend with idle bug is useless, starting an early descent is not so good.If all is programmed correctly, with this addon (without idle bug) or with the other I flown, it is possible to do the full flight with VNAV without any risk to go long or high.FMC calculations are not limited by FSX and who creates the add on will take in mind that the FMC must fly the simulated bird, so, it knows how the plane fly.If you have problem with other add on in vnav I think you must point to the forecast....It is funny that most people think that FMC is the brain of the plane, I was accused sometimes for tests to have not programmed it for visual approaches, or hand flying... but, now we have the opposite situation... We program the entire FMC, let it does all its calculation to use simple flight techniques...I'm not telling tat is wrong using the V/S and SPD, I'm just pointing that there is something strange in programming, and needing the FMC programmed and then disregard its suggestions.

[davierosoft 13]

I did another flight with AI on for almost all the time, also in tis flight, switching off AI worked on idle and it returned to normal values (around 34%).So I tried to do again the descent with TAI on.I added the information on the FMC by telling it tat I want to use AI from crz altitude until 1000ft.I used ASE but I suffered almost all the time of few kts of lateral winds.The descent started correctly in VNAV path this time, it mantained path correctly but speed increased slowly, Drag required started to flash, then remained fixed, and, instead of using the speed brakes I turned off the AI, idle came back to a lower value and the aircraft started to slow, turned AI back on few seconds later and reached the deceleration point, the aircraft started to decelerate at a low rate, also this time it needed my help by turning AI off, then I putted AI on again and turned off permanently at the next decel. point.I can suppose there is something wrong here as the FMC was aware about AI usage and did not managed it correctly.The next test (tomorrow) will be made with clear skies.Need some pilot's feedback on N1 and N2 values.With AI I got something like 41.6-8% of N1 and only 67% of N2As far as I remember with AI on, the idle changes from fligt to approach idle (where N2 must be between 72-79%) and N1 seems to be to high.Strange that when in approach the idle is lower (I've not checked the N2)

[Superpilotv2 2]

I am starting to suspect Pilot Error or Inexperience for those that can't get this to work right.

Hmm, I´m not sure how it is with the others experiencing it but I would call myself somehow educated in FMC terms. I´ve flown dozens of hours with all kinds of boeing FMC´s: PMDG 737 series in FS9 and their 747-400/F and the Level-D 767-300. All three replicate the FMC behaviour very good and I never had a problem like this. On my last NGX flight it all went well, I filled any entry with values, which were based on charts and facts. So I don´t think that I´ve made an mistake which leads to this behaviour. Tomorow I´ll make the same flight from KCLM to KEUG again but this time with clear weather and not my always used FSrealWX weather addon and I´ll fill everything in as I did in the last successful one. If it works well then I know the error was based upon my improper flight planning. If it´ll be the same as the first one, I know that there´s something not right.

[Superpilotv2 2]

I did another flight with AI on for almost all the time, also in tis flight, switching off AI worked on idle and it returned to normal values (around 34%).So I tried to do again the descent with TAI on.I added the information on the FMC by telling it tat I want to use AI from crz altitude until 1000ft.I used ASE but I suffered almost all the time of few kts of lateral winds.The descent started correctly in VNAV path this time, it mantained path correctly but speed increased slowly, Drag required started to flash, then remained fixed, and, instead of using the speed brakes I turned off the AI, idle came back to a lower value and the aircraft started to slow, turned AI back on few seconds later and reached the deceleration point, the aircraft started to decelerate at a low rate, also this time it needed my help by turning AI off, then I putted AI on again and turned off permanently at the next decel. point.I can suppose there is something wrong here as the FMC was aware about AI usage and did not managed it correctly.The next test (tomorrow) will be made with clear skies.Need some pilot's feedback on N1 and N2 values.With AI I got something like 41.6-8% of N1 and only 67% of N2As far as I remember with AI on, the idle changes from fligt to approach idle (where N2 must be between 72-79%) and N1 seems to be to high.Strange that when in approach the idle is lower (I've not checked the N2)

Now I remember: I think I had turned AI on on my approach into PAJN. But back then I wasn´t aware that turning the AI on will raise the idle level, heck I didn´t even know that the idle isn´t static! (Well, i should read a lot more but the manuals are that big and I don´t really like reading them on the screen.) It seems that you suffered from the same I did.

[Paul Deemer 13]

On PAJN LDA X Rwy 08 approach I have speed Intervention set at 175 kts and flaps 15 on the final approach then Gear Down and speed set to VREF +5 +Half the wind. Usually end up with a speed averaging 150-153 kts at Flaps 30.

[PIC007 82]

I'm also using a reasonable Cost Index based on what Airlines use and not some Rocket Number. With Fuel prices being what they are, the idea is to save your airline money is it not?

CI was invented by some pencil pushing bean counter in the back office to save money, I'm not buying the fuel, I'm moving souls...."I'm givin her all she's got Captain!" :-)

[Paul Deemer 13]

...."I'm givin her all she's got Captain!" :-)

That explains alot.

[Thunderbird8 1]

I've had the problem without ever using AI

[davierosoft 13]

I've had the problem without ever using AI

Yes, the bug is not related to the AI and wen I had in HF4 I'm almost sure I never used the AI as the ice is not simulated.