CRJ System Question

[Airboss]

Here is a question I am wondering about.

The CRJ's computer figures out a 'maximim' rated power setting on Takeoff, Climb and Cruise.

Why does it drop down a percent or so when you turn on the anti-climb..oops i mean anti-ice.?

i.e Cruise 90.8 with Wing and Cowl off
Cruise 89.8 with Wing off and Cowl on?

Any ideas?

 

[airlinepilot]

Anti Ice

Basically you are taking (been a couple of years but I think it's correct) 14th stage air off the engine to de-ice the wings and Cowls. That is less air you have to cool the engine therefore the FMC computes a lower thrust setting..

 

[Ted Striker]

Here is a question I am wondering about.

The CRJ's computer figures out a 'maximim' rated power setting on Takeoff, Climb and Cruise.

Why does it drop down a percent or so when you turn on the anti-climb..oops i mean anti-ice.?

i.e Cruise 90.8 with Wing and Cowl off
Cruise 89.8 with Wing off and Cowl on?

Any ideas?

I believe it has to do with the bleed causing the ITT to rise, that's why it has you back it off a bit, to keep it within the ITT range. Turn the wings on and you have to come back even further. If you don't, notice the ITT climb.

 

[Ted Striker]

too slow!

Dang, airlinepilot. You beat me too it!

 

[bolete]

Bleed air extraction

Bleed air extraction increases the operating temps of the engine. After selecting wing or cowl anti ice on, you need to reduce %N1 in order not to overtemp your engine. You should be able to watch an itt rise as you open either 10th or 14th stage bleed air valves. You certainly see it on the apu egt when you load it with the packs.

 

[Airboss]

Thanks

Thanks for the quick response.
It's amazing how I can ask people in ops or on a flight and nobody knows, but ask here and you get an answer in 15 minutes.

 

[Ted Striker]

Thanks for the quick response.
It's amazing how I can ask people in ops or on a flight and nobody knows, but ask here and you get an answer in 15 minutes.

Not only amazing, but sad. These people are operating the airplane and have no idea why they do what they do? Beauty.

 

[lamppost]

Why does it drop down a percent or so when you turn on the ANTI-CLIMB..oops i mean anti-ice.?

I think of the "anti-climb" button as the whole airplane!