CL-604 flex

[balaton]

Dear Pro's,

1. Could anyone please explain why the CL604 doesn't have a flex/reduced/derated takeoff possibility?

2. The CL604's CF34-3B engines has a normal takeoff (APR not activated) ITT limit of 884 C for the last 3 min out of 5 per the AFM. However, the max cont (MCT) ITT limit is 900 C. So, the MCT is ITT is higher than the T/O ?? Any explanation to this phenomena?

3. Do you transfer routinely to APU bleed for every landing? Or only when hot & high?

Appreciate your inputs.

balaton

[Mad (Flt) Scientist]

1. Could anyone please explain why the CL604 doesn't have a flex/reduced/derated takeoff possibility?

Because no-one has asked for it. It exists on the CRJ-100/200, so there's no technical reason I'm aware of that would prevent it. I'm sure someone would quote you a price if you inquired.

2. The CL604's CF34-3B engines has a normal takeoff (APR not activated) ITT limit of 884 C for the last 3 min out of 5 per the AFM. However, the max cont (MCT) ITT limit is 900 C. So, the MCT is ITT is higher than the T/O ?? Any explanation to this phenomena?

I believe the answer is in your own question - those are the APR off ITT limits, and with APR on the limits are 928C for two minutes then 900C for 3 minutes. Since you don't know when APR will kick in, your APR armed but off ITT has to have margin for the APR to work in.

If you check the N1/N2 limits you'll see those tell a similar story - MCT N1 is 98.6%, while Normal Takeoff is 96.2% - but Max Takoff (i.e. with APR) is 98.6%, the same as MCT.

[galaxy flyer]

3. Do you transfer routinely to APU bleed for every landing? Or only when hot & high?

Since MfS did not answer question 3, I'll try to answer it. At our operation, we normally do NOT start the APU for landing unless anti-ice is ON for the landing. Hot & High, at any weight under maximum landing would not require APU for performance reasons, but might be useful for passenger comfort. But, I've never seen it as necessary even in India.

We do use runway analysis by APG for T/O and Landing.

With regards to flex, available on the GLEX, but certified flex power on the CL604 will require money down, I suspect.

I don't work in Le Belle Province, but rather close, BTW.

GF

Nice answer MfS, i've wondered the same thing-how MCT is greater than TO? I always assumed the flat rating was os great the engine essentially ran at MCT or less all the time.

[balaton]

Many thanks for the great explanations.

balaton