CRJ200 and its "14th stage bleed air".

[Bostar 7]

Hi

I'm not sure if this subforum is the best for this kind of question, so, if admin consider, please move it to another one more suitable for it.

My doubt is about the 14th stage bleed air of CRJ 200. I know most of the CRJ200 in the market don't simulate this system, but I'm curious about how to handle it.

As far as I've discovered, this system supplies high pressure, from the engine compressors 14th stage, to other systems like anti-ice, cowl anti-ice and reversers and it seems operative mostly of the time. But, I haven't found when it is necessary to turn it on (or turn it off): Before the take off (for the reversers in case of reject the takeoff)? Maybe at the acceleration altitude (1000ft)?

All the checklists I've found online don't mention anything about this system. Some addons in the market simulate the low pressure system (the 10th stage) but there are several versions about how to manage it. Some start it directly in the platform, others recommend to use the internal APU until the acceleration altitude and there, start it. But nothing about the high pressure system.

I'll appreciate any clarification about this point.

Best regard

[Mace 1,909]

I assume you have already visited the Aerosoft CRJ subforum?   There are some real-world CRJ (700/900) pilots on there, and even though I don't recall any -200 pilots there, the -700/900 people may have some knowledge of this system and exactly how it works with respect to the checklist/flows.

[Chock 17,769]

Here you go. Manual for the real thing explaining the pneumatic systems. This is only 18 pages long, so  not a long read and you should be good to go in ten minutes:

http://www.smartcockpit.com/docs/Bombardier_CRJ_00-Pneumatic.pdf

Edited June 22, 2020 by Chock

[ahsmatt7 1,199]

You always arm (turn on/push in the switch) the 14th Steve bleed air switches. Always turn them on when powering up the airplane. They stay on the entire time until cold and dark. You don't touch them after that unless you are doing something with the QRH or an anti ice test on the ground to ensure that the 14th stage valves are actually working properly.

If you don't turn these switches on, you won't have any reversers or anti ice.

 

I'm a check airman for all the CRJ variants.

Edited June 22, 2020 by ahsmatt7

[ahsmatt7 1,199]

1 hour ago, Mace said:

I assume you have already visited the Aerosoft CRJ subforum?   There are some real-world CRJ (700/900) pilots on there, and even though I don't recall any -200 pilots there, the -700/900 people may have some knowledge of this system and exactly how it works with respect to the checklist/flows.

The bleed system is different on the 7 and 9 compared to the 2. You are right, if some of those forums users fly the 200 then they should be able to add some knowledge to the original poster.

[JRBarrett 3,070]

18 minutes ago, ahsmatt7 said:

You always arm (turn on/push in the switch) the 14th Steve bleed air switches. Always turn them on when powering up the airplane. They stay on the entire time until cold and dark. You don't touch them after that unless you are doing something with the QRH or an anti ice test on the ground to ensure that the 14th stage valves are actually working properly.

If you don't turn these switches on, you won't have any reversers or anti ice.

 

I'm a check airman for all the CRJ variants.

Our company operates 3 CRJ-200s. Our SOP is the same. The 14th stage bleed switches are left pushed in at all times.

One difference between the 200 and the 700/900 is that on the latter, the reversers are hydraulically actuated - they don’t use bleed air.
 

Edited June 22, 2020 by JRBarrett

[busdriver 258]

I'm looking forward to the 787 and it's electric compressors when I make the move to it in January of 2021. One less thing to have to learn. :)

[Bostar 7]

15 hours ago, Chock said:

Here you go. Manual for the real thing explaining the pneumatic systems. This is only 18 pages long, so  not a long read and you should be good to go in ten minutes:

http://www.smartcockpit.com/docs/Bombardier_CRJ_00-Pneumatic.pdf

It was the first website I visited to get information 😉

But, if you check those documents, they only explain the systems but not the procedures. Anyway, very useful for understanding those systems.

16 hours ago, Mace said:

I assume you have already visited the Aerosoft CRJ subforum?   There are some real-world CRJ (700/900) pilots on there, and even though I don't recall any -200 pilots there, the -700/900 people may have some knowledge of this system and exactly how it works with respect to the checklist/flows.

As this is a question related to a non-Aerosoft product, I preferred don't bother the admin of their forum exposing my question there.

14 hours ago, ahsmatt7 said:

You always arm (turn on/push in the switch) the 14th Steve bleed air switches. Always turn them on when powering up the airplane. They stay on the entire time until cold and dark. You don't touch them after that unless you are doing something with the QRH or an anti ice test on the ground to ensure that the 14th stage valves are actually working properly.

If you don't turn these switches on, you won't have any reversers or anti ice.

 

I'm a check airman for all the CRJ variants.

Thank you very much for your input, that was I was looking for. Once I understood the function of this system I suspected that It's mandatory to activate it since the engines run up to obtain the pressure for the reverses and the anti-ice. But it called my attention that several checklists I found online didn't mention it. I appreciate your input.

14 hours ago, JRBarrett said:

Our company operates 3 CRJ-200s. Our SOP is the same. The 14th stage bleed switches are left pushed in at all times.

One difference between the 200 and the 700/900 is that on the latter, the reversers are hydraulically actuated - they don’t use bleed air.
 

Thank you for confirm the info.

I hope it doesn't bother you if I ask another question related to this topic: in your companies, during the takeoff and landing, the APU keeps running using their bleed instead of open the 10th stage? As I said in my first post I've seen different ways for this procedure:

•  APU off + 10th open (using the engines directly)

or

•  APU on + 10th closed until acceleration altitude

... or maybe it's something that depends on the weather/payload?

Best regards

Edited June 23, 2020 by Bostar

[JRBarrett 3,070]

2 hours ago, Bostar said:

It was the first website I visited to get information 😉

But, if you check those documents, they only explain the systems but not the procedures. Anyway, very useful for understanding those systems.

As this is a question related to a non-Aerosoft product, I preferred don't bother the admin of their forum exposing my question there.

Thank you very much for your input, that was I was looking for. Once I understood the function of this system I suspected that It's mandatory to activate it since the engines run up to obtain the pressure for the reverses and the anti-ice. But it called my attention that several checklists I found online didn't mention it. I appreciate your input.

Thank you for confirm the info.

I hope it doesn't bother you if I ask another question related to this topic: in your companies, during the takeoff and landing, the APU keeps running using their bleed instead of open the 10th stage? As I said in my first post I've seen different ways for this procedure:

•  APU off + 10th open (using the engines directly)

or

•  APU on + 10th closed until acceleration altitude

... or maybe it's something that depends on the weather/payload?

Best regards

That is exactly the procedure we use.

On the ground, and during takeoff, the engine 10th stage valves are kept closed, the APU bleed is on, and the isolation valve is open, thus the APU supplies bleed air to both packs during taxi and takeoff. This allows the engine to develop maximum power during takeoff. The variant of the CF-34 engine on the CRJ-200 is quite a bit smaller than that used on the 700 and 900, so relieving the engine of supplying 10th stage bleed during takeoff is helpful.

Once the aircraft is established in climb, with gear and flaps retracted, the pilots transfer the packs to the engine bleeds.

This has to be done in a specific sequence, because you do not want the APU and engine bleed air supplying the duct at the same time. First, the isolation valve is closed, which stops the flow of APU bleed air to the right pack. Then, the right engine 10th stage bleed valve is opened, so the right pack is now being supplied by the right engine. Then, the APU is shut down, and the APU bleed air valve is closed, and finally, the left engine 10th stage bleed valve is opened to supply the left pack. With the isolation valve closed, the left pack is supplied only by the left engine, and the right pack is supplied only by the right engine.

If you were flying as a passenger on a 200, and an astute observer, you would note a slight reduction and then increase in airflow from the cabin vents twice as this transfer of the packs from the APU to the engines is taking place after takeoff.

Prior to landing, the APU is started at some point after the aircraft descends below 10,000 feet. The APU turbine engine is supplied by air from an opening on top of the left side of the fuselage, which has an electrically operated door. The door is normally closed when the APU is shut down, and must be open when the APU is running.

That door cannot be commanded open if the aircraft is flying faster than 320 knots, so APU start on descent is delayed until below 10,000 feet, when the aircraft will be flying 250 knots or slower. Once the APU is running, the packs are transferred back using the reverse of the procedure on takeoff.

First the left engine 10th stage bleed air is closed, then the APU bleed valve is opened. Then, the right engine 10th stage bleed valve is closed, and finally the isolation valve is opened, after which the APU will be supplying both packs.

The reason the 14th stage bleed valves are left open all the time is because that system only supplies anti-ice and reversers. Even though the 14th stage valves are always open, unless anti-ice is being used, there is no load on the engine so having the valves open has no effect on engine performance. In cold weather operations there may be occasions where engine inlet anti-ice is required on the ground after engine start, and of course, the 14th stage valves must be open on takeoff in case of a rejected takeoff, (so that reversers will be immediately available if needed).

On the 700/900, the engines produce quite a bit more power, so this procedure is not normally necessary. Typically the APU will be shut down after engine start. Also, on the 700/900 bleed air management is normally automatic. The isolation and engine bleed valves operate in the proper sequence to transfer the packs from APU to engines without the pilots having to do anything, although it can be done manually if the automatic system is not working for some reason.

Edited June 23, 2020 by JRBarrett

[Bostar 7]

Thank you so much for such a detailed post.

It's a pleasure when the pro's sharing all this info in the forum.

Now, I can complete even farther my procedures and checklists with this all useful information.

Best regards.