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CRJ Engine Questions

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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?
 
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.
 
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.
 
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.
 
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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