CRJ Engines

[redflyer65]

Eagle, They did restart the APU and had it avaliable to them below 15k. The engine still wouldn't start. But you are right on the initial relight envelope, they never achieved the airspeed that they should have maintained.

This one part of the accident is where GE will try and hang their hat. They have know other choice. Their defense will be that the pilots never maintained the stated airspeed so how can our engines be defective? It will be sort of a lame arguement, because like others that have stated on here, I would like to know that the engine will spin when I hit the button in a critical situation.

All CRJ operators should have had this information available to them years ago. Not after an accident.

All the test flights have the luxury (obviously for safety) of having the APU running. When the engines did core lock during the test flights, they were restarted each time with APU air, not windmilling. So what's the difference in 3701? I would like to know.

 

[Tarzan]

So what's the difference in 3701? I would like to know.

Maybe the fact that the engines were well above redline on the temps for a period of time. Once you operate outside of parameters, you're a test pilot. Obviously didn't work out for those guys.

 

[Dumb Pilot]

Maybe the fact that the engines were well above redline on the temps for a period of time. Once you operate outside of parameters, you're a test pilot. Obviously didn't work out for those guys.

Again, this information is incorrect. One engine went to 1200+ degrees this is true, but the other engine just quit and the temperature decreased rapidly, That is the issue at hand in terms of what do we know and don't know about the core lock issue. This particular engine should have started and it didn't even with APU bleed supplied to it. The FDR shows that the bleed valves where in the correct position and that the APU was supplying air for a start but still the engine did not spin. I'm not saying that I accept their behavior of course, but there is more to this story and I for one would like to see GE do more realistic test at the actual temperatures that we fly normally and not at 10,000 feet with relatively benign temperatures that not truly represent the temperature shock that these metals get exposed to when you shut them down from 800c and expose them to -40c in a matter of just a few seconds. The testing parameters currently used do not reflect the severity of this temperature shock unless you happen to be flying at 10,000 feet.

 

[redflyer65]

DP is right. I mean think about it. These guys were idiots, let's put that part of it behind us for a second and learn why the other engine didn't start. I would think that any professional CRJ pilot on this board would want to know the same question.

Engine typically don't just shutdown, but as pointed out before there are numerous scenerios where something like this could happen. GE needs to be held accountable to the core lock issue. I don't want to be a glider when they say it was 'supposed' to start, oh well.

 

[pilotdiscretion]

Hey, dumb pilot. You're not so dumb. Were you part of the investigation or did you take the time to read the information in the public docket? I ask because you are the first person on this board to get it right.

 

[PCL_128]

Wow, lots of ignorance on this board, but that's really no surprise.

1. The APU was started and available for engine start. It didn't turn the engine as advertised.

2. Only one engine was cooked, but the investigation revealed that even it should have been able to start and idle, just not spool up to full thrust. The other engine was undamaged and should have operated normally. It did not.

3. Prior to this accident, no operator of the CRJ was aware of the core-lock concern with these engines. GE and Bombardier kept a very tight lid on it.

4. The core-lock tests and grind-in procedures were only done on the engines that were hung on the aircraft when it was delivered. New engines that are sent to WV to be hung on old airplanes are never tested for core-lock and never receive a grind-in procedure. The engine that was undamaged and still didn't start in this accident was installed in WV and never received a core-lock test.

5. The FDR data and recovered switches from the crash site reveal that the APU-assisted engine start procedures were accomplished correctly by the crew. The engines should have started, but did not.

6. You can call these guys idiots all you want (and I'm not necessarily disagreeing), but dual-engine flame-outs and core-lock can result from many circumstances outside of your control. An example would be a Comair CRJ that was struck by lightning over CVG. The lightning strike interupted airflow to the engines just long enough to flame them both out. The crew glided into CVG and landed without further incident, but this is a perfect example of how you can find yourself in a dual-engine flameout situation through no fault of your own. Wouldn't you like to know that your engines will restart?

 

[wmuflyguy]

6. You can call these guys idiots all you want (and I'm not necessarily disagreeing), but dual-engine flame-outs and core-lock can result from many circumstances outside of your control. An example would be a Comair CRJ that was struck by lightning over CVG. The lightning strike interupted airflow to the engines just long enough to flame them both out. The crew glided into CVG and landed without further incident, but this is a perfect example of how you can find yourself in a dual-engine flameout situation through no fault of your own. Wouldn't you like to know that your engines will restart?

This happened when? or are we talking hypothetical?

 

[PCL_128]

This happened when? or are we talking hypothetical?

I don't have the details with me on the date, but it did indeed happen several years ago. I can look for the details and get back with you in a few days if you'd like, but I'm sure your safety committee reps would have the data available also.

 

[328dude]

I don't have the details with me on the date, but it did indeed happen several years ago. I can look for the details and get back with you in a few days if you'd like, but I'm sure your safety committee reps would have the data available also.

So much for going mach 2 with your hair on fire.

 

[wmuflyguy]

I don't have the details with me on the date, but it did indeed happen several years ago. I can look for the details and get back with you in a few days if you'd like, but I'm sure your safety committee reps would have the data available also.

I'm just curious, I went through the NTSB reports for Comair and didn't find anything, they went back to only about 2000 though.

 

[PCL_128]

I'm just curious, I went through the NTSB reports for Comair and didn't find anything, they went back to only about 2000 though.

It might have been before 2000. Can't remember off the top of my head. I remember at the time of our accident two years ago that the Comair event had been a number of years earlier, so it's been a while. It might not show in the NTSB reports since it doesn't technically qualify as an accident. The best source of info would probably be your safety guys or the company training department.

 

[PeanuckleCRJ]

I do remember that the Comair incident is the reason why we have the Cont ignition-on limitation in the vicinity of t-storms now.

Very good points Dumb Pilot and PCL_128.

 

[sinkrate]

All CRJ operators should have had this information available to them years ago. Not after an accident

Every CRJ pilot has had that information since the first AC was placed in service. It is in the QRH in the 'Dual Engine Flameout' checklist. The 'Target Airspeed' that is a memory item is well above the best glide speed given to you later in the procedure. It is also considerably faster than every airspeed in the VMD charts. The 'Target Airspeed' is the minimum speed you need to keep the engine turning. I cannot understand all the discussion about this point. I understood this clearly during my initial training in the AC.

Core lock is nothing new - the CF-34 is a 30 year old engine. It is not unique to the CF-34 either. It is just something else the back pack generation never bothered to learn about.

But all this is irrelavant any way. One of the first things you learn about high altitude stalls is the engine is going to compressor stall - retard the throttles to save it. One of the interesting systems lessons that came out in the hearings was that the stall computer, at altitude, is programmed to push well before aerodynamic stall to prevent compressor stalls. I did not know that. If the engine compressor stalls then flames out, keep enough speed to keep it turning. If the core stops turning you are probably going to have a bad day. It's been that way since the 1950's. I wasn't there then but the guy's that trained me were.

Mountian wave turbulence or CAT can cause a momentary compressor stall, for any jet engine, that rarely results in a flame out. None the less, most manufacturer's have a requirement to turn the ignition on if the engines are not equiped with an auto ignition system.

All this is why I work very hard at avoiding turbulence and staying above VMD at all times.

 

[Papa Woody]

Every CRJ pilot has had that information since the first AC was placed in service. It is in the QRH in the 'Dual Engine Flameout' checklist. The 'Target Airspeed' that is a memory item is well above the best glide speed given to you later in the procedure. It is also considerably faster than every airspeed in the VMD charts. The 'Target Airspeed' is the minimum speed you need to keep the engine turning. I cannot understand all the discussion about this point. I understood this clearly during my initial training in the AC.

Core lock is nothing new - the CF-34 is a 30 year old engine. It is not unique to the CF-34 either. It is just something else the back pack generation never bothered to learn about.

But all this is irrelavant any way. One of the first things you learn about high altitude stalls is the engine is going to compressor stall - retard the throttles to save it. One of the interesting systems lessons that came out in the hearings was that the stall computer, at altitude, is programmed to push well before aerodynamic stall to prevent compressor stalls. I did not know that. If the engine compressor stalls then flames out, keep enough speed to keep it turning. If the core stops turning you are probably going to have a bad day. It's been that way since the 1950's. I wasn't there then but the guy's that trained me were.

Mountian wave turbulence or CAT can cause a momentary compressor stall, for any jet engine, that rarely results in a flame out. None the less, most manufacturer's have a requirement to turn the ignition on if the engines are not equiped with an auto ignition system.

All this is why I work very hard at avoiding turbulence and staying above VMD at all times.

Sorry to quote the whole message, but this is absolutely correct and on-point.

 

[ChickenSled]

PCL_128: Is this what you were talking aout?

http://www.ntsb.gov/ntsb/GenPDF.asp?id=CHI93IA280&rpt=fa

CHI93IA280

On July 24, 1993, at 0840 central daylight time (CDT), a Canadair CL 600-2B19, N915CA, operated by Comair Airlines of Cincinnati, Ohio, as flight number 3707, and piloted by airline transport rated pilots, experienced a right engine failure after being struck by lightning during a climb to its assigned altitude. The 14 CFR Part 135 passenger revenue flight was operating on an IFR flight plan in instrument meteorological conditions. The airplane sustained minor damage. The two pilots, flight attendant, and eighteen passengers reported no injuries. The flight departed from Chicago, Illinois, at 0730 CDT.

The captain's NTSB Form 6120.1/2's written statement reveals the airplane was "... flying through intermittent, moderate precipitation, and moderate turbulence... ." The captain stated, "We just started a deviation to the east, left of course, to avoid a level one cell (thunderstorm)... ." After being struck by lightning several times the pilot declared an emergency at 27,000 feet when the right engine ceased operating. Shortly after descending through 15,000 feet the engine was restarted during a second attempt. The pilot requested, and was granted, a clearance to the flight's original destination.

The company's Chief Inspector of Maintenance stated N915CA had many burn marks on its fuselage, wing, right engine, and elevator. The company's chief pilot stated it was his belief the lightening strike caused an interrupted airflow into the engine resulting in the flameout.

Investigation into the chief pilot's statement revealed a NASA publication entitled: LIGHTNING PROTECTION OF AIRCRAFT, published during October 1977. According to this report, the turbojet engine's flameout is a "...result from disruption of the inlet air by shock wave associated with the lightning arc channel sweeping aft along a fuselage. This channel may indeed pass close in front of an engine intake, and if a restrike occurs, the accompanying shock wave is considered sufficient to disrupt engine operation."

 

[Inconceivable]

This is one of the rare cases where everyone is right:

--the operating crew was "less than vigilant"

--the operator was not aware of the core lock phenomenon--they refused offers of technical assistance from CMR and their pilot group while setting up their training program

--PCL's training program was developed initially by FSI at ERAU by graduate students who had no operational experience and later revised by check airman with relatively brief experience in type--to save the costs of purchasing the Bombardier training package

--the manufacturers addressed core lock (indirectly) through the use of memory items

--the "backpack generation" have never been taught high-speed aerodynamics or core lock. Some WERE taught AMR's now-discredited "Advanced Maneuvering Program" that ripped the tail off an A300 in 11/2001


No surprise, when you pay peanuts, you get monkeys. When you don't train your monkeys, chaos follows. The lack of civilian deaths is why the resulting investigation, fascinating to professional airmen, will change absolutely nothing. In the past two years hiring standards have continued to decline.

Be careful out there.

 

[PCL_128]

ChickenSled, I'm not sure if that's it. I could have sworn that it was a dual-flameout in the incident I was referring to, but I could be wrong. It's been a couple of years now since I looked at this.

 

[Amish RakeFight]

Core-Lock

Here's a Bombardier PowerPoint presentation on Core-Lock.

http://www.ntsb.gov/Events/2005/Pinnacle/exhibits/323843.pdf


Here's another document submitted by GE to the NTSB discussing the Core-Lock issue and how it occurs with the CF34.

http://www.ntsb.gov/events/2005/Pinnacle/exhibits/324090.pdf

 

[DiverDriver]

.......

 

[EagleRJ]

--the "backpack generation" have never been taught high-speed aerodynamics or core lock. Some WERE taught AMR's now-discredited "Advanced Maneuvering Program" that ripped the tail off an A300 in 11/2001

Not to drift the thread, but the "backpack generation" are taught high-speed aerodynamics in class at most airlines. Most regional aircraft (notably the Embraer 145 series) have very forgiving flight characteristics, are are nothing like first-generation jet airliners like the 707, DC-8, or CV-880. Not to say they still can't be abused, but there's a lot more leeway protecting the pilots (who are no more inexperienced than the pilots who were moving up from the DC-6 or Constellation 50 years ago).

And AAMP is still a valued part of pilot training. It's disingenuous in the extreme to blame AA587 on AAMP. Recognizing the limitations of Part 25 is something we're all going to have to do in the wake of 587, but AAMP teaches things that are still of great benefit, and could have saved numerous aircraft (like all those 737s). The primary concern with AA587 is how Airbus could have certified a rudder system that is as unprotected and hypersensitive as the one on the A300.