CRJ slows down on cruise

[TOBS]

Hi Javier, Philipp,

I had a new issue - while on cruise at FL360 / 380 the CRJ starts to slow down nearly to stall speed. I try to speed up but it does not work - I have to go to a lower speed level.

Watch the pic - N1 and N2 are red cause I try to speed up before stall!

Regards Tom

[eaglewing7]

Let me be clear that I do not own the CRJ, so this is just speculative.

Could you have run into icing conditions?  If so, your PITOT and Static ports are likely frozen over, which can result in bizarre behaviour like this.

Were you overloaded for your cruising altitude?  Aircraft, while certified to fly at a service ceiling, cannot be expected to fly there if loaded.  The Falcon 7X, for example, is certified to a service ceiling of FL510, or 51,000 feet.  It cannot, however, even get to that altitude when loaded to the brim with over 5000 gallons of JetA and an additional cargo or passenger weight...

Just some thoughts.  It would be good to tell us what the aircraft weight was, and what the weather conditions were.

[flyinhawaiian]

I think you'll find you're reaching your service ceiling for the aircraft for the given set of circumstances.  You're probably too heavy and it's too hot for you to even consider reaching FL410.  If you look at most real-world CRJ flight plans don't go much higher than FL310.  While the aircraft can theoretically go higher than where you're trying to get to, the Atmospheric and aircraft conditions have to be perfect for it to happen.  Looks correctly modeled to me!  

[woweezowee]

yes, looks like overweight for this altitude

[dpny]

If the CRJ is heavily laden, I will cruise at FL330, and only climb higher if fuel burns off. You will find the same thing if you attempt to climb too high in the ERJ-140.

[Dispatch]

Hi Tobs,

it's not a bug, it's a feature. The CRJ2/CL850 is under-powered in relation to it's w&b limits. So, FL350 is totally realistic. Of course, depends on actual TOW you had. You're having 10kLBS of fuel in your screenshot. I expect you to also have some amount of payload in the back. So it's all fine with the CRJ KIAS at that FL. 

Cheers.

[TOBS]

Thnx Guys - it seems that I am not a very good pilot....

Cheers Tom

[dpny]

Reminds me: I've been meaning to bug Javier for some docs as to optimal climb speeds/cruise altitudes, etc. I picked Fl330-360 from my experience with the ERJ.

[Japo32]

There is a real accident of a delivery (only two pilots on board) and because they were bored they wanted to test how high the plane could fly. Because they were not heavy they could reach FL 400. But the engines stop.

I was testing the plane and it can reach the 41000feet. But not heavy at all.

Your "problem" as said by others is plane configuration.

[TOBS]

Javier,

are you able to provide cruise level charts for the CRJ? I looked on the net but could not find it.

Cheers Tom

[Japo32]

Hi... when I have a little of time free I will search for this. Too Busy with Teo and Laminar lately.....

[thiengo]

Man,

http://forums.jetcareers.com/technical-talk/107924-crj-200-climb-speed-envelope-slow-cruise.html

take a look in your TAT for FL... (2°C each 1000fts at 36000, should lose 72°C, the FL temperature should be -57), in your MFD you can see -40°C, 17 degrees abouve ISA Temp... very hot.... so... it is necessary maintain an appropriate FL.

In the product manual, there is a performance chart to climb.... with the necessary corrections to the atmosphere isa and taking in consideration your gross weight.

hugs...

[TOBS]

Thnx Thiengo,

the climb was not the problem cause I adjust the climb always never above 300 never below 260. What you see is the pic trying to raise the speed shortly before stall. As you are a prof. do you have cruise chats for this bird?

Regards Tom

[thiengo]

I have some documents but no performance charts, only systems and flight patterns.

In the Jrollon's material has a  performance charts for cruise climb rate, corrected for temperature errors in altimeter.

Should consider that at the time of your picture the atmosphere was very hot, others talked about the formation of ice in your pitot tube and static ports, all very relevant.

I am lokking for documents, but in Brazil, i dont meet nobody that fly this aircraft.

i keep lokking...

[X-elbert]

with 5,000 actual hours in the CRJ, I only took it to FL410 ONE Time, I was very light 36000 pounds, and it was an extremely slow climb. Our company had very strict procedures on Climb Speeds and Power settings, to keep crews out of trouble.

[thiengo]

?

with 5,000 actual hours in the CRJ, I only took it to FL410 ONE Time, I was very light 36000 pounds, and it was an extremely slow climb. Our company had very strict procedures on Climb Speeds and Power settings, to keep crews out of trouble.

Exactly, other pilots said this in forums. A bad dog... to climb.

X-elbert, confirm to me, Above FL200 is to climb with 290 IAS at 500fpm?

Recomended.

Is This the performance maintaing 85%N1? approximately

[X-elbert]

500 FPM was the minimum rate of climb, if you could not keep that, you had to level off.

The Max power setting was determined by a table.

The 85% N1 was the lowest power setting for Takeoff using Reduced Thrust.

I don't remember what the N1 climbing to FL 410 was, but I do remember we were right at it, and it more likely was Max ITT

[thiengo]

TOBS,

take a look...

Elbert,

Thanks for your helping and all improvement to my skills. I expect be helped  the TOBS with his doubt

Hugs.

[TOBS]

Thnx for the chart!!

Cheers Tom