RJ Crash Prelim

[Oakum_Boy]

That's stretching it a bit, not to mention Monday Morning Quarterbacking. There is absolutely NOTHING wrong with having this aircraft (or any other certificated for it) up at FL 41,0. To suggest that it is otherwise is to say that the manufacturer, test pilots, and FAA (not to mention the thousands of us who have safely taken the aircraft to that altitude) are somehow less knowledgeable than you are... I wouldn't go there if I were you.

Not being practical? Many times that is correct, as are the other things you mmentioned there (with the exception of TAS deteriorating - that only happens as a function of a deteriorating IAS); sometimes the conditions (weight, temperature, and available thrust) just don't make sense to stay there, but sometimes they do. Been in both situations, sometimes you stay, sometimes you gotta give it up and go lower. Same thing in the Lear up at 51,0...

Not what I was talking about! For a given Mach number, TAS decreases with altitude. Furthermore, the Mach you can achieve at high altitudes is not great. CRJ's have the best combination of performance in the high 20's:

1. They can achieve .77 mach,
2. .77 Mach at 28000 feet is much faster than .77 mach at 41000
3. CRJ-200 Can't really do .77 Mach at higher FL's.
4. Fuel burn at 28000 feet is relatively low, compared to the TAS that you can get.

Edited for spelling, and format.

 

[Mike15601]

Food for thought from a previous incident.... 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.

 

[Lear70]

Mike, the info you posted had been up on another thread, but fuel contamination doesn't seem to be a factor here... lots of reasons why, but the main one is that during the double engine failure, the right one got so hot that it damaged it (probably so badly that it wouldn't have restarted), which means (more than likely) that the fuel going in was burning just fine (too much fuel, not enough cooling air = extreme high temp).

Oakum, the generalities you posted on Mach .77 only work if you assume a TP level of 28,0. As long as temperature continues to decrease with altitude, a constant mach number will result in a higher TAS with a higher altitude. It only stops doing that when the ambient lapse rate stops.

And Mach .77 at 41,0? H*ll, we're lucky to get .70 out of the thing that high. Our standard cruise speed is .74, and although I'd be trying to go MUCH faster to have the airflow over the wing (resultant lift) to get higher, it may have bled off to .74 or .70 to get that last 4,000 feet but we'll know more in a month or so about that.

I personally like FL 31,0 and 33,0 in this aircraft for the best combination of fuel burn and TAS, and she'll do .77 all day long at those altitudes if you keep her speed up in the climb.

 

[acaTerry]

You mean Mr. Red FAce? Yes it is if we are thinking of the same guy

 

[comrcap]

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!

 

[efiscompmon]

Of course, Express I refused all offers of technical assistance and acquired knowledge from CMR (both CMR mgmt and Alpa) when we got our jets in 2000. Better to go it alone with our memphian inferiority complex and re-invent the wheel with our FSI manuals. I have never been privy to a min speed limitation--boy would I be peeved if that is a contributing factor in this investigation.

Can't help but wonder if SAFETY could have been enhanced by chatting with the world's largest operator of the type. I'll put that SQUARELY on Jon Y. and Santi L.'s shoulders.

I wonder how much the new "fuel policy" had an effect on the decision to be at 410.

So let's review--incomplete training, knowledge transfer blocked by management arrogance, intimidation in flight planning and fuel burn. Sounds like pinch-a-nickle! No wonder Phil T. is the RAA apologist of the year. These muppets couldnt manage a bake sale.

The irony here is that SOC is _still_ trying to dx illegally with questionable performance. "Hey, I know it's 8C and precip; would you consider taking off without anti-ice so we can make our numbers?"
"Uhhh. No. It's a limitation."
"No, it's a switch, just switch it off Captain."
Friggin unbelievable. Would be funny if people weren't dead.

I think Aaron says it best with the company motto of "Never Compromise Savings!"

 

[Oakum_Boy]

.
As long as temperature continues to decrease with altitude, a constant mach number will result in a higher TAS with a higher altitude. It only stops doing that when the ambient lapse rate stops.

Not trying to start anything here, but lets talk about this. If you're flying a constant Mach#, your TAS DECREASES with altitude. For example, if you're flying Mach 1 at sea level, that means your TAS equals the speed of sound, which at sea level is 761 MPH. Now, go to FL410. Mach 1 at 410 is 660 miles per hour. Above the Tropopause, ambient lapse rate stops, yes. But, warmer temperatures will require an increase of thrust to attain a particular Mach number. That's why above it, jets don't perform as well in terms of fuel flow. I think you're thinking of constant IAS which with altitude results in higher TAS. If fly with some people who think that's the way Mach works because the only example, unless you've been schooled properly, is when climbing at a constant IAS, then trasitioning to Mach. Until you transition to Mach, your TAS is increasing with altitude. Should I be scared when an experienced jet driver doesn't know this?????? Anyone care to jump in on this subject?????

 

[Lear70]

Oakum, no need to get personal or combative, your "Should I be scared..." comment is uncalled for.

I disagree with your assertion, but we'll put your theory to the test in ACTUAL flying conditions when I start my two-day this afternoon.

 

[DirkkDiggler]

I disagree with your assertion, but we'll put your theory to the test in ACTUAL flying conditions when I start my two-day this afternoon.

It's not an assertion. It's a fact. You can look it up an any flying book that talks about high performance jet aircraft. You guys need to read some books so you'll understand a bit more about the things you deal with everyday at work.

 

[Oakum_Boy]

Oakum, no need to get personal or combative, your "Should I be scared..." comment is uncalled for.

I disagree with your assertion, but we'll put your theory to the test in ACTUAL flying conditions when I start my two-day this afternoon.

Yes, it was uncalled for. Sorry.