Jefferson City pilots took plane to maximum altitude

[Bucky]

http://news.yahoo.com/s/ap/plane_crash_investigation

I think this was reported a month ago as well, but there was another
round of news releases today stating that the pilots took their
Bombardier CJR200 to its maximum altitude of 41,000 ft. Afterwards,
both engines failed and they crashed before reaching an airport.

Of course, the pilots should not have experimented around, but is it
dangerous to take a plane to its max altitude? When the engineers
specify a maximum altitude, doesn't it still have to be safe at that
altitude?

[Larry Dighera]

On 13 Jun 2005 14:13:27 -0700, "Bucky" > wrote in
. com>::

>http://news.yahoo.com/s/ap/plane_crash_investigation
>

>Of course, the pilots should not have experimented around,

You sound like this spokesman from the Air Travelers Association:

David Stempler, president of the Air Travelers Association, said
the issue may be reckless pilots rather than inadequate training
or improper recovery procedures.

"This is more a story of pilots having time on their hands and
playing with things in the cockpit that they shouldn't," he said.

Flying, he said, is as boring as truck driving most of the time.

"This was boredom and experimentation, these guys experimenting
with things they had no business doing," Stempler said.

>but is it dangerous to take a plane to its max altitude?

If the FAA certified the aircraft for a 'service ceiling' of 41,000',
it should operate nominally at that altitude.

>When the engineers specify a maximum altitude, doesn't it still have
>to be safe at that altitude?

Without a specific definition of the meaning of 'maximum altitude' in
this case it's difficult to know.

[Michael 182]

"Bucky" > wrote in message
oups.com...
> http://news.yahoo.com/s/ap/plane_crash_investigation
>

> Of course, the pilots should not have experimented around, but is it
> dangerous to take a plane to its max altitude? When the engineers
> specify a maximum altitude, doesn't it still have to be safe at that
> altitude?
>

The head of the Air Travelers Association also blames the pilots. "This is
more a story of pilots having time on their hands and playing with things in
the cockpit that they shouldn't," ... "Flying, is as boring as truck driving
most of the time. This was boredom and experimentation, these guys
experimenting with things they had no business doing," Stempler said.

How is it that pilots have no business flying a plane to it's ceiling? Seems
like pretty reasonable behavior to me.

Michael

[Bucky]

Larry Dighera wrote:
> You sound like this spokesman from the Air Travelers Association

Yeah, that's because I borrowed his words. I only presented that side
of the argument so that it would be represented and people would not
further bring up that aspect. I just wanted to focus on what "maximum
altitude" means. Do planes carrying passengers ever fly at their
maximum operating altitude? Or is that considered too risky?

> Without a specific definition of the meaning of 'maximum altitude' in
> this case it's difficult to know.

Straight from the official technical specs:

http://www.bombardier.com/index.jsp?id=3_0&lang=en&file=/en/3_0/3_1/3_1_1_1_3_5.html

Ceiling: Maximum operating altitude 41,000 ft

[Bucky]

Michael 182 wrote:
> The head of the Air Travelers Association also blames the pilots.
> How is it that pilots have no business flying a plane to it's ceiling? Seems
> like pretty reasonable behavior to me.

I'm not blaming the pilots. I just want to find out if flying a plane
at its maxmimum operating altitude is standard practice, or if it's
considered dangerous.

For example, the top speed of a car could be 120 mph, but it would be
dangerous to drive it at that speed because a sudden movement in the
steering wheel could cause the car to flip over.

[Bob Gardner]

Maximum altitude is usually based on pressure differential...the difference
between ambient pressure outside the aircraft vs cabin pressure...the
engines don't come into the equation. I have had a Lear 23 up to FL43, which
is/was its maximum altitude. The Lear's manual contained a restart envelope,
just in case one or both engines failed...it involved gliding down to at
least 12000 feet before a restart was attempted (the atmosphere must contain
enough oxygen to support combustion).

Bob Gardner

"Bucky" > wrote in message
oups.com...
> http://news.yahoo.com/s/ap/plane_crash_investigation
>
> I think this was reported a month ago as well, but there was another
> round of news releases today stating that the pilots took their
> Bombardier CJR200 to its maximum altitude of 41,000 ft. Afterwards,
> both engines failed and they crashed before reaching an airport.
>
> Of course, the pilots should not have experimented around, but is it
> dangerous to take a plane to its max altitude? When the engineers
> specify a maximum altitude, doesn't it still have to be safe at that
> altitude?
>

[Mike Rapoport]

"Bucky" > wrote in message
oups.com...
> Michael 182 wrote:
>> The head of the Air Travelers Association also blames the pilots.
>> How is it that pilots have no business flying a plane to it's ceiling?
>> Seems
>> like pretty reasonable behavior to me.
>
> I'm not blaming the pilots. I just want to find out if flying a plane
> at its maxmimum operating altitude is standard practice, or if it's
> considered dangerous.
>
> For example, the top speed of a car could be 120 mph, but it would be
> dangerous to drive it at that speed because a sudden movement in the
> steering wheel could cause the car to flip over.
>

Obviously you have never driven your car 120mph.

Mike
MU-2

[Matt Whiting]

Bucky wrote:

> Michael 182 wrote:
>
>>The head of the Air Travelers Association also blames the pilots.
>>How is it that pilots have no business flying a plane to it's ceiling? Seems
>>like pretty reasonable behavior to me.
>
>
> I'm not blaming the pilots. I just want to find out if flying a plane
> at its maxmimum operating altitude is standard practice, or if it's
> considered dangerous.
>
> For example, the top speed of a car could be 120 mph, but it would be
> dangerous to drive it at that speed because a sudden movement in the
> steering wheel could cause the car to flip over.
>

It is only dangerous if the driver is stupid. Stupidity is always
dangerous.


Matt

[Bucky]

Bob Gardner wrote:
> Maximum altitude is usually based on pressure differential...the difference
> between ambient pressure outside the aircraft vs cabin pressure...the
> engines don't come into the equation.

So you're saying that the engines could operate at an even higher
altitude. It's just that the cabin pressure could not be maintained?

[Paul Tomblin]

In a previous article, "Bucky" > said:
>I'm not blaming the pilots. I just want to find out if flying a plane
>at its maxmimum operating altitude is standard practice, or if it's

It's called "operating" altitude for a reason.


--
Paul Tomblin > http://xcski.com/blogs/pt/
"An appointment is an engagement to see someone, while a morningstar is a
large lump of metal used for viciously crushing skulls. It is important not
to confuse the two, isn't it, Mr. --?" - Terry Pratchett

[Michelle P]

I have been in one on my old employers CRJ-200s at 41000 feet and I can
tell you they fly fine. We we repositioning and want to get home. I
un-fortunately was riding in the jump seat and not the left seat. :-(
Michelle

Bucky wrote:

>http://news.yahoo.com/s/ap/plane_crash_investigation
>
>I think this was reported a month ago as well, but there was another
>round of news releases today stating that the pilots took their
>Bombardier CJR200 to its maximum altitude of 41,000 ft. Afterwards,
>both engines failed and they crashed before reaching an airport.
>
>Of course, the pilots should not have experimented around, but is it
>dangerous to take a plane to its max altitude? When the engineers
>specify a maximum altitude, doesn't it still have to be safe at that
>altitude?
>
>
>

[Bob Gardner]

No. A pressurized airplane is like a balloon....more pressure inside than
out. If the pressure differential overcomes all of the safety features meant
to avoid such a disaster, there would be a blowout at the weakest
point...maybe a window, maybe a door seal, who knows? OTOH, if "cabin
pressure could not be maintained" means an explosive decompression to you,
then your statement would be correct.

What it would take to keep the fire burning in the engines is something else
again...there has to be a point at which combustion fails. Obviously, the
two fun-seekers lost their engines. Neither you nor I know why. I can't
understand the restart problem, though.

An aspect of max altitude that has not been mentioned here is the "coffin
corner" where Mach buffet and stall speed come together. Nothing to do with
engine failure, but a consideration when flying high.

Bob Gardner

"Bucky" > wrote in message
oups.com...
> Bob Gardner wrote:
>> Maximum altitude is usually based on pressure differential...the
>> difference
>> between ambient pressure outside the aircraft vs cabin pressure...the
>> engines don't come into the equation.
>
> So you're saying that the engines could operate at an even higher
> altitude. It's just that the cabin pressure could not be maintained?
>

[John Galban]

Bucky wrote:
>
> For example, the top speed of a car could be 120 mph, but it would be
> dangerous to drive it at that speed because a sudden movement in the
> steering wheel could cause the car to flip over.

This can happen at 75 mph or at 50 mph. What's so magic about 120
mph? If you're point is that driving a car is dangerous, I agree. If
you're trying to make some analogous connection to flying a plane at
it's service ceiling, you missed the boat (car, plane...).

John Galban=====>N4BQ (PA28-180)

[Peter Duniho]

"Bucky" > wrote in message
oups.com...
> I'm not blaming the pilots. I just want to find out if flying a plane
> at its maxmimum operating altitude is standard practice, or if it's
> considered dangerous.

It's not considered dangerous.

> For example, the top speed of a car could be 120 mph, but it would be
> dangerous to drive it at that speed because a sudden movement in the
> steering wheel could cause the car to flip over.

A sudden movement in the steering wheel could cause the car to flip over at
60 mph, depending on the nature of the movement (which would be true at 120
mph as well). Likewise, an airplane can be crashed from practically any
altitude or airspeed.

Even with your reference, it's not clear what is meant by "maximum
altitude", but assuming that marketing document is referring to the
certified ceiling of the aircraft (as described on the type certificate),
the aircraft should be expected to fly safely all the way up to, and
including, that altitude. This would include expecting the engine design to
tolerate operation at that altitude, without stoppage.

I can see no justification for expecting the pilots to limit themselves to a
lower altitude. The CVR may indicate a less-than-professional approach to
their flying (one normally selects a cruise altitude for reasons other than
entertainment, for example :) ), but there's no indication that they did
anything wrong operationally.

Of course the article says nothing about whether they stopped at 41,000'.
It sure sounds as though they got to FL410, and then just cruised at that
altitude. But if they had tried to climb higher, that might have presented
a problem. Until there's evidence they did so, however, the "head of the
Air Travelers Association" has no basis for his comments. All
experimentation had presumably been done previously, during the
certification of the airplane. All the pilots were doing is operating the
airplane within the limits determined during certification.

It will be interesting to see what the ultimate determination of the engine
failures is. It could be one of at least three causes, including:

* Pilots exceeded certified ceiling (ie they didn't stop climbing at
41,000')

* Poor maintenance resulted in engines that no longer performed to
certified standards

* Erroneous or (even worse) fraudulent data used during certification
resulting in an aircraft that had never actually been tested at the designed
and certified ceiling of 41,000'

It may turn out to be something else entirely.

Perhaps when the final NTSB report is released, information along those
lines will be provided. Until then, I think it's premature for anyone to be
criticizing any party, the pilots or otherwise, for any liability in the
accident. It could even turn out that, in the end, it was all just an
accident.

Pete

[Peter Duniho]

"Bucky" > wrote in message
oups.com...
> So you're saying that the engines could operate at an even higher
> altitude. It's just that the cabin pressure could not be maintained?

It really just depends on the aircraft. Every airplane has a variety of
limits with respect to their operation. For many of those limits, there are
actually a variety of potential limiting factors resulting in those limits,
with usually only one being the *actual* limiting factor.

For a pressurized aircraft, the certified ceiling could be due to the
pressurization system or due to some engine limitations, or due to something
else entirely (like stall speed, for example, where "stall" refers to an
aerodynamic limitation having nothing to do with the engines). You'd have
to consult the aircraft designer to learn which it was.

Pete

[Bob Moore]

"Bob Gardner" wrote
> An aspect of max altitude that has not been mentioned here is the
> "coffin corner" where Mach buffet and stall speed come together.
> Nothing to do with engine failure, but a consideration when flying
> high.

True..and "coffin corner" is weight dependant.
The 41,000' limit for the B-707 was determined by
the time required to execute an emergency descent
to 14,000'.

Bob Moore

[Kyle Boatright]

"Bucky" > wrote in message
oups.com...
> http://news.yahoo.com/s/ap/plane_crash_investigation
>
> I think this was reported a month ago as well, but there was another
> round of news releases today stating that the pilots took their
> Bombardier CJR200 to its maximum altitude of 41,000 ft. Afterwards,
> both engines failed and they crashed before reaching an airport.
>
> Of course, the pilots should not have experimented around, but is it
> dangerous to take a plane to its max altitude? When the engineers
> specify a maximum altitude, doesn't it still have to be safe at that
> altitude?

When an aircraft's operating limitats are established, the idea is that you
should be able to safely operate the aircraft within those limitations.
Exceed the limitats beyond a certain safety factor, and bad things may
happen.

The question I have not seen answered is whether 41,000' is outside the
normal operating limits for the aircraft, particularly for its engines. If
so, these guys were playing test pilot, if not, there was nothing wrong,
foolish, dangerous, careless, or irresponsible with taking the aircraft to
that altitude.

KB

[[email protected]]

The reason these engines failed is MORE COMPLICATED than the fact they
were at 41,000'. These planes can fly at 41,000'. What happened is
related to how they got to 41,000'. They got there by exceeding the
maximum climb rate. The plane was empty so it climbed very fast. But
due to some complicated factors, the engines cannot go to that altitude
that fast. They overheated. This was a published limitation. They
exceeded it. Even my simple explanation is not adquate as it is more
complicated than this. This is due to the fact that I don't completely
understand it either.

And to answer your question, yes it is safe to operate at max altitude,
if the pilot follows all of the correct procedures when operating the
plane and if the plane does not have damage and has been maintained
correctly etc. The plane has been tested there, and higher still, so
there is some safety factor.

These engine failures were from some complicating factors. Not just as
simple as flying too high.

One word of advice. Don't get your accurate information from the
newspapers. You have to go deeper to get accurate information.

[Kyle Boatright]

"Kyle Boatright" > wrote in message
...
>
> "Bucky" > wrote in message
> oups.com...
>> http://news.yahoo.com/s/ap/plane_crash_investigation
>>
>> I think this was reported a month ago as well, but there was another
>> round of news releases today stating that the pilots took their
>> Bombardier CJR200 to its maximum altitude of 41,000 ft. Afterwards,
>> both engines failed and they crashed before reaching an airport.
>>
>> Of course, the pilots should not have experimented around, but is it
>> dangerous to take a plane to its max altitude? When the engineers
>> specify a maximum altitude, doesn't it still have to be safe at that
>> altitude?
>
> When an aircraft's operating limitats are established, the idea is that
> you should be able to safely operate the aircraft within those
> limitations. Exceed the limitats beyond a certain safety factor, and bad
> things may happen.
>
> The question I have not seen answered is whether 41,000' is outside the
> normal operating limits for the aircraft, particularly for its engines.
> If so, these guys were playing test pilot, if not, there was nothing
> wrong, foolish, dangerous, careless, or irresponsible with taking the
> aircraft to that altitude.
>
> KB

My apologies. I made a too-quick correction and changed limitations to
limitats, instead of limits...

[Bob Gardner]

Not to drag this out any further than necessary, but searching Part 25 for
maximum altitude gets me two hits, both dealing with pressurization.
Searching for maximum certificated altitude gets one hit, dealing with
electrical systems.

Bob Gardner

> wrote in message
oups.com...
> The reason these engines failed is MORE COMPLICATED than the fact they
> were at 41,000'. These planes can fly at 41,000'. What happened is
> related to how they got to 41,000'. They got there by exceeding the
> maximum climb rate. The plane was empty so it climbed very fast. But
> due to some complicated factors, the engines cannot go to that altitude
> that fast. They overheated. This was a published limitation. They
> exceeded it. Even my simple explanation is not adquate as it is more
> complicated than this. This is due to the fact that I don't completely
> understand it either.
>
> And to answer your question, yes it is safe to operate at max altitude,
> if the pilot follows all of the correct procedures when operating the
> plane and if the plane does not have damage and has been maintained
> correctly etc. The plane has been tested there, and higher still, so
> there is some safety factor.
>
> These engine failures were from some complicating factors. Not just as
> simple as flying too high.
>
> One word of advice. Don't get your accurate information from the
> newspapers. You have to go deeper to get accurate information.
>

[Peter Duniho]

> wrote in message
oups.com...
> The reason these engines failed is MORE COMPLICATED than the fact they
> were at 41,000'. These planes can fly at 41,000'. What happened is
> related to how they got to 41,000'. They got there by exceeding the
> maximum climb rate.

Interesting theory. Please share with us where you obtained that
information.

Your theory seems the most plausible of anything I've heard, but the NTSB
hasn't released the final report, nor have I seen any specific information
about the climb they executed. Do you actually have a reference for your
statement, or are you just guessing?

Pete

[Doug]

Well, the idea behind this theory is this. Engines burn fuel. Fuel
causes heat. Heat needs to be dissipated into the air (air btw, is the
only place it can ultimately go). As you climb there is less air. Heat
that was made with the more dense air some time ago needs to be
dissipated by less dense air now. Less dense air cannot dissipate as
much heat. Get the picture? We see steady state example of this in
overheating turbocharged piston engines that can be pushed too hard at
altitude. This climbing one is a little more complicated because it
involves changing air density, but same basic idea. The heat collects
in the engine. The cooling is designed for air density only so much
less than the air density that made the heat. Exceed that and you
overheat. The overheated engines seized. Climb at the rate the engine
is designed for and this wont happen. Could only climb that fast
because they were empty.

It's just a theory so far as what CAUSED the accident, but this
behavior is well known.

[Jose]

> Heat that was made with the
> more dense air some time ago needs to be
> dissipated by less dense air now. [...]

> The cooling is designed for air density only so much
> less than the air density that made the heat.

I didn't realize that heat remembered how it was made.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain."
(chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

[Dave Butler]

wrote:

> One word of advice. Don't get your accurate information from the
> newspapers. You have to go deeper to get accurate information.

....like say, from usenet. ;-)

[Bob Moore]

"Doug" wrote
> It's just a theory so far as what CAUSED the accident, but this
> behavior is well known.

From my initial training in jet powered aircraft (T-2V) in 1959
during Navy flight training to my retirement from flying jet
powered aircraft (B-727) at PanAn in 1991, I have never heard
of this theory nor experienced its effects. And, I can assure
you that the small B-720 with the big B-707 engines when empty
climbed like a rocket to 41,000'.

Sure sounds to me like a simple case of not enough fuel pressure
from the tanks to feed the engine driven pumps. This could be
caused by various reasons from failure to use the tank mounted
boost system to operating below the fuel freeze point allowing the
fuel filters to become obstructed.

A couple of web sites with items of interest:

http://www.tfec6.org/Download/invited/JKLee.pdf

http://www.geocities.com/fchemical/1.html
At extremely low temperature a fuel may have a high viscosity.
Although a boosted pump is use to deliver fuel to the engine,
the oil feed to this pump from the oil tank is by gravity and
it is essential that it should not be impeded by too high viscosity
fuel with final boiling points below 300oC generally have
viscosities sufficiently low for them to flow to the pump its
temperatures down to their freezing point. The limiting temperature
of use would be determine by solidification of the fuel in the tanks,
and this would not occur until well below the freezing point, firstly,
because the freezing point is the temperature at which solid being to
separate under arbitrary test conditions and not the temperature at
which the fuel solidifies and secondly because of mechanical agitation
inherent in the system. In practice therefore the specification of a
maximum freezing point corresponding to the lowest service temperature.
Likely to be experienced provides an ample margin of safety. A maximum
freezing point of -40oC or -60oC, according to the type of the service,
ensures adequate flow under all practical conditions including starting
at very low temperatures.

I'm putting my money on wrong fuel (freeze point) for the existing OAT.

Bob Moore
ATP B-707 B-727 B-720
PanAm (retired)

[Doug]

What kind of engines did the aircraft on the Jefferson City flight
have? What kind of engines are on the Boeings that Bob flew?

[Bob Moore]

"Doug" wrote
> What kind of engines did the aircraft on the Jefferson City flight
> have? What kind of engines are on the Boeings that Bob flew?

What kind of experience/training do you have?

Bob Moore

[Wolfgang Kemper]

John Galban wrote:
>
> Bucky wrote:
>
>>For example, the top speed of a car could be 120 mph, but it would be
>>dangerous to drive it at that speed because a sudden movement in the
>>steering wheel could cause the car to flip over.
>
>
> This can happen at 75 mph or at 50 mph. What's so magic about 120
> mph? If you're point is that driving a car is dangerous, I agree. If
> you're trying to make some analogous connection to flying a plane at
> it's service ceiling, you missed the boat (car, plane...).
>
> John Galban=====>N4BQ (PA28-180)
>
Little notice from a German "Autobahn" driver:
I had a Alfa Romeo where I felt very comfortable even with 150 mph
and I had a Jaguar where 120mph was nice but at 150mph I had the
impression to became instable.
I pushed a Chevy Blazer to 100 mph and was afraid to kill myself.
Everything is relative , some dudes manage to flip over at 30mph , I
have seen this last December here in Dallas, and with the right car and
environment even 200 mph are safe.

Sorry way OT.

[Guy Elden Jr]

Engine out issues aside, one thing that struck me about this accident
was the fact that these guys had so much altitude in which to glide to
a safe landing that I wonder if it was actually _too_ much altitude? I
don't know how far away the airport was that they finally decided upon
for the emergency landing attempt, but clearly they didn't succeed in
meeting their goal. Were they too complacent in thinking they'd be able
to restart the engines, given that they were nearly 8 miles up?

One of the things I always try to get on a long x-country in a 172SP is
altitude. I've only flown on the east coast of the U.S. during my short
3 years as a private pilot, and while there are lots of airports
around, there are stretches where I'd be out of gliding range from an
airport even at 10,000 feet. These guys had 4 times that, and still
couldn't make it to an airport. Was there a field that was closer and
still suitable enough for their plane to land on? Considering they were
in a no-power situation, I assume on short final they'd be coming in
pretty close to stall speed to minimize forward velocity when touching
down (tho maybe I'm wrong on that point). I just can't believe that
with all that altitude they couldn't get safely on the ground.

--
Guy

[Mike Rapoport]

> wrote in message
oups.com...
> The reason these engines failed is MORE COMPLICATED than the fact they
> were at 41,000'. These planes can fly at 41,000'. What happened is
> related to how they got to 41,000'. They got there by exceeding the
> maximum climb rate. The plane was empty so it climbed very fast. But
> due to some complicated factors, the engines cannot go to that altitude
> that fast. They overheated. This was a published limitation. They
> exceeded it. Even my simple explanation is not adquate as it is more
> complicated than this. This is due to the fact that I don't completely
> understand it either.
>
> And to answer your question, yes it is safe to operate at max altitude,
> if the pilot follows all of the correct procedures when operating the
> plane and if the plane does not have damage and has been maintained
> correctly etc. The plane has been tested there, and higher still, so
> there is some safety factor.
>
> These engine failures were from some complicating factors. Not just as
> simple as flying too high.
>

Where do you come up with this BS? There is no relationship between climb
rate and over temping.

Mike
MU-2

[Mike Rapoport]

"Doug" > wrote in message
ups.com...
> What kind of engines did the aircraft on the Jefferson City flight
> have? What kind of engines are on the Boeings that Bob flew?
>

Gas Turbine Engines.

Mike
MU-2

[Doug]

Mike,
Yes, Gas Turbine Engines. But what design, what manufacturer?
Different airplanes and different engines behave differently.

But think about it. Heat gets generated at lower altitude. There is a
thermal lag. That heat gets dissipated at higher altitude. If you are
climbing VERY fast, the incoming air is less dense, you can set up a
cycle where heat is accumulating faster than it can be transferred due
to the denser air creating more combustion. Sort of like having an
extra boost of turbo charging. With the slower airspeed in a climb, and
if the engine is operating close to the edge of it's heat dissipation
maximum, it COULD cause overheating. Anyway, you see my point, I hope.
(Even if it is wrong in this case).

But I will yield, as I have no supporting data. The supporting data
would be a climb limitation in the manufacturers flight manual. I don't
have it, but I am sure it exists. These internet arguments are never
won anyway. I'm not really interested in winning. Probably should have
worded my initial statement a little less concretely. I honestly
thought this was the cause. Apparently not, or at least not sure yet,
or not public yet. Whatever.

It's just my theory. Sorry about the two pilots dying. That is a tough
one for the families I am sure. Whatever the reason is, I am sure we
all want it found out so that other pilots and passengers can benefit
from the knowledge.

Airline travel is very safe, statistically, by the way. But you already
know that.

Sorry if I ruffled any feathers..

[Bob Moore]

"Doug" wrote
> But think about it. Heat gets generated at lower altitude. There is a
> thermal lag. That heat gets dissipated at higher altitude. If you are
> climbing VERY fast, the incoming air is less dense, you can set up a
> cycle where heat is accumulating faster than it can be transferred due
> to the denser air creating more combustion. Sort of like having an
> extra boost of turbo charging. With the slower airspeed in a climb, and
> if the engine is operating close to the edge of it's heat dissipation
> maximum, it COULD cause overheating. Anyway, you see my point, I hope.
> (Even if it is wrong in this case).

Young man...you don't have the foggiest idea about the operation
of aircraft jet engines.

Bob Moore

[[email protected]]

Bob,

This one certainly has me curious as to the cause. I've got very
limited experience in fanjets, but I've flown them at max operating
altitude and consider it a normal operation. In the turbojet 20-series
Lears we regularly went to FL450 in the 23 and 24B (usually after one
hour of flight) to get the fuel burns as low as possible when hauling
freight (plus, back then, there was nobody up that high and we always
got direct). In one version of the 25 we could go to FL510 although
even when very light, the climb rate going through 490 was so slow we
wondered whether we'd make 510 before time to start down (and, as you
know, you could see the curvature of the earth).

I did lose an engine at FL450 in a 24B when the captain moved the power
levers fairly quickly and an old fuel control unit couldn't handle it
at that altitude, flaming out the engine. We got a relight at 17,000
although, as I recall, the relight envelope was supposed to go to
25,000 (let's just say maintenance at that organization was not exactly
top notch - long out of business).

As a result, I'm curious as to what would cause both engines to go
quiet - the only common system is fuel, although I don't know the CRJ
systems at all and wonder whether there is/are any procedure(s) that
must be followed above a certain altitude regarding pumps or if the
company regularly flew so low that they didn't put in any additives
such as PRIST to prevent ice in the fuel. Have to contact a CRJ
captain friend of mine and see what she says. Also wondering why the
relight was unsuccessful...just doesn't make sense, jet engines are so
darn simple in operation - add fuel, ignite and go. Also wondering why
they couldn't make an airport from 410 in central Missouri.

The overheating comment on this thread is laughable. And I thought I'd
heard all of the nutty theories of aircraft accidents. Or maybe it was
some localized heavy gravity that shortened the glide range....

Your thoughts?

Warmest regards,
Rick

[Bob Moore]

wrote
> or if the company regularly flew so low that they didn't put
> in any additives such as PRIST to prevent ice in the fuel.

That is what I suspect. In the Boeing jetliners, we didn't use
the additives (too expensive), but we did have fuel heaters on
the main filters to keep them from "waxing" over. A "one minute"
shot of hot bleed air every 30 minutes usually did the trick,
however I have had to reduce the cruise altitude and increase
the mach number to keep the tank boost pumps operating.

Bob Moore

[Peter Duniho]

"Bob Moore" > wrote in message
. 122...
> [...]
> I'm putting my money on wrong fuel (freeze point) for the existing OAT.

I think the climb rate theory has been sufficiently disputed. However, I
find the thought that outside air temperature at FL410 might be an issue,
when (presumably) the airplane was being operated safely at a lower altitude
AT THE EXACT SAME TEMPERATURE, pretty silly too.

I don't know the exact altitude of the tropopause on the day of the
accident. But it was likely in the neighborhood of FL300 give or take a few
thousand feet. From the tropopause all the way up to FL410 (and higher),
the temperature would have been a relatively constant -57 C.

Sorry...that theory doesn't pass the sniff test any more than the "overtemp
due to climb" theory does. Not unless your theory is claiming that the
altitude the pilots climbed to was entirely irrelevant, and that the
accident would have happened regardless (I would find that to be a
reasonable inclusion in the theory, though it would beg the question as to
why other planes didn't have similar troubles that day, since the fuel
presumably sold to a wide variety of aircraft was apparently not suitable
for high-altitude flight).

Pete

[Mike Rapoport]

"Doug" > wrote in message
oups.com...
> Mike,
> Yes, Gas Turbine Engines. But what design, what manufacturer?
> Different airplanes and different engines behave differently.
>
> But think about it. Heat gets generated at lower altitude. There is a
> thermal lag. That heat gets dissipated at higher altitude. If you are
> climbing VERY fast, the incoming air is less dense, you can set up a
> cycle where heat is accumulating faster than it can be transferred due
> to the denser air creating more combustion. Sort of like having an
> extra boost of turbo charging. With the slower airspeed in a climb, and
> if the engine is operating close to the edge of it's heat dissipation
> maximum, it COULD cause overheating. Anyway, you see my point, I hope.
> (Even if it is wrong in this case).
>
> But I will yield, as I have no supporting data. The supporting data
> would be a climb limitation in the manufacturers flight manual. I don't
> have it, but I am sure it exists. These internet arguments are never
> won anyway. I'm not really interested in winning. Probably should have
> worded my initial statement a little less concretely. I honestly
> thought this was the cause. Apparently not, or at least not sure yet,
> or not public yet. Whatever.
>
> It's just my theory. Sorry about the two pilots dying. That is a tough
> one for the families I am sure. Whatever the reason is, I am sure we
> all want it found out so that other pilots and passengers can benefit
> from the knowledge.
>
> Airline travel is very safe, statistically, by the way. But you already
> know that.
>
> Sorry if I ruffled any feathers..


Frankly the overtemping due to climb theory is ridiculous and it doesn't
matter what gas turbine engines you are talking about. The fuel controllers
constantly sample inlet air temp and pressure along with the pressure at the
compressor discharge and trim the fuel flow to prevent the hot section
temperature from changing without power lever movement. More sophisticated
fuel controllers will allow the temp to rise with decreasing mass flow to
the temperature limit (or one of several limits) while keeping some other
parameter constant (like N1, fan rpm) then trim the fuel flow back to avoid
over temping the hot section. In any case it is fuel flow (ie mixture) that
determines temperature and the fuel controller is not going to be fooled by
climbing fast.

You are thinking about the problem like you would a piston engine.
Limiting turbine engine temperatures are analogous to EGT on a piston
engine, they are *not* analagous to CHT on a piston engine. It is a
function of fuel flow which is constantly monitored and adjusted by the fuel
controller...ie a *mixture* issue not a cooling issue.

Mike
MU-2

[Montblack]

("Guy Elden Jr" wrote)
[snip]
> Engine out issues aside, one thing that struck me about this accident
> was the fact that these guys had so much altitude in which to glide to
> a safe landing that I wonder if it was actually _too_ much altitude? I
> don't know how far away the airport was that they finally decided upon
> for the emergency landing attempt, but clearly they didn't succeed in
> meeting their goal. Were they too complacent in thinking they'd be able
> to restart the engines, given that they were nearly 8 miles up?


My thoughts exactly.

10:1 = 80 miles
15:1 = 120 miles

I wonder if they had x-length of runway as a landing requirement set in
their minds? Or, like that person in the Everglades, with a rough running
engine a month ago, heading for a patch of freeway - then diverting to an
airport that ATC advised, even though he wasn't sure if he could make it if
the engine quit. (It worked out for him)

I wonder if they had no ATC to advise them, would they have chosen to put it
down at a smaller (closer) 3,000-ft strip airport? Or, maybe they were ok
with the chosen field, but did some math wrong in their heads, and didn't
catch it until too late. Very sad.

Also, has 'no fuel' been ruled out? I might have missed that part.


Montblack

[Bob Moore]

"Peter Duniho" wrote
> I think the climb rate theory has been sufficiently disputed.
> However, I find the thought that outside air temperature at FL410
> might be an issue, when (presumably) the airplane was being operated
> safely at a lower altitude AT THE EXACT SAME TEMPERATURE, pretty silly
> too.

Maybe cold soaking...as often happened to me

> Sorry...that theory doesn't pass the sniff test any more than the
> "overtemp due to climb" theory does. Not unless your theory is
> claiming that the altitude the pilots climbed to was entirely
> irrelevant, and that the accident would have happened regardless (I
> would find that to be a reasonable inclusion in the theory, though it
> would beg the question as to why other planes didn't have similar
> troubles that day, since the fuel presumably sold to a wide variety of
> aircraft was apparently not suitable for high-altitude flight).

The predicted temp at cruise altitude determined the type of fuel
to be loaded...Jet A, Jet B, Kero A-1, or JP-4. I have had to
alter the cruise altitude due to the type of fuel that had been
previously loaded.

Bob Moore

[Peter Duniho]

"Bob Moore" > wrote in message
. 122...
> Maybe cold soaking...as often happened to me

That would not depend on the altitude however. In fact, if anything, "cold
soaking" would be more of a problem at a lower altitude, since there is more
thermodynamic mass to absorb heat from the airplane (and thus the fuel).

> The predicted temp at cruise altitude determined the type of fuel
> to be loaded...Jet A, Jet B, Kero A-1, or JP-4. I have had to
> alter the cruise altitude due to the type of fuel that had been
> previously loaded.

Thank you for that clarification. That does reinforce my understanding that
fuel temperature is unlikely to have been causal in this accident. That is,
there's no suggestion that the planned cruise altitude was low enough for a
"high temperature" fuel to have been loaded. Any cruise altitude even
moderately into the flight levels would require "low temperature" fuel (I
apologize for the generic terms...I don't know which types have what
temperature ratings).

Of course, without knowing the planned cruise altitude for certain, I can't
rule out the fuel theory. It could have been that the flight was originally
planned at a relatively low altitude. One thing your theory has going for
it is that it might explain the difficulty in restarting the engines, since
the fuel might not have had time to warm up enough during the glide,
especially assuming the temperatures would have remained too cold to do any
good for most of the glide anyway.

In any case, until such specifics are released, I still don't think that
speculation is likely to come up with much useful data. :) The NTSB should
be able to provide us with some real answers at some point, once they've had
enough time to sift through all of the facts.

Pete

[Skywise]

Wolfgang Kemper > wrote in news:d8mpdd$ent$1
@home.itg.ti.com:

> John Galban wrote:
>>
>> Bucky wrote:
>>
>>>For example, the top speed of a car could be 120 mph, but it would be
>>>dangerous to drive it at that speed because a sudden movement in the
>>>steering wheel could cause the car to flip over.
>>
>>
>> This can happen at 75 mph or at 50 mph. What's so magic about 120
>> mph? If you're point is that driving a car is dangerous, I agree. If
>> you're trying to make some analogous connection to flying a plane at
>> it's service ceiling, you missed the boat (car, plane...).
>>
>> John Galban=====>N4BQ (PA28-180)
>>
> Little notice from a German "Autobahn" driver:
> I had a Alfa Romeo where I felt very comfortable even with 150 mph
> and I had a Jaguar where 120mph was nice but at 150mph I had the
> impression to became instable.
> I pushed a Chevy Blazer to 100 mph and was afraid to kill myself.
> Everything is relative , some dudes manage to flip over at 30mph , I
> have seen this last December here in Dallas, and with the right car and
> environment even 200 mph are safe.
>
> Sorry way OT.

I agree. It all depends on the vehicle, the driver, and probably
more importantly, the road conditions.

I have a Harley Sportster ('86 883) and I've pushed it over the
century mark. On a good clean road it's rock solid. Then again,
I've been nearly dumped by a railroad crossing in bad shape at
only 30mph. Damn near jolted the handle bars out of my hands.

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism

Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Blog: http://www.skywise711.com/Blog

Sed quis custodiet ipsos Custodes?

[Mike Rapoport]

"Peter Duniho" > wrote in message
...
> "Bob Moore" > wrote in message
> . 122...
>> Maybe cold soaking...as often happened to me
>
> That would not depend on the altitude however. In fact, if anything,
> "cold soaking" would be more of a problem at a lower altitude, since there
> is more thermodynamic mass to absorb heat from the airplane (and thus the
> fuel).
>
>> The predicted temp at cruise altitude determined the type of fuel
>> to be loaded...Jet A, Jet B, Kero A-1, or JP-4. I have had to
>> alter the cruise altitude due to the type of fuel that had been
>> previously loaded.
>
> Thank you for that clarification. That does reinforce my understanding
> that fuel temperature is unlikely to have been causal in this accident.
> That is, there's no suggestion that the planned cruise altitude was low
> enough for a "high temperature" fuel to have been loaded. Any cruise
> altitude even moderately into the flight levels would require "low
> temperature" fuel (I apologize for the generic terms...I don't know which
> types have what temperature ratings).
>
> Of course, without knowing the planned cruise altitude for certain, I
> can't rule out the fuel theory. It could have been that the flight was
> originally planned at a relatively low altitude. One thing your theory
> has going for it is that it might explain the difficulty in restarting the
> engines, since the fuel might not have had time to warm up enough during
> the glide, especially assuming the temperatures would have remained too
> cold to do any good for most of the glide anyway.
>
> In any case, until such specifics are released, I still don't think that
> speculation is likely to come up with much useful data. :) The NTSB
> should be able to provide us with some real answers at some point, once
> they've had enough time to sift through all of the facts.
>
> Pete
>

Keep in mind that it takes a long time to cool fuel in the wing. The top of
the fuel is not even touching the skin after a small portion is burned off
and the fuel does not contact the leading edge either. The fuel with the
highest gel point (Jet A) is still good to below -40C (well below if memory
serves me correctly. Fuel gelling is a problem in long range aircraft or
aircraft that have been on the ramp in Thule in Jan. for a couple of days.
I would be surprised if it applied in this case. There just wasn't enough
time for the fuel to cool sufficiently.

Mike
MU-2

[[email protected]]

Mike,

It's been so darn long since I flew at 410 and above, however, I do
recall that we had to use PRIST in the Lears all the time to prevent
the entrained or suspended moisture in the fuel from freezing and then
clogging filters. Fuel gelling was never a problem.

That's why I'm wondering if the cause wasn't frozen moisture in the
fuel plugging filters and starving the engines, which would also tend
to prevent a restart under those conditions. Any thoughts?

All the best,
Rick

[Doug]

Here is another clue:
http://www.ntsb.gov/events/2005/Pinnacle/exhibits/314036.pdf

And, like I said. I really don't know either.

[Morgans]

"Mike Rapoport" > wrote

>
> Where do you come up with this BS? There is no relationship between climb
> rate and over temping.

Would the possibility of overheating exist from the fuel controller being
inaccurate at altitudes over 36,000 feet, as the manufacturer of the
aircraft has just warned?
--
Jim in NC

[Doug]

Yeah, gotta stop thinking climb rate and start thinking climb SPEED.
If you don't climb at enough speed, bad things can happen. (But climb
speed is related to rate of climb to some extent, so maybe not so far
off).

[Mike Rapoport]

Water in the fuel certainly could have been the problem but it would be
surprising if any problem with the fuel only affected one airplane. I know
that on my airplane, the first thing to suspect when a fuel filter bypass
light illuminates is ice crystals in the fuel filter and an immediate
descent is indicated.

Mike
MU-2


> wrote in message
oups.com...
> Mike,
>
> It's been so darn long since I flew at 410 and above, however, I do
> recall that we had to use PRIST in the Lears all the time to prevent
> the entrained or suspended moisture in the fuel from freezing and then
> clogging filters. Fuel gelling was never a problem.
>
> That's why I'm wondering if the cause wasn't frozen moisture in the
> fuel plugging filters and starving the engines, which would also tend
> to prevent a restart under those conditions. Any thoughts?
>
> All the best,
> Rick
>

[Mike Rapoport]

"Morgans" > wrote in message
...
>
> "Mike Rapoport" > wrote
>
>>
>> Where do you come up with this BS? There is no relationship between
>> climb
>> rate and over temping.
>
> Would the possibility of overheating exist from the fuel controller being
> inaccurate at altitudes over 36,000 feet, as the manufacturer of the
> aircraft has just warned?
> --
> Jim in NC
>

Sure, but this is unrelated to clilmb rate.

Mike
MU-2

[Jose]

I'm inclined to wonder if the pressurization or oxygen system was
working properly. From what I have read, the actions of the pilots
subsequent to engine failure were not very... er... enlightened, and
make me suspect hypoxia.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain."
(chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

[Arketip]

Mike Rapoport wrote:
> "Peter Duniho" > wrote in message
> ...
>
>>"Bob Moore" > wrote in message
. 122...
>>
>>>Maybe cold soaking...as often happened to me
>>
>>That would not depend on the altitude however. In fact, if anything,
>>"cold soaking" would be more of a problem at a lower altitude, since there
>>is more thermodynamic mass to absorb heat from the airplane (and thus the
>>fuel).
>>
>>
>>>The predicted temp at cruise altitude determined the type of fuel
>>>to be loaded...Jet A, Jet B, Kero A-1, or JP-4. I have had to
>>>alter the cruise altitude due to the type of fuel that had been
>>>previously loaded.
>>
>>Thank you for that clarification. That does reinforce my understanding
>>that fuel temperature is unlikely to have been causal in this accident.
>>That is, there's no suggestion that the planned cruise altitude was low
>>enough for a "high temperature" fuel to have been loaded. Any cruise
>>altitude even moderately into the flight levels would require "low
>>temperature" fuel (I apologize for the generic terms...I don't know which
>>types have what temperature ratings).
>>
>>Of course, without knowing the planned cruise altitude for certain, I
>>can't rule out the fuel theory. It could have been that the flight was
>>originally planned at a relatively low altitude. One thing your theory
>>has going for it is that it might explain the difficulty in restarting the
>>engines, since the fuel might not have had time to warm up enough during
>>the glide, especially assuming the temperatures would have remained too
>>cold to do any good for most of the glide anyway.
>>
>>In any case, until such specifics are released, I still don't think that
>>speculation is likely to come up with much useful data. :) The NTSB
>>should be able to provide us with some real answers at some point, once
>>they've had enough time to sift through all of the facts.
>>
>>Pete
>>
>
>
> Keep in mind that it takes a long time to cool fuel in the wing. The top of
> the fuel is not even touching the skin after a small portion is burned off
> and the fuel does not contact the leading edge either. The fuel with the
> highest gel point (Jet A) is still good to below -40C (well below if memory
> serves me correctly. Fuel gelling is a problem in long range aircraft or
> aircraft that have been on the ramp in Thule in Jan. for a couple of days.
> I would be surprised if it applied in this case. There just wasn't enough
> time for the fuel to cool sufficiently.
>
> Mike
> MU-2
>
>
You are correct Mike, fuel takes hours to cool to even close to freezing
point

[Doug]

>Where do you come up with this BS? There is no relationship between climb
>rate and over temping.

>Mike
>MU-2

Well never mind where I got it initially, but it's all on the NTSB
website now. There are even the cockpit data recorder info online. They
are looking at climb SPEED (they climbed for 15 minutes at slower than
the speed called for in the manual, which is in one of the files on the
NTSB website), they STALLED the aircraft at 41k (or so). They failed to
do a restart. And they are looking at seized engines. It doesn't
actually say yet, the engines seized, but they have some reports on
engine core lock in the display documents. There is a rather gripping,
blow by blow transcription of everything the pilots and ATC said, as
well as their struggle to unsuccessfully restart the engines. They
aren't looking at fuel or pressurization issues.

If you want to actually find out what happened check it out at:
http://www.ntsb.gov/events/2005/Pinnacle/exhibits/

The idea about the cooling "cycle" (getting behind the cooling curve),
is not there yet and I didn't see engine temperatures in the data
recording file. Don't know why. There may be more coming out on that
one. Maybe not. Anyway, if the engines DID seize, both of them, there
is something peculiar going on with the GE engines, probably related to
the speed at which they climbed. But this is all preliminary and
obviously not conclusive. This one is going to be interesting.

[[email protected]]

Bob,

Word on the street now is that it may have been something called "core
lockup" on both engines. Bombardier claims it's never happened on an
in-service engine, however.

More here:
http://www.ntsb.gov/events/2005/Pinnacle/exhibits/323843.pdf

All the best,
Rick

[Peter Duniho]

> wrote in message
oups.com...
> Word on the street now is that it may have been something called "core
> lockup" on both engines. Bombardier claims it's never happened on an
> in-service engine, however.
>
> More here:
> http://www.ntsb.gov/events/2005/Pinnacle/exhibits/323843.pdf

If I read that right (and I'm not sure I did), "core lockup" is something
that happens to an engine that has been stopped. That is, it's not a cause
of engine stoppage, but rather it's a cause of not being able to restart the
engine once it's been stopped. Something else needs to stop the engine
first (eg in their testing, they shut down the engine and let it spool down,
and THEN test for "core lockup").

Pete

[Peter Duniho]

"T o d d P a t t i s t" > wrote in message
...
> [...]
> I'm not familiar with how these engines react at high
> altitude/high AOA, but I presume that shutdown is one
> possible consequence since the AOA sensor automatically
> turns on continuous ignition at high alpha. Anyone want to
> comment?

Well, I'm no expert either. But my understanding is that high angles of
attack can result in a compressor stall, resulting in loss of combustion,
thus the automatic operation of the ignition system.

Jose made the comment that he wondered if hypoxia wasn't playing a part in
this. After reading the transcript, I can certainly see where he got that
idea. The pilots seem relatively oblivious to what's going on, they fail to
immediately start flying to a safe landing site (which IMHO is the very
first action after any engine failure), and they spend WAY too much time
trying to restart the engines, rather than planning for an emergency
landing.

One other thing I noticed was that the one pilot was several times
commenting on maintaining their airspeed at 170 knots, leading me to believe
the airspeed wasn't very high. The "core lockup" article suggests that
slowing to 190 knots may be sufficient to reduce engine rotation completely.
If so, the pilots in this accident were WAY too slow to ensure the engines
didn't stop rotating, and should have flown at a MUCH higher airspeed during
the glide.

I assume that somewhere in the flight data recorder information is airspeed
information, but I don't have time to look at it right now.

All that said, this definitely appears to be one of those accidents where
there were several links in the chain leading to the accident, or at least
the fatalities. One key link was the failure to divert to an airport
immediately upon engine failure. Had they done so, I think all of the other
issues would have been academic, and we would have the two people who could
actually answer questions directly about what happened still alive.

Pete

[Mike Rapoport]

"Doug" > wrote in message
ups.com...
> >Where do you come up with this BS? There is no relationship between
> >climb
>>rate and over temping.
>
>>Mike
>>MU-2
>
> Well never mind where I got it initially, but it's all on the NTSB
> website now. There are even the cockpit data recorder info online. They
> are looking at climb SPEED (they climbed for 15 minutes at slower than
> the speed called for in the manual, which is in one of the files on the
> NTSB website), they STALLED the aircraft at 41k (or so). They failed to
> do a restart. And they are looking at seized engines. It doesn't
> actually say yet, the engines seized, but they have some reports on
> engine core lock in the display documents. There is a rather gripping,
> blow by blow transcription of everything the pilots and ATC said, as
> well as their struggle to unsuccessfully restart the engines. They
> aren't looking at fuel or pressurization issues.
>
> If you want to actually find out what happened check it out at:
> http://www.ntsb.gov/events/2005/Pinnacle/exhibits/
>
> The idea about the cooling "cycle" (getting behind the cooling curve),
> is not there yet and I didn't see engine temperatures in the data
> recording file. Don't know why. There may be more coming out on that
> one. Maybe not. Anyway, if the engines DID seize, both of them, there
> is something peculiar going on with the GE engines, probably related to
> the speed at which they climbed. But this is all preliminary and
> obviously not conclusive. This one is going to be interesting.
>

OK that is totally different. Forward speed while climbing in a turbine
aircraft near max altitude is critical not only because of l/d but also
becasue turbine engines produce more power as higher airspeeds as inlet
pressure is higher. Sounds like the pilots of this aircraft operated
outside the airplanes flight envelope and then were unfortunate enough to
have the engines sieze after they flamed out.

Mike
MU-2

[Chris]

"Mike Rapoport" > wrote in message
ink.net...
>
> "Doug" > wrote in message
> ups.com...
>> >Where do you come up with this BS? There is no relationship between
>> >climb
>>>rate and over temping.
>>
>>>Mike
>>>MU-2
>>
>> Well never mind where I got it initially, but it's all on the NTSB
>> website now. There are even the cockpit data recorder info online. They
>> are looking at climb SPEED (they climbed for 15 minutes at slower than
>> the speed called for in the manual, which is in one of the files on the
>> NTSB website), they STALLED the aircraft at 41k (or so). They failed to
>> do a restart. And they are looking at seized engines. It doesn't
>> actually say yet, the engines seized, but they have some reports on
>> engine core lock in the display documents. There is a rather gripping,
>> blow by blow transcription of everything the pilots and ATC said, as
>> well as their struggle to unsuccessfully restart the engines. They
>> aren't looking at fuel or pressurization issues.
>>
>> If you want to actually find out what happened check it out at:
>> http://www.ntsb.gov/events/2005/Pinnacle/exhibits/
>>
>> The idea about the cooling "cycle" (getting behind the cooling curve),
>> is not there yet and I didn't see engine temperatures in the data
>> recording file. Don't know why. There may be more coming out on that
>> one. Maybe not. Anyway, if the engines DID seize, both of them, there
>> is something peculiar going on with the GE engines, probably related to
>> the speed at which they climbed. But this is all preliminary and
>> obviously not conclusive. This one is going to be interesting.
>>
>
> OK that is totally different. Forward speed while climbing in a turbine
> aircraft near max altitude is critical not only because of l/d but also
> becasue turbine engines produce more power as higher airspeeds as inlet
> pressure is higher. Sounds like the pilots of this aircraft operated
> outside the airplanes flight envelope and then were unfortunate enough to
> have the engines sieze after they flamed out.

Darwinism at work again

[Montblack]

("Mike Rapoport" wrote)
> OK that is totally different. Forward speed while climbing in a turbine
> aircraft near max altitude is critical not only because of l/d but also
> becasue turbine engines produce more power as higher airspeeds as inlet
> pressure is higher. Sounds like the pilots of this aircraft operated
> outside the airplanes flight envelope and then were unfortunate enough to
> have the engines sieze after they flamed out.


The Salt Lake Tribune:
http://www.sltrib.com/business/ci_2800743
Excerpts from conversations between Pinnacle Airlines Capt. Jesse Rhodes and
First Officer Peter Cesarz just before they died in the crash of a
Bombardier regional jet on Oct. 14, 2004.

Thursday's AvWeb:
<http://www.avweb.com/eletter/archives/avflash/414-full.html#189978>
(scroll down for it)

....And The High Price Of A Good Time

"Aw [expletive] we're gonna hit houses, dude." The NTSB has released new
information -- including cockpit voice excerpts (see NewsWire) -- related to
the Oct. 14 fatal crash of a Pinnacle Airlines regional jet. The pilots were
flying an empty Bombardier CL-600-2B19 and hoping to "have a little fun"
when they decided to climb to the jet's maximum altitude at FL410, according
to transcripts from the Cockpit Voice Recorder (CVR) that the NTSB released
this week. The two were ferrying the 50-seat jet from Little Rock, Ark., to
Minneapolis on Oct. 14. A controller questioned the jet's model and altitude
told the pilots, "I've never seen you guys up at 41 there." The crew
responded, "Yeah, we're actually ... we don't have any passengers on board,
so we decided to have a little fun and come up here." Minutes later, the
pilots told controllers first that one and later that both engines had
failed. An automatic system had attempted to lower the nose as the aircraft
lost airspeed at 41,000 feet, but the pilots overrode it. The plane stalled
and turbulent airflow entered the engines, according to NTSB information
obtained by the New York Times. Though the NTSB noted that the aircraft had
been within gliding distance of five suitable airports when the pilots were
first aware of the loss of power, the aircraft did not make a runway. The
pilots had attempted, but were unable, to restart either engine and crashed
more than two miles short of Jefferson City, Mo., airport. They missed the
houses.

Both pilots were killed when the aircraft crashed in a residential
neighborhood at night -- excerpts from their last exchanges suggest they
were trying for a road. According to an NTSB report quoted in The New York
Times, "Investigators formed the impression that there was a sense of allure
to some pilots to cruise at FL 410 just to say they had 'been there and done
that.'" The airline has blamed the pilots for behaving unprofessionally and
disregarding their training. The Air Line Pilots Association has said the
airline's training program was inadequate and that the engines suffered
"core lock" caused by differential cooling when engines are run at high
thrust and suddenly shut down -- an allegation the manufacturer has
rejected. The FAA issued, June 2, a Special Airworthiness Information
Bulletin intended to clarify and promote successful air-restart procedures
in the case of a double engine failure. According to NTSB data, "starter
assist" is required to start engines at altitudes below 15,000 feet and
speeds below 190 knots. The NTSB will investigate whether the aircraft's GE
engines indeed suffered core lock and whether proper technique could have
seen them restarted. Investigative exhibit items from the public docket are
available here.

<http://www.ntsb.gov/events/2005/Pinnacle/exhibits/>


Montblack

[Dave S]

Bucky wrote:
When the engineers
> specify a maximum altitude, doesn't it still have to be safe at that
> altitude?
>
Remember, at above 18,000 feet your altimeter is set to 29.92. The
airplane continues to perform and behave based on density altitude. How
much of a difference that is (between PA and DA) up at FL410.. I have no
idea.

In this case, the in the course of trying to obtain max altitude (or
maybe even climb higher) they got too slow. And stalled. Any airplane
will stall given the right circumstances. The autopilot/aircraft systems
tried to correct the situation (by pushing the stick forward, to cause a
descent) and the pilots (incorrectly) chose to override a properly
functioning safety feature.

In this particular stall evolution, the engines both failed because the
smooth airflow going into the engines that were operating at high
power/high flow was disrupted, and for whatever reason they were unable
to restart the engines. There is some specuation about "core lock", in
which sounds like the "shock cooling" equivalent for turbines, going
from high power to no power at high, cold altitudes.

Just what is it about "PILOT ERROR" makes the airframe unsafe? If you
are running with scissors, and your mom says "I wouldnt do that if I
were you".. is it the scissors fault?

Dave

[[email protected]]

Mike,

I'm not referring to water in the fuel as we deal with in piston
pounders (and where it would be expected to affect a number of
airplanes), but rather the normal moisture entrained in fuel and that
processes through the system without any effect except at high altitude
where it's so terribly cold and the entrained moisture freezes and can
clog filters with the very small ice particles unless something like
PRIST is used. (Although one poster was correct, it usually takes more
than a few minutes to cool the fuel to the point where the entrained
water freezes. It's more of a concern after about an hour at cruise.)

May not be a good theory as it appears the crew let the speed
deteriorate badly in the final climb to 410 and it continued to bleed
off once there.

All the best,
Rick

[Mike Rapoport]

> wrote in message
ups.com...
> Mike,
>
> I'm not referring to water in the fuel as we deal with in piston
> pounders (and where it would be expected to affect a number of
> airplanes), but rather the normal moisture entrained in fuel and that
> processes through the system without any effect except at high altitude
> where it's so terribly cold and the entrained moisture freezes and can
> clog filters with the very small ice particles unless something like
> PRIST is used. (Although one poster was correct, it usually takes more
> than a few minutes to cool the fuel to the point where the entrained
> water freezes. It's more of a concern after about an hour at cruise.)
>
> May not be a good theory as it appears the crew let the speed
> deteriorate badly in the final climb to 410 and it continued to bleed
> off once there.
>
> All the best,
> Rick


I would still expect that a lot of Jet A buyers are going to FL410 (or
higher) and that if there was enough water in the fuel to crystalize and
block the fuel system to the extent that the engines failed that it would
have affected other planes too. Also, at least in my airplane, you have
some time between when the filter bypass light comes on and when the engines
flame out since the fuel lines are a lot bigger that the filter pores and it
takes more ice to clog them. I always look for what is unique to the
situation and what is common. So, I think that the problem was, most
likely, not the fuel because many others probably bought the fuel and flew
at least as high for at least as long.

I would guess that the pilots had never been anywhere close to FL410 since
it appears unlikely that the plane could reach that altitude with passengers
aboard if it can barely get there empty. They probably didn't remember the
cautions about high altitude flight in the manual. Why they chose to
override the shaker or not set up their glide towards an airport is
baffling.

Mike
MU-2

[B. Jensen]

Rick,

The Lear's you flew were turbojets with small N1 fans. They tend to
work very well at high altitudes. The CRJ is a Fanjet aircraft and has
a big N1 fan that is not the best at high altitudes. From the limited
information I have on this accident, the engines on the CRJ compressor
stalled due to the high angle of attack and low airspeed these guys put
it into trying to get to FL410. The compressor stall caused the engines
to spool down and flame out which then led to the core lock. Once in
core lock, the high pressure compressor section locked up and an
inflight relight was virtually impossible.

This type of engine works great at lower altitudes, but needs TLC at the
higher levels.

BJ


wrote:

>Bob,
>
>This one certainly has me curious as to the cause. I've got very
>limited experience in fanjets, but I've flown them at max operating
>altitude and consider it a normal operation. In the turbojet 20-series
>Lears we regularly went to FL450 in the 23 and 24B (usually after one
>hour of flight) to get the fuel burns as low as possible when hauling
>freight (plus, back then, there was nobody up that high and we always
>got direct). In one version of the 25 we could go to FL510 although
>even when very light, the climb rate going through 490 was so slow we
>wondered whether we'd make 510 before time to start down (and, as you
>know, you could see the curvature of the earth).
>
>I did lose an engine at FL450 in a 24B when the captain moved the power
>levers fairly quickly and an old fuel control unit couldn't handle it
>at that altitude, flaming out the engine. We got a relight at 17,000
>although, as I recall, the relight envelope was supposed to go to
>25,000 (let's just say maintenance at that organization was not exactly
>top notch - long out of business).
>
>As a result, I'm curious as to what would cause both engines to go
>quiet - the only common system is fuel, although I don't know the CRJ
>systems at all and wonder whether there is/are any procedure(s) that
>must be followed above a certain altitude regarding pumps or if the
>company regularly flew so low that they didn't put in any additives
>such as PRIST to prevent ice in the fuel. Have to contact a CRJ
>captain friend of mine and see what she says. Also wondering why the
>relight was unsuccessful...just doesn't make sense, jet engines are so
>darn simple in operation - add fuel, ignite and go. Also wondering why
>they couldn't make an airport from 410 in central Missouri.
>
>The overheating comment on this thread is laughable. And I thought I'd
>heard all of the nutty theories of aircraft accidents. Or maybe it was
>some localized heavy gravity that shortened the glide range....
>
>Your thoughts?
>
>Warmest regards,
>Rick
>
>
>

[Matt Whiting]

Mike Rapoport wrote:

> Keep in mind that it takes a long time to cool fuel in the wing. The top of
> the fuel is not even touching the skin after a small portion is burned off
> and the fuel does not contact the leading edge either. The fuel with the
> highest gel point (Jet A) is still good to below -40C (well below if memory
> serves me correctly. Fuel gelling is a problem in long range aircraft or
> aircraft that have been on the ramp in Thule in Jan. for a couple of days.
> I would be surprised if it applied in this case. There just wasn't enough
> time for the fuel to cool sufficiently.

Yes, I'd think the issue would be fuel in a small fuel line, pump or
filter where things would cool off much more quickly than the bulk fuel
in the tank.

Matt