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All planes
with electric trim are subject to possible runaway trim.
trader4@optonline.net wrote in
news:bc496342-1823-4eb9-9b07-ab96aae6321f@googlegroups.com:
Altitude would not seem to be a parameter in determining if the
plane is stalling or not.
Technically, no, but tons of plane, in the real world, attitude and
airspeed is a huge indicator of "stable flight" or a possible lack
thereof.
trader4@optonline.net wrote in
news:c6b72f5a-7630-453a-a7f9-80adb2e33097@googlegroups.com:
One way would be to look at other data, eg airspeed and attitude
and see if that's consistent with a stall.
How many times a day do you contradict yourself?
You have more than once declared both to be non factors.
And you forgot your always wrong sig.
Lasse Langwadt Christensen <langwadt@fonz.dk> wrote in
news:466ef7dc-0503-4b47-8485-71d8825dd7c5@googlegroups.com:
The biggest issue to me is that there was no release switch to
return
pilot control.
there is, two switches to turn off electric trim and the pilots
are supposed to know how to handle run away trim by memory
I know what is there. You do not understand my statement.
I do not like an actuator arm locked onto my elevator.
removes my control and an emergency cicumstance does not restore
control, it merely gives up as the controlling element.
still then must manually actuate a mecahnism at a much slower rate
than needed, to get back to stick control.
If there is one, it needs to have a FULL release and not be a
manual screw requiring manual return. If it gets released fully,
the pilot's elevator control return is a mere stick push.
trader4@optonline.net wrote in
news:c9077654-80c6-423c-9d4f-43839263f95f@googlegroups.com:
On Monday, May 6, 2019 at 4:12:17 AM UTC-4,
DecadentLinux...@decadence.org wrote:
omnilobe@gmail.com wrote in
news:c53fb380-eaac-4408-9422-959a9d1f8d3f@googlegroups.com:
Boeing is updating its software so the giant engines can
unbalance the airplane the same way as in the two crashes. Do
you want to fly a plane that only software is used to prevent
stalling? Without software it stalls.
The software was for IF the plane stalled, which it did not.
It was
a sensor error.
It is because the pilot does not always have a sense of a stall
situation, which the craft never get into anyway unless the pilot
and copilot are sleeping.
That's incorrect. The pilots know that a stall is approaching
with the STICK SHAKER and audible alerts.
A stalling plane is pilot error, not airplane error.
The issue with the 737 Max is that at high levels of AOA, the
plane has a tendency to nose up even further. Part of the
certification process is that if you release the controls the
plane is supposed to head in a stable direction, not toward
instability. That is why MCAS was added.
The biggest issue to me is that there was no release switch to
return
pilot control.
Wrong again, as proven by the first Lion Air flight that had the
same problem the day before the crash. The pilot in the jump
seat, who was not one of the crew, correctly identified the
runaway trim problem, told the two pilots flying what to do. They
turned off the electric trim, used manual trim and the plane flew
on to it's destination.
Manual recovery from a positioner is NOT "reset and release".
Instead of a slow, manual dial back method, it needs a full release
of the positioner arm on the tail.
The trim is a normal part of the aircraft's control system, and it
doesn't have a fixed correct position to which it could be
restored. It has to be adjusted frequently during the flight
depending on many factors.
An out of trim state is perfectly manageable, provided it's not
allowed to go too far, and the fact that the manual trim is slow
doesn't matter.
On 7/05/2019 12:01 am, trader4@optonline.net wrote:
It would seem most likely that he was trying to turn
the wheel, but could not. If so, that would be another huge problem,
one that could extend to all 737s. Is it possible with extreme trim
and enough airspeed that you can't turn the wheel?
There is some Boeing documentation on this. Mentour Pilot discusses this
in one of his videos - possibly this one.
https://www.youtube.com/watch?v=xixM_cwSLcQ&t=1217s
Certainly the load on the trim jackscrew increases as the aircraft is
further out of trim, and this can reach the level where the pilots are
not strong enough to turn the trim wheels. Boeing suggest briefly
unloading the control column to allow the trim wheels to be turned, and
then loading the control column again to recover the flight path, and do
this repeatedly, until the situation improves.
Of course, to get into that position the pilots have to fail to address
the deteriorating trim situation.
Sylvia.
On 2019-05-06 06:46, trader4@optonline.net wrote:
The issue with the 737 Max is that at high levels of AOA, the plane has
a tendency to nose up even further. Part of the certification process
is that if you release the controls the plane is supposed to head in
a stable direction, not toward instability. That is why MCAS was added.
This is incorrect.
On 05/06/2019 11:55 AM, trader4@optonline.net wrote:
Mushing has nothing to do with what I stated. Explain to us how a 737
that's been going 300 MPH in level flight for 30 seconds can be stalling.
It can't.
Not during those 30 seconds perhaps, but wind shear can change things in
an instant.
The problem here is that you're talking about another piece of
equipment that can control the trim, and which might do so when it
shouldn't. It would then require switches to disable it.
bearing in mind that time is of the
essence.
On 07/05/2019 05:17, Riley Angel wrote:
On 2019-05-06 06:46, trader4@optonline.net wrote:
The issue with the 737 Max is that at high levels of AOA, the plane has
a tendency to nose up even further. Part of the certification process
is that if you release the controls the plane is supposed to head in
a stable direction, not toward instability. That is why MCAS was added.
This is incorrect.
In what way is it incorrect? His description is a fairly succinct
explanation of the problem that MCAS was intended to address. Namely
that the physically bigger engines and shifted centre of gravity made
the plane tend towards an AoA stall condition if left to its own
devices. (but only in some fairly rare edge cases)
The AoA sensor and MCAS was meant to intervene before this happened.
In reality if the AoA sensor went bad MCAS would force the plane nose
down into a steep power dive and generate non-sensical stall warnings.
Worse it was able to reset and do it again and again making far more
significant adjustments to the trim than implied by its specification.
FAA were clearly asleep on the job - their responsibility to do an
independent check that Boeing safety system engineering was sound.
--
Regards,
Martin Brown
Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> wrote in
news:qapdk2$flj$1@dont-email.me:
I have read lately it was, it is anyways in the sense that it did
not detect the output to ever tilt the thing more and more. Looks
like the dumbest loop you can ever write. It did not check angular
position (I think they added that now, only takes a 1$ MEMS chip),
and it had no redundancy.
'and it had no redundancy' which the dopey tradertard4 dipshit will
use to claim he is right.
I said software a long time ago, like the day after it happened.
It was, however there are notable hardware issues which I would
also have done differently.
IOW software change alone could fix it, however there would still
be a chance of the manipulator getting at the end of its travel and
requiring manual reset to the zero trim point.
striong issues where a pilot needs to know how and when a detachment
of this system would be needed to restore pilot control in a
situation where the system was malfucntioning.
They likely needed to install a method to detach the hydraulic arm
completely from the elevator (tail) to 'give back' pilot control if
'requested'.
trader4@optonline.net wrote in news:20104676-2e55-4f19-be8e-
91be4d27d66b@googlegroups.com:
Get it near
neutral, where you know it belongs,
Easy for you to say.
Sylvia Else <sylvia@email.invalid> wrote in
news:gjdaubFo46rU1@mid.individual.net:
The problem here is that you're talking about another piece of
equipment that can control the trim, and which might do so when it
shouldn't. It would then require switches to disable it.
Same equipment, except that instead of a screw jack, it would be a
hydraulic cylinder, and THAT cylinder can be made to be 'freed' either
in the cylinder valving and design itself or by attachment point or
both.
Sylvia Else <sylvia@email.invalid> wrote in
news:gjdaubFo46rU1@mid.individual.net:
An out of trim state is perfectly manageable, provided it's not
allowed to go too far, and the fact that the manual trim is slow
doesn't matter.
It most certainly DOES matter once the autotrim element has moved
the control surface (not just a trim tab) to the complete opposite
extreme.
Time is actually quite critical. And the pilot never needs to be
manually screwing anything back in place. A mere decalaration
should prompt other cabin personnel
given. The plane needs to be designed to operate that way with
MAYBE the pilot's last resort being something local to him and
slower like a dial crank.
Fly by wire schemas are going to be frought with issues over the
next several decades until a proper, trusted redundant control is in
place, and the redundancy level made acceptable.
Planes made that require computer assistance are the most
dangerous from that perspective, because lone pilot control has thus
far been the last resort rule of the day. Bigger planes are not
that easy for a pilot to move control surfaces around on.
On Monday, May 6, 2019 at 5:23:24 PM UTC-4, Lasse Langwadt Christensen wrote:
mandag den 6. maj 2019 kl. 22.59.28 UTC+2 skrev tra...@optonline.net:
On Monday, May 6, 2019 at 4:12:21 PM UTC-4, Lasse Langwadt Christensen wrote:
if the force needed to trim up is so high you can hardly move the trim wheel won't the electric trim be useless as well?
Very good question, but obviously the electric does still work, because
on these flights they were able to keep bringing trim back up and MCAS
was able to push it down. How you reconcile those, IDK. Also, if it
really was impossible for that Ethiopian co-pilot to turn the trim
wheel, seems there is more wrong there than just MCAS. It would imply
that on any 737, if you have a runaway trim and it goes to hard trim
in either direction, you may not be able to counter it by the stated
trim procedure.
I saw this snipped from the 737 Flight Crew Training Manual, chapter Non-Normal Operations/Flight Controls, sub heading Manual Stabilizer trim:
"Excessive air loads on the stabilizer may require effort by both pilots to correct mis-trim. In extreme cases it may be necessary to aerodynamically relieve the air loads to allow manual trimming. Accelerate or decelerate towards the in-trim speed while attempting to trim manually."
Well, that answers one question. Apparently it's known and accepted that
with enough trim and speed, you can't wind it by hand. Which makes the
MCAS design all the more worse. A weathervane blowing in the wind can
force the nose down hard, continually and if it's hard enough and
you just follow the runaway trim procedure, you might not be able
to recover period. Even worse, if the AOA is screwed, like the LA one
was, reading 20 deg on the ground, when does MCAS try to kill you?
Just as you're retracting the flaps, which means right after takeoff,
at low altitude, where there may not be enough time to figure it out
and recover.
On Tuesday, May 7, 2019 at 8:20:34 AM UTC-4, Sylvia Else wrote:
On 7/05/2019 9:38 pm, DecadentLinuxUserNumeroUno@decadence.org wrote:
Lasse Langwadt Christensen <langwadt@fonz.dk> wrote in
news:466ef7dc-0503-4b47-8485-71d8825dd7c5@googlegroups.com:
The biggest issue to me is that there was no release switch to
return
pilot control.
there is, two switches to turn off electric trim and the pilots
are supposed to know how to handle run away trim by memory
I know what is there. You do not understand my statement.
I do not like an actuator arm locked onto my elevator. That
removes my control and an emergency cicumstance does not restore
control, it merely gives up as the controlling element. The pilot
still then must manually actuate a mecahnism at a much slower rate
than needed, to get back to stick control.
If there is one, it needs to have a FULL release and not be a
manual screw requiring manual return. If it gets released fully,
the pilot's elevator control return is a mere stick push.
The trim is a normal part of the aircraft's control system, and it
doesn't have a fixed correct position to which it could be restored. It
has to be adjusted frequently during the flight depending on many
factors. In the 737, the trim is adjusted by having the tailplane driven
by a jackscrew. The only way that the trim can be restored to its
currently correct state after something has driven wrongly it is to turn
the jackscrew the other way. Once you've disabled the power to the
jackscrew motor, human power is the only way it can be done.
I may be wrong, but I believe there is still hydraulic assist or similar
to the jackscrew for a number of reasons, one of which is that you could
not exert enough force to turn it by hand. I think the electric cutoff
to the trim disables a small motor that moves the trim wheels, which in
turn drive the motor that moves the jackscrew.
On Tuesday, May 7, 2019 at 7:26:15 AM UTC-4,
DecadentLinux...@decadence.org wrote:
trader4@optonline.net wrote in
news:c6b72f5a-7630-453a-a7f9-80adb2e33097@googlegroups.com:
One way would be to look at other data, eg airspeed and
attitude and see if that's consistent with a stall.
How many times a day do you contradict yourself?
You have more than once declared both to be non factors.
And you forgot your always wrong sig.
Wrong always wrong. I always said attitude and airspeed. You
just can't read, thought I said "altitude" in a post you replied
to. I corrected you there too.
Wrong, always wrong.