Can‘t climb above FL300

[nettoon 2]

I‘m not sure if I am doing something complete wrong. When I try to climb to FL 380 I fail at aprox FL 300 to continue to climb. Even with airspeed set to M.55 the nose keeps pitching up, but still loosing hight. N1 is at 88. Any ideas?

 

Thanks

[mopperle 4162]

Check this topic:

 

[JRBarrett 675]

9 hours ago, nettoon said:

I‘m not sure if I am doing something complete wrong. When I try to climb to FL 380 I fail at aprox FL 300 to continue to climb. Even with airspeed set to M.55 the nose keeps pitching up, but still loosing hight. N1 is at 88. Any ideas?

 

Thanks

Mach 0.55 is much too slow for 30,000 feet. If the aircraft is not climbing, pulling the nose up higher only makes it slow down. You should be using at least Mach 0.74 as a speed target for climb mode.

 

CLB mode uses pitch to control airspeed. If you use Mach 0.55 as a target, the nose will pitch up much higher than normal to keep the speed down. This puts the aircraft in a very high drag situation. Eventually, it will be unable to climb further, or to accelerate.

 

To recover, you would first need to push the ALT button. This will capture the current altitude, and the nose should come down as the plane levels off. If the power levers are in the climb detent, leave them there. The aircraft should start to accelerate. Rotate the speed knob to set the selected speed to Mach 0.74. When the actual speed reaches Mach 0.74 (lines up with the speed bug on the airspeed indication). Press the SPD button on the autopilot and the aircraft should start climbing again, now holding Mach 0.74.

 

Normally, once gear and flaps are retracted after takeoff, the CRJ should be accelerated to 250 knots for initial climb. Some operators hold 250 knots all the way up to cruise altitude, others increase speed to 290 or even 300 knots once above 10,000 feet. In no case should speed for climb above 10,000 feet be lower than 250 knots. At some point around 30,000 feet, the speed reference will switch from knots to Mach. 0.74 is a good target for climb at higher altitudes, or even Mach 0.76 if the airplane is not too heavy.

 

It is always best to use SPD mode for climb at higher altitudes - NOT vertical speed. VS is fine for descents, but in climb, vertical speed can lead to a stall.

[nettoon 2]

This was obviously not the issue. It seems that the spoilers are extended in an invisible manner. Recycling them, solved the issue. This makes a lot more sense. Since a low speed, should result in a higher climb rate, when in speed mode. 

[JRBarrett 675]

On 3/21/2021 at 10:33 AM, nettoon said:

This was obviously not the issue. It seems that the spoilers are extended in an invisible manner. Recycling them, solved the issue. This makes a lot more sense. Since a low speed, should result in a higher climb rate, when in speed mode. 

“Hidden” spoiler deployment could certainly cause the problem, but lower speed does not automatically equate to higher climb rate - especially in a swept wing aircraft. The CRJ wing, with flaps and slats retracted, is designed to be most efficient at indicated airspeeds of 250 to 300 knots. ThIs is the speed range where lift is maximized and drag is minimized. SPD mode controls speed directly by setting pitch.
 

Above a certain pitch angle, (especially at higher altitudes) lift decreases and drag increases tremendously. This is known as “being on the back side of the power curve”. If the pitch angle is too high, even with maximum engine power, the aircraft would struggle just to maintain level flight, much less climb. You would have an enormous amount of drag, and almost no lift at a high pitch angle.

 

In a CRJ, rate of climb above 25,000 feet would be much higher at Mach 0.74 than at Mach 0.55.

 

Speaking of spoilers - although MSFS does provide a spoiler axis that can be assigned to a hardware lever, I highly recommend not using it with the CRJ at this time. It is best to deploy and retract spoilers using the lever in the VC with the mouse. The hardware axis causes inconsistent results in the sim CRJ - moving it back even a small amount can sometimes cause spoilers to extend fully, and pushing in fully forward will not always fully retract them. Asobo is aware of this problem, but improving the interaction of the hardware spoiler axis may have to wait for further updates to the core sim.

[Chaxterium 119]

On 3/21/2021 at 10:33 AM, nettoon said:

Since a low speed, should result in a higher climb rate, when in speed mode. 

 

Be careful with that thought process. That's true but only to a certain point. Below a certain speed climb performance decreases. Mach 0.55 is way too slow for the CRJ at altitude.

[Vipor51 1]

What solved this for me was to ensure you set elevator trim prior to take off and ensure your anti ice is off. 
 

I have isolated a climb issue to having anti ice on. 
 

Hope this helps you. 

[Bill Beattie 0]

I had a very similar issue on a recent flight, but it happened at CRZ ALT FL390. I notice the speed decreasing, it got down 144 KTS (i forget the Mach) and looked at the trim, it was over 10. Outside view, the plane was pitching up.  I took her off AP, pushed the nose down, trimmed for level flight, but when I re-engage AP, the trim shot up to 13, instantly.  Again, turned off AP, and requested a lower ALT, but I keep fighting trim, and I had to hand fly.  I turned on the EFB to see what the weight/CG was, maybe that was the problem... then the plan leveled on it’s own, without me pushing the nose down.  I re-engaged AP, then set up VS, and it continued on a normal descent.  Not a great experience for the virtual cabin.  

 

I had a similar problem yesterday - but I had left on the anti-ice on,  so I thought it was an engine performance issue - but I remember thinking that the trim was high.  Could this have something to do with the EFB, I’ve read that you need to turn it off before take-off, since you might lose power/engines accidentally.  .  

 

I haven‘t seen this issue before, I started turning off the EFB.

[dihedral 7]

On 3/21/2021 at 10:33 AM, nettoon said:

This was obviously not the issue. It seems that the spoilers are extended in an invisible manner. Recycling them, solved the issue. This makes a lot more sense. Since a low speed, should result in a higher climb rate, when in speed mode. 

Well, that's two of us with the exact same issue and workaround. I've posted frequently in the thread mentioned by @mopperle regarding "phantom spoiler deployment" and my various other hacks to rectify the situ. 

[metzgergva 210]

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