News just reported CRJ crash...

[Freddie Spencer]

410, stall with stickshaker and dual flameout, re-lights attempted.

 

[CaptainBrazilia]

Having been on the RJ for going on two years now, I've had the thing up to 410 on a handfull of occasions. To run this thing at altitudes greater than 370, you've gotta be mindful of a lot of things, most of which have been mentioned already. One thing that hasn't been touched on (or maybe it has and I missed it) is that you need to know where you are in terms of weather. If you get up to 410 and cross a frontal zone where the ISA deviation changes significantly, you could end up having your hands full really quick...

Not speculating as to the cause of this accident...just adding to the mix of things people have presented here that could serve well in keeping us all more in the game.

Stay safe, everyone.

 

[timmay]

410, stall with stickshaker and dual flameout, re-lights attempted.

the stick shaker comes on prior to a stall it doesnt mean the airplane actually stalled. the stick pusher lowers the nose to prevent a stall from occuring.

 

[CatYaaak]

If you get up to 410 and cross a frontal zone where the ISA deviation changes significantly, you could end up having your hands full really quick...

Not speculating as to the cause of this accident...just adding to the mix of things people have presented here that could serve well in keeping us all more in the game.
QUOTE]

Not speculating either here about this case, but you've made an excellent point to always remember in general about why it can be dicey to struggle up to an altitude early, plod along, and think you're in the comfort zone just because you're burning off fuel. Our FFs in modern, smaller a/c aren't that much, and the temps can fluxuate quickly as you cross those zones. Thing can go to he11 in a handbasket in a hurry if you're high and at the edge of your perf envelope. You may quickly find yourself outside it.

And its not just temps. I remember the case of a Lear that stalled at altitude, where all it took was riding near the edge, a few bumps, and someone turning the heading bug in heading mode without using half-bank. Up there, it's possible for things to happen a lot quicker than a stick pusher can respond in time to prevent it.

 

[Freddie Spencer]

The wing actually stalled, at least according to my sources...

 

[efiscompmon]

and who might they be?

 

[Mike15601]

This has happend before in in the Corp. version of this A/C. Water in the fuel led to a double engine flameout at altitude....... Date: 20 MAR 1994
Time: 00:36 CST
Type: Canadair CL-601-3A Challenger
Operator: Crystal Aviation
Registration: N88HA
Msn / C/n: 5072
Crew: 0 fatalities / 2 on board
Passengers: 0 fatalities / 0 on board
Total: 0 fatalities / 2 on board
Airplane damage: Written off
Location: Bassett-Rock, NE (USA)
Departure airport: Burlington International Airport, VT (BTV)
Destination airport: Long Beach Municipal Airport, CA (LGB)
Narrative:
Both engines lost power at FL410; forced landing in a field, striking an irrigation structure and trees. Improper refueling by FBO personnel at Lawrence, MA caused the Challenger to depart with water contaminted fuel.

 

[lancair360]

High Alt. Engine Performance at Warmer than Std. Temps

So why make such a big deal about FL410? I still find it odd that the NTSB focused on that one issue so quickly.

I entered into the FMS the other day; FLPLN ALT = F410 with TOTAL WT = 40,000 lbs. at ISA +9 deg C and got UNABLE CRUISE ALTITUDE message. Unless you actually enter a temperature, it defaults to 0 degC which will not result in the UNABLE CRUISE ALT message.

 

[Erlanger]

Good source at Pinnacle tells me;

1) Plane stalled at 41,000' and the engines quit.

2) The plane glided 60 miles from FL41 to impact.

3) Cpt. flew, while the F.O. tryed to relight.

There's more, but I'll leave it for when it comes out in the final report,
since it wouldn't be fair to the crew and just in case the source is wrong.

 

[T-Gates]

There's more, but I'll leave it for when it comes out in the final report, since it wouldn't be fair to the crew and just in case the source is wrong.

If there is a possibility that your source is wrong, why post anything at all??

 

[Erlanger]

The 3 things I wrote above is fact and doesn't say anything about how the crew handled the situation, though I guess you could read into each one of those. The other stuff I didn't write has to do with what they did or didn't do and it can be debated all day long till we're blue in the face. We weren't there and who knows how we would handle it. The 3 things I mentioned seemed to be fact to me while the other stuff is subject to interpretation.

 

[T-Gates]

Fair enough.... I'm just trying to remain skeptical of everything until all the cards are on the table. If your source at PCL is deep within the investigation and is privy to all this information, he should know to keep his trap shut.

 

[lancair360]

Does anyone know how this cryptic FMS message UNABLE CRUISE ALT is calculated in the FMS?. Is it based upon engine peformance, aerodynamics, etc. Does UNABLE CRUISE ALT translate into a greatly increased risk of aerodynamic stall and dual engine failure in level flight?

 

[PCL_128]

It's just a digital version of the performance charts. It takes into account your weight, VNAV programmed speed, and ISA deviation to decide whether you can make it to an altitude or not.

 

[Oakum_Boy]

Also could be your TOC is beyond TOD.

 

[lancair360]

So basically, an UNABLE CRUISE ALT message is a heads up that you would need to reduce airspeed and/or rate of climb to claw your way up to FL410... i.e. you couldn't maintain both .74M and 500fpm during the entire climb per the profile. Doesn't mean you "couldn't" make it up that high though.

 

[DoinTime]

So basically, an UNABLE CRUISE ALT message is a heads up that you would need to reduce airspeed and/or rate of climb to claw your way up to FL410... i.e. you couldn't maintain both .74M and 500fpm during the entire climb per the profile. Doesn't mean you "couldn't" make it up that high though.

I believe the FMS database uses 300'/minute climb rate and the speed is adjustable in VNAV menu. The PCL performance books authorize a .70M climb speed that guarantees maneuvering at approved altitudes. A 38,000 lb CRJ will make it to just fine to FL410 at ISA temps, 300'/minute climb, and .70M.

 

[regionalcap]

I was looking at our climb chart today and 36000 was the weight limit to make it to FL410 on a ISA day.