CRJ Engine Questions

FrontierFan

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I am writing a paper and I was curious if anyone with CRJ time could answer a couple of quick questions. I could probably find most answers on the net but I thought it would be better to ask the pros who fly the line.



1) Does your model of the CF-34 have a FADEC?



2) Does the engine have any type of variable controlled stator vanes?



3) How does the pilot flying regulate power requests (power up to a detent, up to a desired N1 or EPR, or combination) on takeoff, climb, cruise, and continuous?



4) Are there any main differences between CF-34 models for all the different aircraft they power (A-10, CRJ-100, 700, ERJ-170 etc. ) besides size and thrust output



Thanks in advance.



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oldskoolbronco2

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1) CF-34's in the 700/900 have FADEC



2) Does the engine have any type of variable controlled stator vanes? yes




3) 700/900 has toga and climb detents, 200 is set by N1% with OAT input in the FMS



4) Are there any main differences between CF-34 models for all the different aircraft they power (A-10, CRJ-100, 700, ERJ-170 etc. ) besides size and thrust output many you have to look at all the individual manuals
 

labbats

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RJP

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FrontierFan[font=Times New Roman said:
4) Are there any main differences between CF-34 models for all the different aircraft they power (A-10, CRJ-100, 700, ERJ-170 etc. ) besides size and thrust output[/font]


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The main difference is that the motors on the Hog produce nearly no thrust.
 

FrontierFan

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Thanks Guys,


Not to bring up old topics, but..

I am trying to determine if the Pinnicle Flt 3701' engines were equiped with a FADEC and if they were not, than could the compressor stall prevention provided by FADEC have helped in preventing the accident.

Any of your thoughts would be helpful.

Thanks

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Regional4life

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Your question was - "I am trying to determine if the Pinnicle Flt 3701' engines were equiped with a FADEC and if they were not, than could the compressor stall prevention provided by FADEC have helped in preventing the accident."


I'll be the first to admit that I am not a CRJ driver, so please, anyone feel free to correct me. To answer your question, it would have depended upon all of the functions of the FADEC controller. Meaning, a compressor stall is a "build-up of air" in the compressor with no where to go until it is forced out of the engine (either the forward portion or aft or both). If the FADEC has an "air reducing" Or "air venting" control function on it, then the answer is potentially yes. However, the CRJ's engines have variable stator vanes that are supposed to solve the problems of a missing FADEC with regards to airflow into and out of the engines, thus eliminating the need for FADEC.

What happened with the CRJ engines in the accident, (granted still not completely determined), appears to be a core lock. What happens with that is airflow decreases into the engine, the internal temperature increase in the core, (in this case, only one engine actually overtemped) causing some of the components of the engine to expand and "lock up". The engines N1's were moving, but the crew had no N2. The only way to be able to relight is to have plenty of airspeed and the core to have cooled off. It does not appear that having FADEC on the engines would have prevented the accident.

Again, just my interpretation. Feel free to tap off of this or correct me if I'm wrong.
 

CF34-3B1

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FrontierFan said:
Thanks Guys,


Not to bring up old topics, but..

I am trying to determine if the Pinnicle Flt 3701' engines were equiped with a FADEC and if they were not, than could the compressor stall prevention provided by FADEC have helped in preventing the accident.

Any of your thoughts would be helpful.

Thanks

F9Fan


The accident aircraft was a -200

They don't have FADEC
 

FrontierFan

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Thanks for all the help guys.

Any other thoughts are welcom.

F9Fan
 

FreedomAList

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Regional4life said:
I'll be the first to admit that I am not a CRJ driver, so please, anyone feel free to correct me.

What happened with the CRJ engines in the accident, (granted still not completely determined), appears to be a core lock.

"CORE LOCK" is the very, very thin straw that ALPA lawyers are grasping at to divert attention from the pilots (who hosed themselves, truely(!) sorry to say). I AM a CRJ driver, and the MINIMUM airspeed for a windmilling start is 300kts (and more like 335). . . and they NEVER got above 248 kts (if I'm reading the NTSB hearing transcripts right). 0% N2 fan rotation . . . and they dumped fuel on it and tried to light it! Then did it AGAIN! Can you say MELTDOWN? Pilot error followed by pilot panic and more pilot error.

Bombardier tests EVERY INDIVIDUAL CRJ coming off the line for core lock through flight tests - - and in the RARE cases they encounter it, they have break-in procedures to ensure it doesn't re-occur. Three days of NTSB hearings, and it's darned obvious this was 2 chuckleheads doing everything wrong, over and over and over.

Course you don't see that on the ALPA website. Oh no, it's NEVER the pilot's fault, ESPECIALLY WHEN ITS THE PILOTS FAULT. It's "core lock" . . . a sexy sounding, highly unlikely (but admittedly possible) phenomenon that diverts attention from what really needs to be addressed . . . pilot professionalism.


But I'm no engineer :) We'll see what the NTSB rules soon enough. Definitely no FADEC on the CRJ 200. FADEC is the greatest thing since sliced bread, IMHO.
 
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DoinTime

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FreedomAList said:
"CORE LOCK" is the very, very thin straw that ALPA lawyers are grasping at to divert attention from the pilots (who hosed themselves, truely(!) sorry to say). I AM a CRJ driver, and the MINIMUM airspeed for a windmilling start is 300kts (and more like 335). . . and they NEVER got above 248 kts (if I'm reading the NTSB hearing transcripts right). 0% N2 fan rotation . . . and they dumped fuel on it and tried to light it! Then did it AGAIN! Can you say MELTDOWN? Pilot error followed by pilot panic and more pilot error.

Bombardier tests EVERY INDIVIDUAL CRJ coming off the line for core lock through flight tests - - and in the RARE cases they encounter it, they have break-in procedures to ensure it doesn't re-occur. Three days of NTSB hearings, and it's darned obvious this was 2 chuckleheads doing everything wrong, over and over and over.

Course you don't see that on the ALPA website. Oh no, it's NEVER the pilot's fault, ESPECIALLY WHEN ITS THE PILOTS FAULT. It's "core lock" . . . a sexy sounding, highly unlikely (but admittedly possible) phenomenon that diverts attention from what really needs to be addressed . . . pilot professionalism.


But I'm no engineer :) We'll see what the NTSB rules soon enough. Definitely no FADEC on the CRJ 200. FADEC is the greatest thing since sliced bread, IMHO.


You obviously practice very selective reading of the NTSB transcripts. Whats it like to be so ignorant?
 

Regional4life

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FreedomAList said:
"CORE LOCK" is the very, very thin straw that ALPA lawyers are grasping at to divert attention from the pilots (who hosed themselves, truely(!) sorry to say). I AM a CRJ driver, and the MINIMUM airspeed for a windmilling start is 300kts (and more like 335). . . and they NEVER got above 248 kts (if I'm reading the NTSB hearing transcripts right). 0% N2 fan rotation . . . and they dumped fuel on it and tried to light it! Then did it AGAIN! Can you say MELTDOWN? Pilot error followed by pilot panic and more pilot error.

Bombardier tests EVERY INDIVIDUAL CRJ coming off the line for core lock through flight tests - - and in the RARE cases they encounter it, they have break-in procedures to ensure it doesn't re-occur. Three days of NTSB hearings, and it's darned obvious this was 2 chuckleheads doing everything wrong, over and over and over.

Course you don't see that on the ALPA website. Oh no, it's NEVER the pilot's fault, ESPECIALLY WHEN ITS THE PILOTS FAULT. It's "core lock" . . . a sexy sounding, highly unlikely (but admittedly possible) phenomenon that diverts attention from what really needs to be addressed . . . pilot professionalism.


But I'm no engineer :) We'll see what the NTSB rules soon enough. Definitely no FADEC on the CRJ 200. FADEC is the greatest thing since sliced bread, IMHO.

I never said it wasn't the crews fault. I never said there wasn't a lack of professionalism. I was however trying to answer his question and still respect the crew. And. . .no, it's not ALPA lawyers "grasping" at core lock. Keep researching my friend. Even though they test every engine, they (the manufacturer) still can't say it will never happen with engines they put out on line. Anyone remember the DC10 that could never have a triple hydraulic failure? Granted, bad correlation, but don't pin the core lock on the crew.

Not to mention being a seasoned CRJ driver that you are, how many core locks have you trained? Prior to this, would you have recognized or even known what a core lock was? Would you have known the proper procedures in dealing with a core lock? And yes, I know what the speeds are to restart. . .If you also read the manufacturer's description during engine testing and researching core locks, the engine's N2 can still spin up to approximately 190 knots. Yes, they got down to around 170 (all numbers approximate), but as you said, they did get close to 250 knots. N2 should have been spinning at least some. They overtemped one of the engines fairly severely without letting it cool down, causing the core lock.

Unfortunately, ultimately it was pilot error. I don't think anyone doubts that and I feel sorry for the families of the crew and pinnancle airlines. However, there are also some mechanical issues arising out of this as well.
 

millhouse21

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FrontierFan said:
4) Are there any main differences between CF-34 models for all the different aircraft they power (A-10, CRJ-100, 700, ERJ-170 etc. ) besides size and thrust output

Don't forget about the Hoover (S-3B) TF-34 engines. No FADEC on those, BTW.
 

AutoBus

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FreedomAList said:
"CORE LOCK" is the very, very thin straw that ALPA lawyers are grasping at to divert attention from the pilots (who hosed themselves, truely(!) sorry to say).

maybe but "core lock" is possible, even the Beech 1900D had (maybe still does) a core lock problem in cold temps.
 

Well-hung Start

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Caw Loch

I'm not a GE Engineer, but I did stay at a Fleabag Inn last night on my layover......I have a few good points here, so lissen up!......

Core lock is a possibility even WITHOUT overtemping the engines: For each new CRJ aircraft in pre-delivery tests, Bombardier INTENTIONALLY shuts down an engine during high-power operation at altitude. They consider this a high-temperature shutdown, and the intent of this is to INDUCE core-lock in susceptible engines.

The ones that do "lock" (evidenced by inability to generate ANY N2 speed during a CORRECT windmill procedure at >300 KIAS) are then put through a high-tech "grind-in" procedure: starting the engine with the APU to over-torque the bound-up core bearings and wear down the grooves responsible for this lock-up.

A few points from this:

1) There is no guaranty that, even if done properly, a windmill start will succeed. And if done improperly (eg: IAS 248 instead of 335), fuggedaboudit!

2) A sudden stoppage of the engine by fuel shutoff at high altitude is Bombardier's recipe to induce "core-lock."

-------BUT-------

----->A gradual stoppage at high altitude, like happened in the Pinnacle disaster, whilst still pouring fuel into an overtemp engine, is Pinnacle's recipe for "core-melt"

3) Not even Bombardier test-pilots would allow the plane to stall at 158 KIAS at 41,000 without taking extraordinary measures to protect themselves and the airframe from likely damage.
 
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