CRJ Engines

[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.