Is the 787 a failure ?

Jim Wilkins wrote:
"Mr. B1ack" wrote in message
...

Not interested in burning to death over the Pacific ....

Better to fall into the South Atlantic because the Airbust didn't
inform the pilots that it had stalled.

Actually it did, they simply chose to disregard the stall warning
that sounded continuously for 54 seconds and the stick shaker.

Keith

"Keith W" wrote in message
...
Jim Wilkins wrote:
"Mr. B1ack" wrote in message
...

Not interested in burning to death over the Pacific ....

Better to fall into the South Atlantic because the Airbust didn't
inform the pilots that it had stalled.

Actually it did, they simply chose to disregard the stall warning
that sounded continuously for 54 seconds and the stick shaker.

Keith

It sounded for 54 seconds, then it stopped a little after 2h 11m 42s
when they were at 35,000 feet, 40 degrees pitch and falling at 10,000
feet/minute. See pages 22 & 23.
http://www.bea.aero/en/enquetes/flig...t.final.en.php

At 2h 12m ~15s the Pilot Flying made a pitch-down input that brought
their forward speed above the stall warning's lower limit of 60 Kts
and it sounded again, confusing them.

Page 44 of the final report:
" If the CAS measurements for
the three ADR are lower than 60 kt, the angle of attack values of the
three ADR are
invalid and the stall warning is then inoperative."

My real point is to remind Bill Black that he lives in a glass house
and shouldn't throw stones at Boeing.
jsw

Jim Wilkins wrote:
"Keith W" wrote in message
...
Jim Wilkins wrote:
"Mr. B1ack" wrote in message
...

Not interested in burning to death over the Pacific ....

Better to fall into the South Atlantic because the Airbust didn't
inform the pilots that it had stalled.

Actually it did, they simply chose to disregard the stall warning
that sounded continuously for 54 seconds and the stick shaker.

Keith

It sounded for 54 seconds, then it stopped a little after 2h 11m 42s
when they were at 35,000 feet, 40 degrees pitch and falling at 10,000
feet/minute. See pages 22 & 23.
http://www.bea.aero/en/enquetes/flig...t.final.en.php

At 2h 12m ~15s the Pilot Flying made a pitch-down input that brought
their forward speed above the stall warning's lower limit of 60 Kts
and it sounded again, confusing them.

Page 44 of the final report:
" If the CAS measurements for
the three ADR are lower than 60 kt, the angle of attack values of the
three ADR are
invalid and the stall warning is then inoperative."

My real point is to remind Bill Black that he lives in a glass house
and shouldn't throw stones at Boeing.
jsw

The real point is that the aircraft clearly

1) Indicated that it had reverted to direct law (manual input)
2) Sounded the stall warning
3) Showed that the aircraft was falling at a high angle of attack
and low speed

The pilot flying seems to have been fixated on keeping the
wings level and disregarded the angle of attack which at
2 minutes 12 seconds was 40 degrees ! During the entire
crisis it was never less than 35 degrees.

Keith

"Keith W" wrote in message
news
Jim Wilkins wrote:

At 2h 12m ~15s the Pilot Flying made a pitch-down input that
brought
their forward speed above the stall warning's lower limit of 60 Kts
and it sounded again, confusing them.

Page 44 of the final report:
" If the CAS measurements for
the three ADR are lower than 60 kt, the angle of attack values of
the
three ADR are
invalid and the stall warning is then inoperative."

My real point is to remind Bill Black that he lives in a glass
house
and shouldn't throw stones at Boeing.
jsw

The real point is that the aircraft clearly

1) Indicated that it had reverted to direct law (manual input)
2) Sounded the stall warning
3) Showed that the aircraft was falling at a high angle of attack
and low speed

The pilot flying seems to have been fixated on keeping the
wings level and disregarded the angle of attack which at
2 minutes 12 seconds was 40 degrees ! During the entire
crisis it was never less than 35 degrees.

Keith

"When the calculation of the Vsw speed is not available, this speed is
no longer
displayed on the PFDs. No visual information is then displayed that is
specific to the
approach to stall."

"The angle of attack is the parameter that allows the stall warning to
be triggered. Its
value is not directly displayed to the pilots."

They knew their small nose-up angle, but not the large relative wind
direction component of AoA.

Speculation based on similar non-fatal incidents:
"The reappearance of the flight directors on the PFD when two
airspeeds are calculated
as similar may prompt the crew to promptly engage an autopilot.
However, although
the magnitude of these speeds may be the same, they may be erroneous
and low,
and could cause the autopilot to command flight control surface
movements that are
incompatible with the aircraft's actual speed.

They dance around the possibility that the Flight Director crossbars
on the Primary Flight Display might have misled the crew. The PFD is
on page 39. The reconstructon of information available to the crew
begins on p.93.
jsw

"Jim Wilkins" wrote in message
...
"The angle of attack is the parameter that allows the stall warning
to be triggered. Its
value is not directly displayed to the pilots."

They knew their small nose-up angle, but not the large relative wind
direction component of AoA.

jsw

If that's unclear, they were pitched up 5 degrees and descending at 35
degrees for a combined AoA of 40 degrees.
jsw

On Fri, 22 Mar 2013 16:39:07 -0000, "Keith W"
wrote:

Jim Wilkins wrote:
"Mr. B1ack" wrote in message
...

Not interested in burning to death over the Pacific ....

Better to fall into the South Atlantic because the Airbust didn't
inform the pilots that it had stalled.

Actually it did, they simply chose to disregard the stall warning
that sounded continuously for 54 seconds and the stick shaker.

Keith


Because they believed the air speed indicator that was lying through
it's teeth.

wrote in message
...

Because they believed the air speed indicator that was lying through
it's teeth.


Or maybe they continued to doubt it after the ice cleared?

The report didn't try too hard to reconstruct what they might have
believed, beyond recounting similar incidents. The pilots do appear to
have interpreted what they saw differently and acted without
coordination. The Flight Data Recorder didn't capture all their
displays. The report mentions that pilots fly their mental perception
of the situation.

AFAICT they assumed they still had adequate speed and lift and didn't
understand why the instruments showed them rapidly descending although
they had applied full power and pulled the nose slightly up.
Apparently that aircraft just mushes down flat when it stalls. They
had trouble controlling roll but not pitch.

My guess is that they assumed from the abnormally high air temperature
in the top of the storm that there might be strong vertical air
currents and may have believed they were caught in a turbulent
downdraft. The voice recording reveals mainly confusion.
jsw