RJ Crash Prelim

[jetflyer]

What I'm trying to say is that a HOT START is very likely at FL 410 I would think.

Say it took them 1 minute before they could begin the DOUBLE ENGINE FAILURE MEMORY ITEMS. At that point you'd basically, when you turn on the CONT IGNITION at that altitude if the engines had already spun down, be attempting a WINDMILL start with too low an airspeed.

Jet

 

[DirkkDiggler]

Jetflyer,


I'd say you've got a pretty decent theory as to why the engine may have had some heat damage. I don't know if that's what happened but at least it's a possible scenario. Thank god. Someone on this board has a brain, and uses it too. I was giving up hope.

 

[jetflyer]

Thanks Dirk, LOL.

 

[jetflyer]

Dirk,

It possibly may have been the reason they had to do the forced landing as well.

Haven't we all been wondering: Why couldn't they get the engines restarted??

We've all been sitting back thinking that we'd have been able to do the QRH procedures and get the engines restarted with no problem. MAYBE NOT.

A windmill start is a crazy procedure. You're not even supposed to begin it until FL 210 in the CRJ50. The QRH says you will even lose about 5000 ft at the required 330 kts.

My theory is and it's only a theory:
1) One minute or MORE passed after double engine failure occured before the DOUBLE ENGINE FAILURE memory items were begun.
2) With the engines having already spun down now, turning on the CONTINUOUS IGNITION is ESSENTIALLY a WINDMILL START at:
a) too low an engine speed
b) too low an aircraft speed
c) too high an altitude with very thin air
3) Under these conditions and GIVING FIRE TO FUEL, a HOT START COULD occur VERY VERY QUICKLY, if the thrust levers are not brought back to SHUT OFF. If they were only brought back to IDLE the HOT START would have continued.
4) If a HOT START happened this could have left them with USELESS ENGINES and making a forced landing of great importance.
5) This is maybe why they had to give up restart attempts and had to ask where the nearest airport was.

ALL MY OPINION and SORRY FOR THE SPECULATION. I'm trying to see if I can figure out how to handle this in the future to save me and my passenger's lives.

Jet

 

[DirkkDiggler]

Of course, that's assuming that they didn't to the memory items for a double engine failure immediately. I can't say whether they did but I can certainly see how easy it would be lose your train of thought given all the chaos that would be going on all at once.

 

[jetflyer]

Dirk I agree,

Losing your train of thought would BE VERY EASY to see with losing both engines.

When starting the CF34-3B1 engines we're supposed to wait till atleast 20% N2 on the ground.

Say turning on the Continuous Ignition was delayed by one minute:
Them turning on the Continuous ignition like they are SUPPOSED TO DO right after a double engine failure BUT with a slow engine speed where the engines have already spun down and with the very thin air up at FL 410 would have been about the EQUIVALENCY in MY OPINION OF:

1) Bringing the thrust levers to IDLE during an engine start at about 2-3% N2 at SEA LEVEL. <---Which would always cause a HOT START

Jet

 

[DirkkDiggler]

Not if they put the ignition on immediately as you're supposed to do from memory after a double engine failure. The N2 does spin down but there's plenty of time to get the ignition on while they're still spinning fast enough.

 

[jetflyer]

Yea,

I'm not saying this is what happened but it could have, I guess.

These would have all been happening:
MASTER CAUTION and WARNING flashing
bells and whistles going off
the AIR DRIVEN GENERATOR popping out of the nose making all sorts of noise,
and losing pressurization slowly
loss of some of the screens in the RJ till the ADG kicked in
a possible stick shaker and PUSHER if the nose was not IMMEDIATELY lowered because of the bleeding off of the airspeed very quickly with no engines.
Maybe having to don oxygen masks.
A ton of other things could have been going on and it was DARK the whole time.

Not to mention the immediate thoughts through their heads:
Oh Schnit!
I'm gonna be fired.
I'm gonna possibly not live.
ETC.

We're all told to slow down in these scenarios and not rush to judgement. I think almost all of us would have been delayed by trying to keep the plane from stall/spinning and being extremely overwhelmed that hitting that CONTINUOUS IGNITION button may have been delayed or not even IMMEDIATELY thought of.

Jet

 

[DirkkDiggler]

I agree.

 

[saabingitagain]

I don't think a hot start would cause obvious external heat damage. The hot start would take place in the combustor and be contained there. I have had GEs go hot.. real hot.. over 1000c in the blink of an eye.. no damage.. just an inspection and a lot of po'ed pax.