CRJ 200 climb performance in Summer

[Sawmill]

One question though: What if the CRJ 200 is on a giant treadmill?

 

[regionalcap]

Why do we let an ATC rule over ride aerodynamics? If the airplane needs to climb at 300 fpm why do we let the 500fpm notification rule put us in a position of high drag? ALPA should lobby to get this rule thrown out.

I don't think its a ATC rule that you have to climb at 500 fpm. The rule( As I understand it)is if you can't climb at least 500 fpm, you have to notify ATC. Right GCD?

Why would ALPA want that rule thrown out? It lets ATC know when we are barely climbing so they can plan accordingly. I think it is a good thing.

 

[sweptback]

There really is a reason the FMS displays

UNABLE CRZ ALT

As I understand, all that message means is that your TOC is past your TOD. I don't think it necessarily means that you can't reach your planned altitude, that's what the climb capability charts are for.

 

[Crzipilot]

Its refreshing to hear from someone who actually knows what they are talking about and not just wanting to "hear" themselves.

But the ones that needed to hear it, or read it, couldn't due to the shades on and ipods sticking in their ears..... Oh well...

 

[DGdaPilot]

As I understand, all that message means is that your TOC is past your TOD. I don't think it necessarily means that you can't reach your planned altitude, that's what the climb capability charts are for.

That's not correct...at least not on the -700. If you're too heavy for the altitude you pop in (like FL400 or 410), it'll give that message.

 

[GCD]

Climbing at 250 KIAS to planned cruise altitude is not a good technique, unless it is to a lower FL. Here's why.

FAR Part 25 cruise altitude requiremnts:

At such altitude that the airplane must be able to:

1. Maintain designed cruise speed at maximum cruise thrust;
2. Be able to have a 1.3G buffet margin;
3. Still have climb capability to climb at 300 FPM at max continuous thrust / climb thrust.

If you climb to a higher FL at 250 KIAS and cannot accelerate to designed cruise speed at max cruise thrust, you've screwed yourself out of that altitude. The only way you can get to cruise speed is to descend.

When you go through the higher FL's, you should be transitioning from KIAS to Mach climb, anyway.

Keeping the deck agle lower for the climb will keep your kenectic energy higher and it will also help your thrust available by keeping the engines at a lower angle. The key word is intake. If the engine's angle is steep, it doesn't have as much intake to produce thrust with.

 

[BoilerUP]

Climbing at 250 KIAS to planned cruise altitude is not a good technique, unless it is to a lower FL. Here's why.

FAR Part 25 cruise altitude requiremnts:

At such altitude that the airplane must be able to:

1. Maintain designed cruise speed at maximum cruise thrust;
2. Be able to have a 1.3G buffet margin;
3. Still have climb capability to climb at 300 FPM at max continuous thrust / climb thrust.

If you climb to a higher FL at 250 KIAS and cannot accelerate to designed cruise speed at max cruise thrust, you've screwed yourself out of that altitude. The only way you can get to cruise speed is to descend.

When you go through the higher FL's, you should be transitioning from KIAS to Mach climb, anyway.

Keeping the deck agle lower for the climb will keep your kenectic energy higher and it will also help your thrust available by keeping the engines at a lower angle. The key word is intake. If the engine's angle is steep, it doesn't have as much intake to produce thrust with.

I thought it was illegal for people to post honest-to-God informative posts on Flightinfo these days.

Nice work and thanks!

 

[GCD]

I always try to help or mentor others because I sure needed it, and got it. It's time for me to pay back.

 

[flynryan15]

One question though: What if the CRJ 200 is on a giant treadmill?

You sir are evil!!! But funny

 

[Poahi]

GCD,

Thanks. You've confirmed my suspicion.

 

[djsk]

And then when you speed up N1 goes down because the fans have so much drag. Airplanes climb thanks to excess thrust. The CRJ has no excess thrust. Its a miracle they certified the damn thing

 

[DrewBlows]

That's not correct...at least not on the -700. If you're too heavy for the altitude you pop in (like FL400 or 410), it'll give that message.

That is correct, with a caveat, you must enter the actual temperature (ISA+) in the performance page in order for the FMS to calculate the max altitude properly. At my company we aren't supposed to use the FMS performance data anyway, but it's good to know the airplane thinks it will make it.

 

[DGdaPilot]

That is correct, with a caveat, you must enter the actual temperature (ISA+) in the performance page in order for the FMS to calculate the max altitude properly. At my company we aren't supposed to use the FMS performance data anyway, but it's good to know the airplane thinks it will make it.

You're right. Eagle doesn't let us use it either. I agree that it's a nice little backup to our thought process, though.

 

[GCD]

DJSK,

That is not why the N1 goes down when you accelerate. Think it through a little bit.

 

[Russ]

GCD

Have regularly climbed the -200 at 250/.7?
I have as that's my companies profile. I find I have the ability to climb to filed altitudes with a comfortable buffer. Perhaps my point of contention is with the term of higher flight level. If the -200 won't make it to a particularly high altitude at one speed, it likely won't or shouldn't be at attempted at any other. When however it's operated within it's proper (not it's certified) envelope, 250 to .7 provides a much better climb rate than 290 to .7 and provides more than an adequate level of safety.