Posted on 02/23/2019 1:05:56 PM PST by Ronald_Magnus
That’s a better video. They were angled down at 55 degrees from the horizon, I believe.
Clearly not weather-related, and not an inadvertent stall recovery attempt — at high speed it takes just a little yoke travel to make a large difference in trajectory.
There’s no history of 767’s and partial or full elevator failure — like there was with 737’s and rudders for a time.
I won’t rule out the unthinkable.
And that accident led to preventative measures on all 767's:
As a result of their findings during the investigation process of Lauda Flight 004, additional safety features such as mechanical positive locks were mandated to prevent thrust reverser deployment in flight.
https://en.wikipedia.org/wiki/Lauda_Air_Flight_004
Houston news showed camera shot of the plane going down in good weather. It was heading nearly nose down.
55 degrees nose low, I think.
...Also, about this time, the FDR data indicated that some small vertical accelerations consistent with the airplane entering turbulence. Shortly after, when the airplane’s indicated airspeed was steady about 230 knots, the engines increased to maximum thrust, and the airplane pitch increased to about 4° nose up and then rapidly pitched nose down to about 49° in response to column input. The stall warning (stick shaker) did not activate. FDR, radar, and ADS-B data indicated that the airplane entered a rapid descent on a heading of 270°, reaching an airspeed of about 430 knots. A security camera video (figure 4) captured the airplane in a steep, generally wings-level attitude until impact with the swamp. FDR data indicated that the airplane gradually pitched up to about 20 degrees nose down during the descent.
https://www.ntsb.gov/investigations/Pages/DCA19MA086.aspx
...Also, about this time, the FDR data indicated that some small vertical accelerations consistent with the airplane entering turbulence. Shortly after, when the airplane’s indicated airspeed was steady about 230 knots, the engines increased to maximum thrust, and the airplane pitch increased to about 4° nose up and then rapidly pitched nose down to about 49° in response to column input. The stall warning (stick shaker) did not activate. FDR, radar, and ADS-B data indicated that the airplane entered a rapid descent on a heading of 270°, reaching an airspeed of about 430 knots. A security camera video (figure 4) captured the airplane in a steep, generally wings-level attitude until impact with the swamp. FDR data indicated that the airplane gradually pitched up to about 20 degrees nose down during the descent.
https://www.ntsb.gov/investigations/Pages/DCA19MA086.aspx
Thanks. I posted a thread on it:
It looks like either one of the pilots or the autopilot flew it into the ground.
http://www.freerepublic.com/focus/f-news/3734036/posts
The fact that the dive was arrested to 20 degrees nose-low seems to suggest either a struggle by one pilot against the strength of the other, or a struggle against the (still-connected) autopilot to pull out of the dive.
In the Egypt Air flight 990 crash (also a 767) the pilots were fighting each other’s control input to the point that the horizontal stabilizer linkage separated, with each side contolling only half of the horizontal stab. That would diminish either pilot’s ability to pull out of a dive (or to steepen the dive) if they were in opposition in their yoke movements. There hasn’t been enough data released from this mishap to know.
Right now I am leaning even more toward the “deliberate act” scenario. Occam’s razor.
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