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Pinnacle Airlines aircraft incident

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Pinnacle Airlines aircraft incident

Old 23rd Jun 2005, 22:55
  #161 (permalink)  
 
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been there done that

The crew here are obviously responsible for the outcome of this unhappy incident, so an element of blame can be fairly laid at their decision to climb to FL410, but their company should have been aware that it was a bit risky. If they were not aware, then they should have been made aware by Bombardier.

I worked for a regional carrier equipped with the CRJ200 and the CRJ700 and the most disappointing aspect of the 200 was that we were promised an aircraft capable of FL410, carrying 50 pax and of flying at M.85!!

It soon became apparent that although it was capable of all three performance targets, it could only do them individually! ie. a full pax load meant FL330 was the max attainable and also left you at max landing weight with only Company minimum fuel at destination.

Since all our pilots were already B737 or BAC1-11 type rated, we mainly just fell over laughing or got annoyed with the Bombardier Company trainers who really rated the CRJ and tried to get us to push the envelope.

In fact, pushing the envelope one day, in order to climb above FL390 to avoid CB activity, and checking with the ICAS2000 FMCthat we could make the altitude!, I got the CONT IGNITION caption and a bit of airframe buffet which led to a curt exchange with Reims ATC which gave me a lower FL after threatening them with a MAYDAY.

What worried me was even after initiating a descent and applying MCT, the bloody aircraft would not accelerate and remained at about M0.686 for nearly 300' until we stabilised level at FL370.

What had caght me out was that the SAT at the commencement of our climb was ISA -2 but by the time we had reached FL390 the SAT had increased to ISA +10 just as you'd expect passing an active weather front, and subsequent review of the performance chart revealed we had climbed about 300' above the CRJ200's service ceiling at our given weight!!

Well didn't I feel stupid.

But not as stupid as my management, who despite reading my ASR and giving me a tea and biscuits, felt that it was a one off.

Could I also add that the QRH for double engine failure does not help the crew make the transition from the windmill relight to the APU assisted relight and it was very common to see crews trying to achieve the rquired N2 during relight below FL130 without realising that they needed to push the start button first!

Although, as 411A points out quite correctly, a lack of experience is an important factor, a lack of training is the major causal criteria and if the Bombardier pilots who trained me are anything to go by, then a lack of experience in their department may also be to blame since they themselves had a mainly ex turboprop (C130 and Beech King Air) or had at best flown heavy jets in the RHS.

So having had the stick shake at FL390 on the CRJ and been ignored when I mentioned it what do you bloody well expect!
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Old 24th Jun 2005, 15:04
  #162 (permalink)  
 
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Ooh! Points scored!

Nailed by another lurking vigilante!

Actually, I get to do sim training every six months, just like a real jet pilot. And I try to fly whatever I am handed to the same standards. When I want to have 'fun' with machinery then I use a motorcycle and not a passenger aircraft. Doh!

My point is that the autopilot (in the 328, at least) seems to be loaded with some fairly simple machine logic. Every so often, usually when one is preoccupied with some other task, it decides to use a 30° intercept despite being switched from 'HDG' to 'NAV' mode when just 3° or so off-track. That sort of thing. Usually it gives a nice, smooth capture, which is cool. Then, once in a while it reverts to 'student pilot' mode and takes a big cut, banking first one way and then the other as it attempts to get right on top of the FMS track. God only knows why!

When you get a wobbly localiser signal (not that uncommon in Africa) of course it chases every deviation, where a human would immediately know what the problem is and hold a steady heading while the needle makes like a windscreen wiper.

I don't know about the rest of you but I was certainly told by those held to be more knowledgable to hold the autopilot in fairly high regard, as if it had some higher abilities stuffed inside its dusty interior. Here I am flying with the best equipment ('airline quality' even) I have ever had the privilege to enjoy, and I find it sometimes doing stuff, when left to its own devices, that is distinctly sub-par. Kindly do not extrapolate from that, that I usually follow the 'set and forget' philosophy.

It is arguably a good idea to know what that device will do on its own, without your micro-management of it. You may not always have the time to watch it that closely, such as when dealing with an in-flight problem. So, sometimes when it doesn't matter much, I just turn it loose on its own. Too, 50% of the time there is someone else doing the flying, when I am usually just doing the comms, reading the checklist and watching what transpires.
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Old 25th Jun 2005, 19:46
  #163 (permalink)  
 
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Hello Mr. hec7or:

I just read your post with great interest – particularly the title of your post and your last sentence. I can’t imagine the frustration you must be feeling right now. Had someone listened to your account, the circumstances leading up to the Pinnacle accident would have been – should have been – avoided. I hope that you’ll take a copy of the Pinnacle accident report and send it to the folks who (from your description) very politely told you to go pound sand – and ask them if they remember your conversation! This business is much too much dependent on accurate and timely information to be able to dismiss such harrowing accounts with polite “chit chat.”

I’m not rated on the CRJ200, but I’m told that the bleed air configuration is pretty complicated and if it is not set up right, restarting an engine would be next to impossible. Another situation that has gone unnoticed for much too long. It’s practical knowledge – borne of experience – such as these accounts that could make the difference between a boring, uneventful repositioning flight, and not coming home to your wife and kids!

I hope that everyone reading this information on this thread takes a moment to evaluate what is heard and recounted, and for the sake of untold numbers of wives and kids, passes it along to their colleagues and anyone / everyone else who will listen! If we can't depend on such information being disseminated through proper channels -- then it must be disseminated through alternate means!

_________
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Old 26th Jun 2005, 14:07
  #164 (permalink)  
 
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Flying at the thin end of the envelope has hidden risks that the certification process does not allow for.

For instance, when I first flew the SJU-GTK-MIA route I was mystified that several times the autothrottle seemed to be having a problem with speed stability. It would sometimes spend several minutes at the high or low end of the normal range just to stay close to target speed.
What I finally deduced was that when the upper winds were strong and out of the West, often there were standing waves way downwind of Hispaniola, and I had been surfing up and down those waves, which were almost parallel to the route.
Now think of an aircraft at max alt, with very little thrust margin left, and throw that type of effect in, and you may have a problem.
At times those standing waves seemed to have the equivalent performance effect of 200/300' per min, but that was subjective judgement.
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Old 26th Jun 2005, 23:15
  #165 (permalink)  
 
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A series of unfortunate events.

There are very few excuses for the crew who flew this particular CRJ on this particular day to this particular altitude and who were unable to relight AT LEAST ONE of the two engines. They should have been able to do that despite switching seats.

According to the Climb capability chart, at 37,800 lbs in ISA conditions they were able FL410. End of story. Anything off ISA and they were out of luck.
Had they flown the aircraft in accordance with the AFM and company SOPs, we wouldn't be discussing this.
Unfortunately, it wasn't ISA at altitude. It was warmer and at that weight the max altitude was lower than 41. Had they checked.

Blame Bombardier? Not their fault.
Blame Bombardier Tech Pubs? The relight procedure is crystal clear in the AOM and QRH. Works well, lasts a long time.
Blame Bombardier Airworthiness/Engineering? Bleed configuration (while awkward) is a no brainer.
Blame Bombardier's Training Center? They didn't train either of these two pilots, FWIW, they didn't train most of the Pinnacle crews.
Blame GE? Both engines were operating fine until someone took the aircraft outside it's performance envelope.
Blame Pinnacle? SOPs are SOPs. Doesn't sound like these two respected, let alone operated, the aircraft in accordance with SOPs. Had they followed SOPs and flown their Company Despatch FPLN to Minney would certainly have ensured there would have been no opportunity to discuss their flight on a public forum.
Blame the FAA GADO/FSDO? Why not? I'm in. Feds get no respect anyway.
Blame Flight Safety Memphis? We'll see.
Blame whomever YOU like! If that's what this is all about?

At the end of the day it doesn't sound like either of these two did much to question the climb performance nor the effort it took to get to 41, as the indications would have certainly been there, nor did they even seem to consider the cost of operating off optimum like that. Judging by the result of that decision I'd say that is a moot point.

I've read enough. I've listened to enough. I've drawn my own conclusions.

The ever increasing rush to fill flight decks with minimal/questionable experience levels is only going to see an ever increasing number of these "unfortunate events" as a gaping hole in flight training widens and deepens.

These two individuals, while they may not have known or realized it at the time, role modelled an excellent script for a movie sequel, called DUMB AND DUMBER II.

The one wish I do have out of all this is a genuine wish they'd both survived so they could be despatched to the safety lecture circuit to explain what the HECK they were thinking and what they'd learned!!!


On a more somber note, my heart felt condolences to their survivors.
May God keep and rest their souls.
and...
There, but for the grace of God, go I.

Last edited by Willie Everlearn; 26th Jun 2005 at 23:31.
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Old 27th Jun 2005, 13:09
  #166 (permalink)  
 
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Well Willie, this better not be about blame except for the unimaginative, this discussion ought to be about what it takes to fix it the easiest.
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Old 27th Jun 2005, 17:51
  #167 (permalink)  
 
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lomapaseo

How right you are.
I had said "Blame whomever YOU like! If that's what this is all about?" This isn't exclusively about blame but blame will definitely be apportioned.


I can only imagine how many pilots out there are pulling these kinds of stunts off on a regular basis out of ignorance. Not just on the CRJ either.
Scary, isn't it?

There are definitely systemic problems in this disaster. Chiefly, training. What these individuals lacked will surface. I have no doubt.

As a TRI on the CRJ I am appauled by the number of students showing up for training who are so lacking in 'jet aerodynamics' knowledge (to name just one area) it's unbelievable. These people think all they have to do is listen and learn.

How do they deal with the things they don't know? Do they not want to use their own initiative to seek out what it is about the things they don't know? Ask questions? Read? Share their experiences?

Perhaps. Perhaps not.
It's easier to BLAME someone else for these shortcomings and deficiencies.
Not that it should be news either.

You can bet the NTSB will have a lot to say about regional airline and training center cirriculum when this investigation is over. We might even see a change in those FAA written exams if all goes according to Hoyle.
Maybe it's time to do some actual learning instead of memorizing answers from some huge database.
The knowledge otherwise gained might come in handy on a dark and dreary night.

Maybe that's a good thing.
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Old 28th Jun 2005, 00:23
  #168 (permalink)  
 
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Willie

I agree

Now what's it going to take to drive this discussion and the near miss at Boston in the direction of working a fix with the avialble resources and infra structure. We sure as hell can't afford the time it takes to change plane manufacturers,governments and national flags to solve aviation disasters.
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Old 28th Jun 2005, 07:57
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Mr. Air rabbit,

After reviewing the documents most pertinent to this occurance, perhaps you will be willing to share your reaction to the facts as they are presently available for everyone to see.

http://www.ntsb.gov/Events/2005/Pinn...ts/default.htm

The NTSB will release it's opinion of these facts in due course. Barring any radical revisions to the current state of the facts, most of the story is clear enough to draw a few conclusions. The only unresolved questions relate to the events following the stall. Namely, to find the precise reason why an airstart was not successful on at least one of the engines. The right engine overtemped so severely (FDR data) that it may indeed have been locked up due to thermal damage and incapable of running. I did not find any indication that the examination of either engine has been completed. Is core-lock phenominon (sudden cooling causing a loss of operating clearances) a factor which explains why the left engine was not restarted? This is being investigated. Or did the extreme stress and time pressure of this situation lead to a crew failure to properly configure the bleed system to attempt a start on the left engine? It would be handy information to have in case this scenario (dual engine failure) ever occurs again, perhaps as the result of encountering CAT, wake or aggressive maneuvering to avoid collision. The parties to the investigation must be very interested in this question. I know that I am.

If commenting on the implications made by the currently available facts offends, that is a shame. As for the effect that "seeing pilots villified" may have on up-and-coming pilots, sometimes the facts are unpleasant but that is not a good reason to attempt to censor it by using indirect references to chide others. Please be forthright and speak clearly to make your point, whatever it might be. There are several valuable lessons to be learned here. The real utility of sites like this one is that it provides an open forum for reasoned discussion and exchange of ideas. Or to let off steam! While I agree that rampant and uninformed speculation is certainly not appropriate, discussing the implications raised by the published facts certainly is. So is commenting on the poor taste exhibited by Pinnacle management when they denied any responsibility for the crash by putting ALL of the blame on the crew and none on themselves in public statements. Perfectly understandable from a business standpoint, but still not very laudable, to say the least.

Best regards,

Westhawk
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Old 1st Jul 2005, 08:38
  #170 (permalink)  
 
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Pinnacle

I wonder if by 'firewalling' the thrust levers they severely damaged the engines. I understand it is not (Pinnacle) company policy to 'firewall' but in my experience with pilots from US carriers this is commonly taught. I recall one incident when an aircraft stalled in holding at 20,000 feet. By firewalling they ruined a few of the engines. If there is a possiblity of ground contact - sure. It is all about risk/reward. But at high altitude......
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Old 1st Jul 2005, 12:26
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Firewalling throttles (oops, thrust levers...) should not cause short-term damage to modern engines - the acceleration fuel schedule is computed irrespective of throttle position in all fuel controls that I've worked on for the last (expletive deleted) years.

Granted, this technique may not be the best for long-term performance preservation (fuel burn, turbine temp. margin), so the accountants may not like it - so if that's an accountant sitting next to you -
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Old 1st Jul 2005, 13:56
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Unhappy

Barit1 - I can absolutely assure you that on the MD-82/83 series of 'modern' airliners if you slam the throttles you probably will do some blade distortion or overtemp. That's because the pathetic JT8D-217/219's have ancient hydro-mechanical fuel control mated to their 'modern' engines, with no limiters. MD ran out of development money to truly modernise their creation back in '81, leaving just a souped-up DC-9.

But, agreed, on the RJ with FADEC, probably not.
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Old 1st Jul 2005, 15:16
  #173 (permalink)  
 
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CRJ200s do NOT have FADECS. The engines are hydromechanically controlled and it is very possible to cause engine damage if you simply push the throttles as far forward as they will go. The maximum thrust rating for a given condition is set by moving the throttles to achieve a specific N1 value, which usually does not correspond to maximum throttle travel. At any point beyond that, you're exceeding the cleared engine operating envelope, and introducing a risk of engine damage of various degrees.
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Old 1st Jul 2005, 19:56
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I can absolutely assure you that on the MD-82/83 series of 'modern' airliners if you slam the throttles you probably will do some blade distortion or overtemp. That's because the pathetic JT8D-217/219's have ancient hydro-mechanical fuel control mated to their 'modern' engines, with no limiters. MD ran out of development money to truly modernise their creation back in '81, leaving just a souped-up DC-9.

But, agreed, on the RJ with FADEC, probably not.
the last I knew was that the MD-82/83 was certified to an "R" or reserve thrust rating which automatically kicked the thrust up to an overboost when it sensed a drop in EPR on the other engine.

By certify it means that no damage will occur to the engine.

To my knowledge most hydro-mechanical controls do have limiters such as RPM, pressure and in some rare cases temperature to restrict the engine from blowing itself up..

It is indeed hard to imagine how you can command over-meter fuel to an engine that hasn't even started yet.

Of course you can still burn out the turbine with min fuel flow simply by starving the burner of pressurized air.
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Old 1st Jul 2005, 21:45
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It is also possible that with climb thrust set, that stall induced turbulent airflow at the engine inlet(s) could cause a rapid rise in ITT exceeding the maximum limit. I am not familiar enough with the CF-34 engine control system to know whether it has a temperature limiting device capable of limiting a rapid ITT rise. I recall that it does have some kind of limited electronic engine control unit that takes effect at higher N1 speeds. Perhaps someone with the technical manuals could comment.

I have noted during my simulator training on two bizjet types that both of the major training providers teach the "firewall the levers" method for stall recovery and go-around/missed approach maneuvers. Unlike the real airplanes in the fleet, the sim will not overtemp/overspeed. In aircraft equipped with DEECs or FADECs, this will not harm the engines because the modern digital engine control will simply set max thrust very precisely while observing limits. However, on the aircraft I currently fly, this is a really bad idea. Very large exceedences are possible if you apply "radar power"! The older analog EECs do not anticipate limits. They do not act to limit ITT or RPM until after limits have been exceeded. During a rapid change of engine speed, the limits can easily be grossly exceeded just like they can on the purely hydro-mechanically controlled engines. I have mentioned this to the instructors and managers at the TCs. I was informed that this is the method they are required to teach. I don't know why. So I go with the flow at training and operate the real engines with greater care than they advocate. I guess it is another case of what looks good on paper versus the real world!

Best,

Westhawk
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Old 2nd Jul 2005, 07:02
  #176 (permalink)  
 
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Mr. Westhawk (et al):

Methinks ye may have read too much into my earlier post. I was not, in any way, chiding you – quite the contrary – my sincere compliment was directed toward all who seemed to have a more professional approach to the circumstances and media “buzz” surrounding a post-accident inquiry such as this – and particularly to yourself! If you misunderstood my attempt to compliment you, I apologize.

I completely agree with you about the utility of forums such as these! It is my opinion that you and I do not disagree on the value of post-accident discussions -- and any disagreement that may exist (or come to light) is very likely to be almost exclusively due to my past experiences – which, as I’ve indicated, have not always been what professionals would desire. As a result, I am, and I’ll probably continue to be, very cautious when leaping into discussions about post-accident information that “leaks” out or is published as preliminary findings. Please understand, when the facts are that a pilot has screwed up, you’ll not find me trying to white wash the concept. But I do hope that in my comments about such a pilot one would not find my focus on the fact that he screwed up, but rather would find my focus on what can be learned so that other pilots will be less likely to find themselves in similar circumstances and prone to make the same mistakes.

Please understand, I am not offended, at all, by examining the evidence and following it wherever it leads. What I was cautioning against, and what I will continue to caution against, is that we don’t jump to conclusions or attempt to find justification for preconceived opinions. My overall impression is that this occurrence developed because two pilots decided, for whatever reason, to abandon their normal operating procedures – and one could certainly surmise that this was done because, in their eyes, “the rules are relaxed when we don’t have passengers aboard.” They apparently elected to use the autopilot climb rate rather than speed (airspeed or mach – I don’t know the autopilot setup in the CRJ). Both crewmembers seemed to recognize that this was a “non-routine” event, decided upon to “have some fun.” Had they elected to use the speed mode, there is a chance that they would have realized that FL410 was beyond the airplane’s capability that night. And, after reaching FL410, the Captain left the cockpit and the F/O apparently didn’t believe it necessary to don his O2 mask. Was this a symptom of the “relaxed rules” thinking? Both pilots apparently recognized what was an “unusually high pitch attitude.” They both apparently realized that their airspeed was slow and getting slower. They both apparently recognized that they were not going to be able to sustain that altitude. I’m not at all sure what other clues may have been necessary to suggest to them that they were where they shouldn’t be and that they should do something about it – right now.

However, whatever clues may have been available were not used and the problems began. What about them? At first look, it would seem that a lot, quite a lot perhaps, and some would say virtually all, of the information necessary has been obtained and all that is left is the sifting of that information and reaching a conclusion. My experience has shown that very often it seems that some of the most pertinent questions go unasked – and therefore unanswered. It is also my opinion that in at least some circumstances an observer’s opinion of the situation may well color the observation being made. For example: looking at the FDR traces and reading the narrative that accompanies those traces – it would appear that the investigator has concluded that after the stick shaker activated, followed by the stick pusher firing, one of the pilots pulled the control column with a force calculated to be 25 pounds and then released the control pressure.

The questions that I would have thought should have been raised during the discussion that led up to this statement would have been the following:
1) Other than pilot action, what could cause the autopilot to disconnect?
2) If there were no pilot intervention, would the stick shaker activation electrically disconnect the autopilot?
3) If not, would the stick pusher activation electrically disconnect the autopilot?
4) If not, would the stick pusher cause physical pressure on the control column that would override the autopilot and result in a “brute-force” disconnect of the autopilot?
5) Does the stick pusher provide a forward control column movement to a specific attitude, to an angle of attack, or to some other parameter?
6) At what point does the stick pusher disconnect?
7) If there were no pilot intervention, given that the autopilot may have been disconnected because of an overpowering of the pitch attitude to which the autopilot had trimmed the airplane, what would be the expected reaction of the airplane upon stick pusher release?
8) If, upon stick pusher release, would it be expected that the airplane would attempt to return to the previously trimmed condition?
9) If so, would this physically move the control column?
10) If the control column would be expected to move, what would be the recorded movement and could that be interpreted to be a 25-pound pull on the control column?
11) What would be the effect of decaying airspeed on any tendency to return to a previously trimmed flight condition?
12) If there were no pilot intervention, what would be the expected short term response of the airplane?

A second series of questions that might have been asked might have included the following:
1) During training for recoveries from approaches to stall, in those circumstances where the pilot allowed the stick pusher to fire, what were the tendencies of that pilot during and immediately after the stick pusher activation? In other words, was the pilot attempting to dampen the stick pusher input during its input? And if so, what did the pilot do with the controls when the stick pusher deactivated?
2) If the pilot was actively pulling on the controls during stick pusher activation, did the pilot tend to over-control the pitch when the stick pusher deactivated?
3) If so, did the pilot tend to enter a secondary stall / stick pusher event?
4) If so, did the pilot attempt to dampen the second stick pusher input – as he did initially?
5) If so, what were any continuing actions between the pilot, the stick pusher, and the pitch attitude?

I see no evidence that these, or similar questions, were asked/answered nor do I see any information provided to understand that this information was made available. Prudence, I would have thought, would have required these answers or, at least, a discussion of this information would have been necessary to enlighten the on-going investigation. I say this because it would appear, from investigator statements, that a phugoid-type of oscillation occurred.

This airplane has a particularly disagreeable tendency to “dutch-roll” (rather significantly I might add) when the yaw damper is disengaged – and this is particularly true at higher altitudes.
With the loss of electrical power (when the engines failed) did the yaw damper control disengage? If so, was it ever re-engaged? If not, did a “dutch-roll” develop?

In talking with several persons close to the investigation, I understand that a careful analysis was made of the number of times a bleed-air re-configuration was made during the futile attempts to start one or both of the engines. I understand this configuration was changed some 16 times by one or both of the crew. I also understand from persons knowledgeable about the CRJ200, that while not an overly complex panel, if just a single error was made in that configuration, it would be unlikely that someone would have been able to retrace the selections made to negate the initial error.

In my very brief review of the “core lock” phenomena, I wasn’t able to fully digest the causes and/or if there were any in-flight resolutions to that particular problem. I believe that it is, at least, noteworthy, and perhaps worthy of more scrutiny, to recognize that it was apparently a routine practice that engines undergo “core lock” testing before being shipped. I would think that someone would want to ensure that a correction to eliminate that potential would be appropriate prior to releasing such an engine for revenue service.

In reviewing the transcript of the CVR, it seems to me that the Captain was content to let the F/O continue to fly for quite a while. Later, when he decided to take control, it appears that he was about to deal with an emotional situation that was likely to result in losing his F/O from conscious participation; and I believe the Captain did quite a nice job of returning that F/O to the job at hand without spending unnecessarily long in the process.

It sounded to me like the primary concern of the Captain was getting the engine to start – and because of that focus, the focus of the F/O was directed largely to that end as well. He seemed to be riveted on that problem – almost to the exclusion of the flight status of the airplane (where they were headed, the rate of descent, etc.). In fact, it seems to me that he was so intent on getting the engine started that he was willing, saying so on a couple of occasions, to trade altitude for airspeed to wind mill the engine to facilitate a start.

So, is it training? Should the airline have provided high altitude simulator training? Should all airlines do this? I am under the impression that the FAA Flight Standardization Board Report on the CRJ200 did discuss recommended training or familiarity (I haven’t read the report) with high altitude operations, specifically regarding the tendencies for dutch-roll, and I believe it referenced the complexity of the bleed air control panel for engine starting. Perhaps it is past time that the FAA make that report a regulatory requirement instead of a set of recommendations that may or may not be heeded by the industry. Should simulators be qualified only after demonstrating that they do, in fact, perform and handle at high altitudes, just like they do at intermediate and lower altitudes? Should we begin training crewmembers on recovery from stalls rather than training on recovery from approaches to stall? Should we require each crewmember to understand the power-off glide ratio of his/her airplane and practice dead-stick approaches from above FL400 in the simulator? Do we require direct reading AOA indicators in commercial airliners? Do we go back and review each ground training program for its inclusion of high altitude operations and the effects of temperature inversions, lapse rates, density altitude, service ceilings, etc.?

It is almost easy to answer in the affirmative to most if not all of the questions here. But I recognize that training is an expensive effort, particularly today. Airlines are not rolling in money – they must spend it wisely. Training is always “on the bubble;” and it is primarily because of the costs involved in training. Should the regulator step in and mandate these things – regardless of the cost? The arguments on both sides are substantial – and what usually results is an attempt to find a happy medium between the two opposing points. However, it is my experience that in doing so, there is rarely any “happy” and almost never a “medium.”

I recognize that I have only raised a lot of questions and haven’t really taken on the answers to many of them. Its not that I can’t or won’t. It’s just that this post is already much too long. I don’t have any problem with providing anyone here with my opinion of what the answers to some of those questions should be – but I’ll wait to see if anyone is really interested in hearing any more of what I may have to say. Until then, I’ve probably said enough – at least for now.

________
AirRabbit
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Old 2nd Jul 2005, 09:38
  #177 (permalink)  
 
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AirRabbit,

Thank you for your well considered reply. I can see by the questions you still have that you have given this matter quite a bit of study and thought. My apologies for misunderstanding your intended meaning in your earlier comments.

Those FDR traces would sure be easier to interpret if I could line them all up in parallel on a very large screen! At least one important step remaining to be completed is the analysis section of the final report. But alas, we will probably have to wait another year for the final report. Based upon my reading of past major investigation reports, I think that is the most likely place to see your questions addressed if indeed they ever are. I feel fairly confident that the events leading to the stall are pretty clearly described by the FDR and CVR data, making it possible to reach a few conclusions and find some lessons learned in the flight up to this point. These lessons related to general airmanship and aeronautical knowledge have been discussed in several posts. No need to repeat them.

As an aside, I would like to share my personal observations on the performance of the autopilot when coupled to the F/D while it is selected to IAS or mach hold. (to include FLC in Honeywell integrated EFIS systems.) In the Collins and Honeywell equipped aircraft I have flown, when these speed hold modes are used, there is a distinct tendancy for the aircraft to "pitch hunt". To avoid having to tolerate this condition of constant pitch changes, I and most pilots I have flown with prefer to climb these aircraft in VS mode since it results in a more consistent pitch attitude. It is a little bit more work to closely monitor the speed and occasionally adjust the desired vertical rate to stay on speed schedule, but it's worth it. Once you are in the habit, it works very smoothly. I do not know if this tendancy is common in the CRJ as I have not flown one. Maybe a CRJ pilot could comment.

It is the events following the first indication of aerodynamic stall that I find require further analysis for me to understand what took place from this point on and how this knowledge might be applied to benefit other pilots facing similar circumstances. It is clear that once the descent began, they were under a lot of pressure to find their "A" game and right soon! From this point in the sequence, the events should be analyzed without regard to how they got into this mess, since the next crew to face this situation could find themselves there as the result of a completely different cause like turbulence, etc.... GE data provided to the board indicate that in all documented tests, "core-lock" was overcome by torque from the starter when used. I hope this is proved to be the case.

Time to hang it up for now. Gotta fly in the morning.

Best regards,

Westhawk
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Old 3rd Jul 2005, 19:59
  #178 (permalink)  
 
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Howdy Westhawk –

I read your comments on the function of the autopilot’s tendency to “pitch hunt;” and I certainly agree that this is a most disconcerting and uncomfortable action that most pilots, including me, would want to avoid. That may well be the reason these guys chose the mode of operation they chose – but, as you pointed out, it’s “more work to closely monitor the speed.” The part that I think these guys missed is the “…occasionally adjust the desired vertical rate to stay on speed schedule” and, I believe that is because of the attitude they adopted that “the rules are relaxed when we don’t have passengers aboard.”

However, having said all that – I completely agree with you that it is important to know what happened after the aircraft was allowed to get into the sick shaker / stick pusher realm of operation. The material that is available on the FDR, as informative as it is, could be a lot more informative if the questions I’ve suggested were asked and answered. I fear that the reason these or similar questions were not asked and answered, is that someone (perhaps several someones) with some degree of authority (and in my book, that is what is important), concluded that the FDR and CVR data was singularly sufficient to reach the necessary conclusion(s).

I reiterate, without the additional information that could have been supplied by answering those questions (or similar ones), the conclusions reached, at the very least, have an opportunity to be less than fully developed. IF that is an accurate position (and obviously I believe it is) then the conclusions reached – any and all conclusion regarding this portion of the accident profile – is going to be, at best, incomplete – and, I believe, very likely to be misleading to a very deserving and perhaps due to this, still vulnerable, aviation industry. I don’t understand an attitude that would allow this to occur. And this potential is the basis that formed my earlier admonitions to be sure that ALL of the facts were considered before reaching conclusions.

The point is that the crew may very well have done exactly what the synopsis of the investigators indicates; and there may be no additional areas of “fault” that came into play. However, unless some additional information is gathered and considered as to whether or not the airplane itself played a more substantial role in this tragedy, we may be wrongly blaming only the crew (certainly their family, friends, and co-workers have enough to occupy their minds without having to endure additional accusations, particularly if incorrect) and ignorantly allowing a potential problem with a machine continue to lurk in the darkness of that ignorance, awaiting an opportunity to spring to light, this time with a full load of passengers!

I guess we’ll all have to wait, see, and pray.
_______
AirRabbit

Last edited by AirRabbit; 3rd Jul 2005 at 22:13.
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Old 4th Jul 2005, 15:49
  #179 (permalink)  
 
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Related somewhat. This is Air Canada Jazz

on Thursday June 9th one of the new model CRJ-705s being flown by Jazz Air between Houston and Calgary had a stick shaker incident near Colorado Springs. The aircraft (C-GJAZ) was at FL410 and was at Mach 0.70 when the flight encountered a downdraft and the stick shaker activated. Maximum thrust was set and a lower altitude was requested. The airplane descended at approximately 1000 fee per minute with a 3 degree nose down attitude. An attempt to recover at flight levbel 4000 was made but the stick shaker activated briefly and the descent was continued. Recovery was made at flight level 380 and the airplane returned to a planned speed of Mach 0.77. There were 62 passengers on board and no injures were reported. The Transportation Safety Board of Canada has secured the flight data recorder and has provided an accreditted representative to the investigation. The NTSB will be conducting the prime investigation since it happened over U.S. airspace.
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Old 4th Jul 2005, 18:05
  #180 (permalink)  
 
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A remarkably similar event occurred the following day: 10 June

(If that link fails, search on the www.ntsb.gov site for document
DCA05WA073 )
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