Pinnacle Accident

[Lear70]

Lear 70,

One of the real tragedies here is that line pilots are not taught how much nose pitch attitude will be required for a relight on your average turbofan-powered jet with all engines flamed out. Core-lock or not, those guys never pushed anywhere enough to get those motors rotating. I don't know what the numbers are for the CRJ, but most twin rear mounted engined jets require in the neighborhood of 25-30 degrees for sufficient airflow.

You're absolutely right about the training, although they've started incorporating it into recurrent PT sims.

In the CRJ it's approximately 12-15 degrees nose-down to get those speeds, this aircraft is pretty slick aerodynamically. You're absolutely right however, they never reached the speed (although they got pretty close during the first part of the descent).

Either way, the last restart they tried to do was at low altitude, and it certainly should have rotated at least SOME... but it didn't. Absolutely flatline zero.

 

[dbert]

(although they got pretty close during the first part of the descent).

Not sure I agree.
http://ntsb.gov/Events/2005/Pinnacle/exhibits/316970.pdf#page=49

Either way, the last restart they tried to do was at low altitude, and it certainly should have rotated at least SOME... but it didn't. Absolutely flatline zero.

This I do agree with. See same FDR data, again page 49 if the link above does not take you to that page.
Big file. Give it some time.
APU LCV opened at about 03.07.05 in the time line and you see a few ATS attempts following that.

We'll see what they say in the final report.

 

[ArcticFlier]

And yes, the ATS is SUPPOSED to overcome core lock, or at least that's what GE CLAIMS, and that's the heart of the lawsuit.

The pilots DID do the APU bleed air-assisted start in the correct sequence. They couldn't get core rotation on an engine that, when disassembled, showed no signs of internal damage and SHOULD have rotated freely, even though they weren't up to the restart envelope speed. At the altitude they were at during the APU assisted start, it SHOULD have at least rotated SOME (2 or 3%) but the FDR readout for both cores is absolutely ZERO after the initial upset all the way to the point of impact.

There's a problem that no one wants to talk about with that portion of the event and the engine itself.

Out of curiosity................where were the 10th stage bleed switches while they tried the restart? I'm not asking about the valve position. I know where they were. I'm asking about the switch position. Seems to me, if the APU is up, the ATS should overcome core lock. You've got decent pressure coming from the APU.

BTW.......who cares about the airstart envelope speed if you're doing an APU bleed air assist start? I haven't looked at the requirements for this lately as it's no longer a memory item (and I'm drunk enough not to get up off my ass to find it).


AF

 

[Lear70]

There's a min speed for an ATS attempt as well. I believe the switches were 10th's off / closed, apu lcv and 10th isol valve on / open. Either way, doesn't matter, as soon as you open the apu lcv, the left 10th stage closes as bleed air protection, as does the right 10th stage when you open the isol valve if the apu lcv is open.

The main problem is that it doesn't look like they went to and maintained Mach .70 until below FL 240 then stayed at 240 kts in the descent. Our company came out with a big memo reminding people of the speed requirement in the memory item again shortly after the hearing.

GE says that speed is REQUIRED to keep core airflow turning the core at least at a SMALL pace and cool the internal section enough to keep the compressor blades from expanding and contacting the side of the engine casing, thus locking it up.

GE is saying that because they didn't get and keep their speed up, that the pilots caused a problem, but won't say that core lock IS the problem they caused. Basically they're talking out both sides of their mouth, dancing around their lack of high-altitude shock-cooling testing.

 

[pilotdiscretion]

Many of the facts and analysis in this topic and the others posted about the 3701 accident are wrong. I know this because I am a member of the investigation team. For those of you who read this in an attempt to learn about the accident and learn from the crews mistakes I caution you against that. None of the investigators from this accident have or will post either facts or analysis about what happened that night. I know many people would like to know and learn from this but all I can offer you is that the NTSB final report is coming and that is the only reliable source of information to you.

 

[ArcticFlier]

The reason I asked about the 10th stage switch position is my gut feeling that APU LCV Interlock got these guys.

From the FCOM 5-10-3(stuff in () is me):

The APU compressor is also protected from a stall or surge, by interlocking the the APU LCV switch with the other bleed air switches. If the left hand 10th stage bleed air switch (not valve) is open, the APU LCV will close, or remain closed. If the 10th stage isolation valve switch and the right hand engine bleed air switch (not valve) are open, the APU LCV will close, or remain closed.

Now from the QRH, an excerpt, (granted mine is old, and I'm not sure if any changes have been made since this accident, but here's where I think the gotcha is.........I'll have to look tomorrow, when I go to work to see if the QRH's in the aircraft have been revised.):

Relight using APU bleed air:

From 13000 feet and below:
1. Target Airspeed................................Re-establish
airplane weight target best glide speed
51,000 190 kias
36,000 170 kias

2. L&R 10th stage bleed........................Closed

3. APU LCV.........................................Open

What just happened? Where are the valves positioned? Where are the 10th stage switches positioned? No where in the QRH does it say that you must press out the 10th stage switch lights. The inference is to look up and see "closed" on the switch lights (which is where the valves were).

If core lock was an issue, the ATS should have been able to overcome it, with APU bleed air. But, it didn't. Why? I remember reading something in Aviation Week (I think) regarding core lock, and GE proved time and again that the APU could restart a core locked engine.

So what happened? Hopefully we find out for sure.


AF

 

[ArcticFlier]

There's a min speed for an ATS attempt as well. I believe the switches were 10th's off / closed, apu lcv and 10th isol valve on / open. Either way, doesn't matter, as soon as you open the apu lcv, the left 10th stage closes as bleed air protection, as does the right 10th stage when you open the isol valve if the apu lcv is open.

I think you have this backwards.............it's the APU LCV that closes or remains closed if the left 10th stage is open, or the right 10th stage is open with the Isol valve open. The 10th's don't open and close based on the APU LCV. The LCV does the opening and closing.


AF

 

[PBRstreetgang]

Well,
Lessee, the 10th stage iso valves are electrically controlled and pneumatically operated. If the engine(s) are not producing any bleed air the valves fail closed and the switch and status message(s) will indicate closed. The 10th stage bleed interlock will prevent the engine from feeding 10th stage bleed air into the APU by causing the APU LCV to remain closed via switch logic. The QRH does not say to select 10th bleed switches to the closed position, it just says that they should be closed. We were taught to always mirror switch position to condition, ie 10th bleed closed, 10th stage bleed switch to the closed position. I would like to see the NTSB final report, for the final analysis.
PBR

 

[737 Pylt]

Ya, because they can walk on water, right?

Are you out of your mind?

Pull your head out and get some air.

Another 1000 hour wonder pilot telling us all how its done! Well done junior! You worry about those stalls and steep turns, thats about all you can handle!
737

 

[Tank Commander]

737 , You are an a$$. This wonder pilot wants to kick your pompous back side
all over an airport terminal. If you ever see me on a sit, PLEASE, come introduce yourself.

 

[Midge]

737 , You are an a$$. This wonder pilot wants to kick your pompous back side
all over an airport terminal. If you ever see me on a sit, PLEASE, come introduce yourself.

Hmmmm. Threats on a public forum. I see from all your previous posts that if you don't agree with someone you insult them. Way to go! If you're going to call someone an a$$, look no further than the mirror. Your signature should say own, dumba$$!

 

[Dubya]

Another 10,000 hour old fart pilot telling us all how it's done! Well done dad! You worry about those FMS's and autolands, that's about all you can handle!

W

Another 1000 hour wonder pilot telling us all how its done! Well done junior! You worry about those stalls and steep turns, thats about all you can handle!
737

 

[ReportCanoa]

Another 1000 hour wonder pilot telling us all how its done! Well done junior! You worry about those stalls and steep turns, thats about all you can handle!
737

I have flown with furloughed pilots from five different airlines. They were great to fly with, and I value their experience. I have flown with 1000 hr guys who were just as good with the airplane. I would have to say that in this situation, it was a matter of the airline hiring two individuals who did not belong in an airliner. 1000 or 6000 hours, it really wouldn't have mattered.

 

[ReportCanoa]

There's a min speed for an ATS attempt as well. I believe the switches were 10th's off / closed, apu lcv and 10th isol valve on / open. Either way, doesn't matter, as soon as you open the apu lcv, the left 10th stage closes as bleed air protection, as does the right 10th stage when you open the isol valve if the apu lcv is open.

Not always! During an APU start assist sequence, when either START switch is selected, the entire 10th stage manifold will open, regardless of switch positions. Watch it next time you are starting an engine off the APU. The logic is that if the LCV valve is open, and there is no competing air from an engine, the ISOL valve, the L & R 10th stage valves will open. The start valve on the appropriate side will also open to facilitate the start.

The interlock protection of which you speak is of course designed to prevent backflow onto the APU. It is only a factor if you have 10th stage air flowing from either or both engines. That was not the case in the accident, I do not believe as both engines were flame-out. As long as the LCV switch was selected open, the start attempt should have worked. Why the engine didn't start may as you said have been a core-lock problem.

Peace out-

 

[Tank Commander]

Hmmmm. Threats on a public forum.

Yes.

I see from all your previous posts that if you don't agree with someone you insult them.

Read what he wrote you bone head. I insult people that insult because they piss men off!

If you're going to call someone an a$$, look no further than the mirror.

Ya, if I turn around and bend over.

Your signature should say own, dumba$$!

Your the dumb a$$ for sticking up for one.

 

[FN FAL]

Ya, if I turn around and bend over.

This is NOT a "TAX" issue...not unless you guys are talking about taxing that ass.

I'm surprised this incident is still causing such a ruckus...but glad to see people are thinking.

 

[737 Pylt]

Another 10,000 hour old fart pilot telling us all how it's done! Well done dad! You worry about those FMS's and autolands, that's about all you can handle!

W

Thanks...Appreciate it, but at 37, I highly doubt I'm an old man! And if you look at my profile, the J32 (or the King Air) hardly has FMS and autoland, matter of fact, we didn't even have an auto pilot or yaw damp, but thanks for your input!
737

 

[Dubya]

So you're a 37 yr old FO mouthing off. Thats much better.

W

Thanks...Appreciate it, but at 37, I highly doubt I'm an old man! And if you look at my profile, the J32 (or the King Air) hardly has FMS and autoland, matter of fact, we didn't even have an auto pilot or yaw damp, but thanks for your input!
737

 

[737 Pylt]

So you're a 37 yr old FO mouthing off. Thats much better.

W

What's your excuse then??
737

 

[say again]

Old news! Dead horse. Learn and move on.

If it was only that easy!!! It is an accident that all pilots can learn from, unfortunately at others expense!!!

 

[Midge]

Yes

I'm pretty sure a moderator was recently banned for something such as what you did!

Read what he wrote you bone head. I insult people that insult because they piss men off!

That's right, insult me because I don't agree with you. I'm sure you are a real man's man!

Ya, if I turn around and bend over.

No doubt your best side, I'm sure you spend a lot of time bent over!

Your the dumb a$$ for sticking up for one.

That might be true. I see more intelligence from you (btw it's you're the dumba$$)! You seem to know a lot about a$$. I bet you were real popular in the showers! Have a wonderful day!

 

[737 Pylt]

You seem to know a lot about a$$.

Now that's funny!!!!!!!!!!!!
737

 

[onthestreet]

We can argue about issues such as core lock, bleed valve position, airspeeds for rotation, etc, but nothing changes the reality that aircraft have an operating envelope that needs to be respected.

If a pilot takes his aircraft outside of that envelope, he becomes a test pilot.

The crew of this flight got too slow at altitude and found themselves outside of the envelope. personally, I have a hard time blaming the manufacturer for their mistakes. Had the engine failed to start after an event that happened inside of the normal envelope, I would blame the manufacturer. But blaming Canadair or GE for this accident is akin to blaming a manufacturer for the wings coming off after after someone pulls hard enough to get past 150% of designed load.

Learn airplanes, learn how they fly and then learn to respect the fact that they will kill you if you give them a chance.

RIP to the crew, I'm sure that they did not purposely kill themselves. BTW, if the widows want to sue, they should sue the system that allowed these men to be where they were when they obviously did not have the training/knowledge/experience/judgement to be there.

 

[FN FAL]

If a pilot takes his aircraft outside of that envelope, he becomes a test pilot.

Semantically, that may be true. But in reality, that pilot becomes a negligent pilot.

I'm not pointing fingers at anyone, in any specific crash right now. And if I said I never made a mistake, I'd be the pot calling the kettle black if I did.

I'm just trying to point out that if we are going to do anything to improve safety and prevent "accidents", we must change our attitudes about what an "accident" really is.

A test pilot goes out with a clipboard and performs tests per whatever tasks are assigned to him and reports on that data. A negligent pilot ignores the risks of exceeding limitations and proceeds regardless.

If you find yourself feeling a little testily, just remember that we can only control our decisions, not the consequences of our acts. Do the right thing, fly the limitations, fly the ops manual, fly the regs and barring all of that, fly reasonable and prudent. Then, if something goes FUBAR, you'll not be found negligent should something happen.

Before retracting soap box, no...I'm not perfect, but I can choose to do the right thing on my next flight, or any flight there after and so can you.

 

[Cokie907]

10th stage switch position is ESSENTIAL when using the APU for bleed air. That is why the "Cleared to Start" checklist boxed item reads "Packs and bleeds: Set for start" The PF must look up at the overhead panel and verify the 4 white lights in a row which means left and right 10 stages switches in CLOSED position, APU LCV open and 10 stage isolation valve open.

We have had crews come in to the gate with APU shut down. They left the 10th stage switches pressed in (i.e. 10th stage valves commanded open) after shut-down. Next crew comes, starts APU and attempts to open the LCV......no bleed air. They call maintenance control and defer the APU for bleed air (assuming a LCV malfunction) and then call for a huffer start. This happened at an outstation, no kidding and I was riding in the back on a commute, during summertime and baking like a potato. Fun stuff!

 

[Flyerjosh]

Nice posts! (FN FAL & onthestreet).

 

[ArcticFlier]

Not always! During an APU start assist sequence, when either START switch is selected, the entire 10th stage manifold will open, regardless of switch positions. Watch it next time you are starting an engine off the APU. The logic is that if the LCV valve is open, and there is no competing air from an engine, the ISOL valve, the L & R 10th stage valves will open. The start valve on the appropriate side will also open to facilitate the start.

The interlock protection of which you speak is of course designed to prevent backflow onto the APU. It is only a factor if you have 10th stage air flowing from either or both engines. That was not the case in the accident, I do not believe as both engines were flame-out. As long as the LCV switch was selected open, the start attempt should have worked. Why the engine didn't start may as you said have been a core-lock problem.

Peace out-

It's switch logic...........not valve logic. If the 10th switches are "open" APU LCV interlock occurs. It has nothing to do with air flow from the 10th stage.


AF

 

[FlyBunny]

This accident is an excellent example of total unprofessionalism and poor airmanship. In addition, this accident would not have occured, in my opinion, if the FO was a furloughed legacy carrier pilot. Why? The FO would have been the leader.

Simply put, these pilots made a choice to be unprofessional. When we show up to work, we can simply choose at what level to operate.

Hhhhmmmm....'legacy carrier pilot', huh.

Like the ones who ran out fuel over near PDX (United Airlines).

Like the ones who flew the planes in to the bridge near DCA (1982).

Like the ones who decided to land in near TS in Little Rock and killed so many (AA)

Like the ones who missed the taxiway exit and continued taxiing on the runway (March 27, 1977) and caused the greatest ever number of casualties in a single accident.

Like the FedEx pilots who couldn't correct for the wind and destroyed the MD-11.

need I go on?

Fly Safe!
Bunny

 

[Rez O. Lewshun]

Hhhhmmmm....'legacy carrier pilot', huh.

Like the ones who ran out fuel over near PDX (United Airlines).

Like the ones who flew the planes in to the bridge near DCA (1982).

Like the ones who decided to land in near TS in Little Rock and killed so many (AA)

Like the ones who missed the taxiway exit and continued taxiing on the runway (March 27, 1977) and caused the greatest ever number of casualties in a single accident.

Like the FedEx pilots who couldn't correct for the wind and destroyed the MD-11.

need I go on?

Fly Safe!
Bunny

Apples to oranges. The above pilots weren't being willfully negligent. I am sure you understand the basics of the Pinancle accident. Thus, if you read my follow up post, you might not have had to post yourself.....

Here, I cut n paste for you...

The original poster was looking for info and a learning experience. As bad as this is (read embarassing) for PCL, this accident maybe the text book example of what not to do. Therefore many other operators are looking to learn from this. We can shut out the inquiries or we can be graceful and point people in the right direction. I believe the later is the professional path.

I will assume that you don't know the details of the accident, CFIT. If you do, you know then, that it was two immature pilots taking too much for granted. I used legacy carrier pilot as an example becuase the legacy flight ops culture is very old.

Usually the guys and gals that are flying at a career carrier don't have much to prove and too much to lose to operate a jet like this.. therefore they don't. It is not that legacy carrier pilots can walk on water. Perhpas I should have stated "a mature, experienced and established pilot well into his or her career" would have stopped any poor behavior and thus prevented an accident.



Regards....

 

[DoinTime]

The above pilots weren't being willfully negligent.

The above pilots may not have been willfully negligent but history is riddled with ones that were. Two that come to mind are the Northwest crew that operated drunk and the America West pilots that tried to. While these did not result in a loss of life I think you can see my point.

Its human nature to disobey rules. Being a "legacy" pilot is not an exemption to human nature.