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Aircraft will not hold altitude


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I am currently at FL240 with AP, NAV, and ALT all activated. the aircraft constantly climbs and decends even when AP is engaged. Throttles at at max, de-ice is on, recycled spoilers...This started after the last patch, and I have reinstalled the aircraft 3 times...what is going on with this thing?

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Same here!  I just did my first flight in the CRJ after WU#4 and it could not hold cruise altitude at FL300?  AP was engaged while in NAV mode and ALT captured.   Never happened to me before.  I turned off AP and cycled the FD and was able to re-establish level cruise flight. 

I will try again with different flight and see if this happens again.   

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Have you checked the assignments of the axles of your control units?
There are always reports that there have been undesirable changes in the assignments after updates.

 

Fl240 and max speed is absolutely not normal.
If you have installed the SDK, you could switch off the "Visual Icing" under "Options".

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Think it has something to do with weight and balance. You set passenger, cargo and fuel according to SimBrief plan. But SimBrief and Aerosoft uses different weight on passengers so ZFW may be different in flightplan and plane. This may cause  issues with CG and the plane will become unstable in flight. My solution was to set “correct” passenger weight in SimBrief fleet menu for CRJ - think it was 93 kg / 206 lbs if I remember correct - so ZFW is correct in FMC.

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  • 1 month later...

i am having problems climbing over FL300 half the time, it autotrims to full NU and speed decreasing to around 160. i am within the flight envelop and never full pax and load, Max TOW well within limits. 

At one point it just start falling , not stalling . Nose drops and losing altitude. It can climb to around FL 270 without any problems. What are you speed and ROC above FL300 ? ANyone having this problem ?

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10 hours ago, LesOReilly said:

290 to transition to Mach .74?

 

The transition occurs at like 28,700-something feet.  But the best way to know when to do it is just realize that it happens between 28k and 29k feet, and monitor for when 290 kias and m0.74 are the same.  Then you hit the button and should be ok.  If you miss it, you can just hit the button when you notice, and adjust the requested climb speed to m0.74 and you should be good.  Unless you've already gotten behind the power curve, which will involve a pretty radical intentional reduction in altitude until your speed comes back to those levels.

 

Having said that, I have noticed that from time to time (at least pre-patch, not sure if the patch addressed this) to even maintain m0.74 required full power, as CLB was not enough.  And that's with anti-ice off and the APU on, which I've been told gives the engines just a touch more oomph.  Why that is, and whether or not that conforms to reality, is for someone older, smarter, and wiser than me to say.

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3 hours ago, KevyKevTPA said:

 

The transition occurs at like 28,700-something feet.  But the best way to know when to do it is just realize that it happens between 28k and 29k feet, and monitor for when 290 kias and m0.74 are the same.  Then you hit the button and should be ok.  If you miss it, you can just hit the button when you notice, and adjust the requested climb speed to m0.74 and you should be good.  Unless you've already gotten behind the power curve, which will involve a pretty radical intentional reduction in altitude until your speed comes back to those levels.


There appears to be a bug with the transition from IAS to MACH causing the target value to be ~0.03 off.  I do as you suggest, but then increase the target to M0.75 or M0.76 to maintain M0.73-M0.74 in the climb. 

 

 

3 hours ago, KevyKevTPA said:

 

Having said that, I have noticed that from time to time (at least pre-patch, not sure if the patch addressed this) to even maintain m0.74 required full power, as CLB was not enough.  And that's with anti-ice off and the APU on, which I've been told gives the engines just a touch more oomph.  Why that is, and whether or not that conforms to reality, is for someone older, smarter, and wiser than me to say.

 

Using the APU to provide pressurization air to the packs instead of using engine bleed air would indeed provide slightly more thrust.  Someone more familiar with the CRJ systems would have to weigh in on how much bleed air (and therefore engine power) is required for pressurization.  I have not experienced the failure to climb issue yet, unless I leave Wing A/I on by mistake (thus robbing the engines of some power).  The usual explanations for failure to climb are:

  • Letting the speed fall significantly below M0.74 (behind the power curve)
  • Airframe icing (apparently a problem even with icing set to "visual only" in settings)
  • Phantom spoiler deployment (triggered by keybinding / hitting "Esc") that is not visible in the cockpit or externally
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Not sure if this is exactly what we're talking about here, but I did notice on my last flight (with the latest update) that CLB power was not sufficient to maintain desired speed.

 

Nearing my cruise altitude of 36000, I had to apply full TOGA thrust for a bit, because the speed had fallen dramatically, and in a short space of time, to near 160-180kts. Only after applying TOGA for a while did it slowly (very slowly) climb back to about .74/.76

 

I can't tell whether this was down to pilot error (not sure what I would've done wrong then, but ok), or an actual issue somewhere.

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Noticed similiar issue - I need to pick CLIMB sometimes because at FL360 I got 0.720 and going down to 0.7 at cruise altitude on MAN throttle position (almost at CLB). Using Simbrief - TOW 29887 kg.

When I move lever to CLB position though, I accelerate up to 0.760-0.770 and need to go back to manual and it decelerates back to 0.720 or less. 

 

Still like in previous post I cannot tell if it is pilot error but before update I did not have problem to reach stable 0.740-0750 Mach speed. 

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And here, and I quote the more important thing:

 

«In the real jet, in cruise from FL340-FL390 you will need 87-89% N1 and a fuel flow from about 1800GPH-1950GPH to maintain .78.  It is very very sluggish at altitude, especially anything over FL360.  Any small power changes can take 30 seconds to even see much of a change in airspeed. Not responsive at all. And to barber pole it up high would probably take everything it’s got.»

 

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