RJ Crash Prelim

[DiverDriver]

Sorry Hmmm, you're wrong. The speeds listed on those charts are not limiting. If the manufacturer wanted to put in place a minimum climb speed, they would have made it a limitation. They wouldn't have buried it in a climb chart. The climb charts are used as a reference to determine what altitude you can get to and your time to get there. They do not give us a minimum climb speed.

Well, by virtue of their being a "profile" listed with those climb numbers it does kind of make it a "limitation". If you don't climb at that profile (speed) then you won't make these numbers work. Kind of backdoor way of approach it but...

 

[Lear70]

Lear70, You worry me. It has nothing to do with this unfortunate accident and I'm not interested in agreeing or disagreeing with you various theories. You're jumping all over 172driver and reminding him of all your experience, and the number of jets you've flown as captain.

Well Surplus, you "worry", or more to the point, ANNOY and IRRITATE pretty much everyone on this board depending on the thread you choose to invade, so forgive me if your post doesn't upset me too terribly much.

If you look more closely at the way this entire divergence of the thread started, you will plainly see that it began with a few people starting to question my ability to command based on whether I had forgotten that TAS decreased with altitude at a constant Mach. The bashing began THERE, I simply replied in kind and pointed out that with their experience they could keep their opinions to themselves, as can you.

Hmmm, don't be sayin' I'm teachin' people to fly anything OTHER than the PUBLISHED PROFILES, 128 didn't say that. I agree with you that the speed profiles are limiting, simply because I talked with Terry and Parker a few years ago about those speeds, specifically that when we're heavy climbing at 290 to .74 and we're heavy, the speed will bleed off, but if you keep your speed up at 320 to .77 it does a much better job.

They told me I could fly any published profile I liked, but it better be ONE of the three profiles. If it wasn't and something happened, it could be the basis for company job action and as some in the Association present pointed out, there would be no MEC recourse to get someone's job back if they were operating outside the published profiles and something happened.

 

[hmmm]

Lear70 My dear fellow poster. I did not say you were teaching him wrong. Read my post more clearly and slowly. I know you may be reading these posts on one of those mobile internet cards between flights.

I said he should go back and talk to you since he may have misunderstood you when he (PCL128) said that we have no speed limitation.

I agree with what you just said and had the same talks with some of the good ol boys. And you know what the flight plan is based on in that it is written on the front page of the release. It says "Flight Plan Based on: Best Burn".

Leave that up to the beholder to interpret which "climb profile" determined by "oprational requirements" meets the requirements of "Best Burn" that the Flight Plan is based on.

 

[Lear70]

You might have misunderstood what he was teaching.

That's where I got that... and despite popular opinion I'm not so big a computer geek as to have one of those mobile internet cards, I leave that to "Arive".

 

[PCL_128]

After having a conversation with Hmmm on a few PMs, I wanted to clarify a few things. Hmmm seems to think that I was implying it was normal and OK to fly outside of profile. That's not what I meant at all. Anyone that has flown with me knows that I always fly profile unless ATC requests something different. Profiles are there for a reason and should be followed.

Hmmm was also worried that I was implying that the pilots of the crashed aircraft were flying below .70. I never said that, and I want to make that perfectly clear. I don't have any idea what speed they were flying and neither does anyone else outside of the investigation.

My point has always been that there is nothing in the limitations section of our FCOM that states a minimum climb speed. I stand by that statement. I'm not saying that you should fly slower than profile, I'm just saying that we don't have a specific minimum climb speed listed as a limitation that some other RJ operators have in their books.

I hope that clears things up.

 

[hmmm]

Good job the way you wrote that 128


Mean Old Son of a Bia'tch.

 

[J Dawg]

We have a limitation in our CRJs that states we need to have at least one pack on (10th stage) or cowl anti-ice (14th stage) on at those altitudes. The reason is by having a demand on the 10th or 14th stage pneumatic systems, a vacuum is created as air is drawn into the appropriate duct work. This vacuum helps draw air into the engines at high altitudes (and its resulting high angle of attack), which in turn helps them operate normally.

The fact that the engines need this kind of help from the pneumatic system at FL410 scares me.

As far as fuel efficiency goes, according to my textbooks, the most efficient altitude for a turbofan is about 36,000. Above this altitude, the RATE of decrease in density is far more greater than the rate of temperature decrease. Therefore an engine's thrust will decrease with an increase in altitude. To maintain thrust, more power (fuel) must be added.

Also, any fuel savings created by having a longer flight idle descent are negated by having the engines firewalled for the longer climb.

As far as the CRJ being a climb pig at high altitudes, it is more because of the wing than the engines. The highly swept wing was designed to go fast (low drag), not generate a lot of lift (high drag).

We all have our own personal quirks about flying. For the above reasons, one of mine is to never go above FL370 in a CRJ. No reason to.

 

[tin kicker]

We have a limitation in our CRJs that states we need to have at least one pack on (10th stage) or cowl anti-ice (14th stage) on at those altitudes.

Is this in the Pinnacle FCOM? I have not been able to find it. Could someone point me to the right page?

Thanks

 

[another cfii]

As far as I know, 1 pack in operation above FL 250, nothing about the cowl anti-ice.

 

[J Dawg]

Is this in the Pinnacle FCOM? I have not been able to find it. Could someone point me to the right page?

Thanks

The limitation I quoted comes from the Atlantic Coast (operating as FLYi) CL-65 FSM.

 

[Russ]

Though not well known those also apply at SkyWest.

 

[Relic01]

Those apply for Mesa as well.

 

[Lear70]

Absolutely it's a Pinnacle limitation as well.

FCOM 2, OL-10, right under engine operating limits:

NOTE: If above 40,000 feet, one air-conditioning unit or cowl anti-ice must be selected on for each engine.

 

[WhiteCloud]

Continued CRJ Crash discussion

My guess is that they stalled the airplane and both engines flamed out. The rj-50 is a pig at FL410, even if empty. That is why Comair has a min speed limitation (climb) for our rj's. We've had a couple of incidents a while ago where the aircraft was allowed to go below the green line and get on the back side of the power curve. Stick shaker and all the rest. No flame out though, thank god!

I was thinking the same thing. Is the angle of attack at FL410 high enough that the air flow through the engines is disrupted?

 

[jetflyer]

Question

I DON'T KNOW THIS IS WHY I AM ASKING THIS:


The investigators said the right engine was severely heat damaged correct? This worries me because the last thing any of us would want to happen in a double engine failure is accidentally damage the engines.
This could have happened from any number of scenarios. It COULD have happened from a relight attempt gone wrong. But could it have happened from the scenario I'm about to propose??


Say that right after the double engine failure, the double engine failure MEMORIZATION items are not immediately done.

For the CRJ: Continuous Ignition on and then if the engines don't relight bring the thrust levers back to shutoff, and on and on.

WHAT WOULD HAPPEN IF:
The engines are not brought back to shutoff immediately?

A WINDMILL START attempt in the CRJ calls for a speed of around 330 knots with ignition on and then bring the thrust levers out of shutoff. You're trying to spin up the engines fast enough for the start essentially.

If the ENGINES ARE NOT BROUGHT back after the double engine failure but the THRUST LEVERS ARE STILL AT CLOSE TO FULL POWER for a minute or two, wouldn't this essentially be an UNINTENTIONAL WINDMILL START without enough SPEED??

COULD THIS OVERHEAT THE ENGINES dumping all this fuel in the engines without enough airflow??

I DON'T KNOW that's why I'm asking. Could someone politely tell me if I'm right or WHY I AM MOST CERTAINLY WRONG because no one else has mentioned this.
Please no one get crazy about me asking this, I just am trying to figure out for my own piece of mind if this scenario happens to me how I can get the engines lit safely and prevent damaging them.

Jet

 

[DirkkDiggler]

I would say that you are accurate that in the above scenario, a lot of fuel is being dumped into the engines. However, after a flame-out, there is no more flame inside the engine to ignite that fuel. The only way to get the fuel to light is to turn the continuous ignition on. So unless the continuous ignition were on, the fuel would just be pissing out the back of the engines. If anyone disagrees, please educate me.

 

[jetflyer]

Dirk,
Thanks for replying so fast. I didn't think about there not being a flame. You're right. Thanks. How about this then:

SAY DOUBLE ENGINE FAILURE OCCURS:
You'd be losing pressurization, get 20-30+ Cautions and Warning lights. The ADG would be popping out, making things very loud. If the NOSE were not IMMEDIATELY LOWERED, the plane would most likely get a stick shaker, then PUSHER, because airspeed would degrade very quickly.

SAY 3 MINUTES HAVE PASSED BY, fuel has been pumping in the engines like crazy all this time, then the MEMORIZATION ITEMS ARE BEGAN.

FIRST MEMORY ITEM: Continuous Ignition ON.

What would happen then I wonder?? Could they almost immediately overheat the engines after turning on the continuous ignition if a couple minutes have passed by and ALL THAT FUEL HAS BEEN PUMPING IN THE ENGINES before the CONTINOUS IGNITION is turned on??

Again I don't know that's why I'm asking. But if this were the case and the engines wouldn't overheat till the CONTINUOUS IGNITION were turned on, they HOPEFULLY could catch the OVERHEAT in time and bring the thrust levers to shutoff before damage could occur.


Jet

 

[jetflyer]

I thought about this some more. The fuel would be pissing out the back of the engines like you said Dirk so a build up of fuel would not occur.

BUT IF THE CONTINUOUS IGNITION were turned on and because the speed would only be about .70 mach for a glide at that altitude, it would be essentially like a WINDMILL START with not enough speed. The RELIGHT ATTEMPT for the windmill start is not even supposed to be attempted until below FL 210 in the CRJ, so at FL 410, I would think the air would not be dense enough for a restart anyways.

So if they turned the Continuous ignition on LIKE THE MEMORY ITEMS SAY, the engines most likely WOULD NOT RESTART but would immediately begin to overheat.
If the engines had ALREADY CONTINUED TO WIND DOWN to almost nothing I would think an OVERHEAT and HOT START would be VERY LIKELY, VERY QUICKLY.
They would have to do number TWO in the MEMORY ITEMS pretty quickly at that altitude I would think:
2) THRUST LEVERS--SHUTOFF

If the thrust levers were not brought back quick enough after the Continuous ignition was brought on with too low an airspeed and TOO LOW AN ENGINE SPEED at SUCH A HIGH ALTITUDE damage WOULD OCCUR ALMOST IMMEDIATELY CORRECT??
This would leave any future relight attempts probably USELESS if the engines were already severely heat damaged, leaving a forced landing as the only option.

SORRY FOR ALL THE SPECULTAION. Just trying to see if I can figure out how to prevent such a HORRIFIC TRAGEDY from happening to me in the future. Thank you guys.

Jet

 

[Freddie Spencer]

So if they turned the Continuous ignition on LIKE THE MEMORY ITEMS SAY, the engines most likely WOULD NOT RESTART but would immediately begin to overheat

Overheat from CONT only? Don't think so pal..

BTW, "overheat:" sounds like you are jappin about Chevy -89 van with a busted radiator

 

[jetflyer]

Hey Freddie,


NO NOT ONLY THE CONTINUOUS IGNITION. You'd have fuel.

The ignition does what to fuel? Ignites it right?
If the engine speed is not fast enough you get fire but no operating engine, giving you a HOT START.

Jet