Earlier quoted context omitted.
If anyone wonders this is how it looks like: https://youtu.be/-X01uY0bJs0?t=48
And sounds ? The trim wheels moving also makes a sound?
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Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix
51–60 of 272 posts
Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix
#52Earlier quoted context omitted.
> In Boeing airplanes, the movement of the two yokes is synchronized. So in case of two equally strong and equally determined pilots you still get averaging of opposing control inputs.
If they're mechanically linked, the captain would at least feel the first officer countering their inputs -- giving a prompt that they need to communicate their intentions more clearly! I'll defer to a pilot to say whether they are mechanically linked -- it sounds like they are on Boeing aircraft but possibly not on Airbus?
They're mechanically linked on Boeing aircraft. On the 757, and I believe the rest, the mechanical link has a detent. With enough force, the pilot can move it out of the detent and move the controls independently of the copilot. The reason for this is if one side or the other is jammed, the pilot can still fly it.
Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix
#53Earlier quoted context omitted.
If anyone wonders this is how it looks like: https://youtu.be/-X01uY0bJs0?t=48
And sounds ? The trim wheels moving also makes a sound?
You'll note in that video, the left-hand pilot has a headset on, presumably the right-hand pilot does too. Headsets are seen in other videos [1] of the cockpit.
So even if the spinning trim wheels make noise, they may not have heard it.
(My google image search shows some pilots wearing two-ear headsets, some wearing one-ear headsets, some wearing two-ear headsets with side not on their ear, and some not wearing headsets. But some of those are pilots posing for photos, and presumably pilots don't let people visit the cockpit during critical stages of the flight)
Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix
#54Earlier quoted context omitted.
> In Boeing airplanes, the movement of the two yokes is synchronized. So in case of two equally strong and equally determined pilots you still get averaging of opposing control inputs.
No, the failure mode is not two pilots consciously fighting against each other. The failure mode is two pilots who are UNAWARE they are commanding contradicting inputs. Airbus negligently averages these inputs. This is legacy tech debt because the physical design didn’t leave room to link the two controls. Now they are stuck because they feel they can’t change and have some planes that (dangerously) average the input…
> Think of this every time you fly Airbus.
Why? They're not falling out of the sky so the system obviously works. Stop being a fanboy.
Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix
#55Best book I've ever read on the root cause ("tight coupling") of accidents: https://en.wikipedia.org/wiki/Normal_Accidents
From its Wikipedia entry:
>"Normal Accidents: Living with High-Risk Technologies" is a 1984 book by Yale sociologist Charles Perrow, which provides a detailed analysis of complex systems from a sociological perspective. It was the first to "propose a framework for characterizing complex technological systems such as air traffic, marine traffic, chemical plants, dams, and especially nuclear power plants according to their riskiness." Perrow argues that multiple and unexpected failures are built into society's complex and tightly coupled systems. Such accidents are unavoidable and cannot be designed around.
His analysis also applies to anesthesia disasters, I learned the hard way during my 38 years in the O.R. Highly recommended.
Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix
#56Earlier quoted context omitted.
That's the most amazing revelation to me so far. The same plane had an identical uncontrolled-dive problem the day before, which required an emergency power cut to the improperly-engaged motor, and somehow that incident didn't ground the plane or even result in any effective advisory to the next crew. Further, the Bloomberg story reports: "The Indonesia safety committee report said the plane had had multiple failures…
> Lots of blame to go around here. Only if the faulty sensor was listed as "critical." Boeing didn't declare it as such and reported to nobody the way it was used in the unreported MCAS. That the MCAS even exists and that a single faulty sensor was enough to mess with the flight erratically enough to confuse the pilots was somehow acknowledged by Boeing only after the first crash. It took the second crash for most ob…
Even if they didn't know about the MCAS, they still knew the plane had had an uncontrolled-dive problem from an unknown cause. How is it responsible to fly it without understanding the issue?
Boeing is still fully culpable, but the airline should have debugged the issue before using the plane again.
Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix
#57This appears to answer the question of why, given that there is a "memory item" for dealing with runaway trim that would have helped, it wasn't followed by the crew: > “They didn’t seem to know the trim was moving down,” the third source said. “They thought only about airspeed and altitude. That was the only thing they talked about.” If this is true, not only did the pilots not realize the trim was the cause of the d…
This is not true, on the released FDR data, it shows clearly that the pilot flying corrected the MCAS system's trim down adjustments at every cycle (each 10 seconds) for most of the level flight. So at least the PF must have been aware of this. It's a bit weird if they didn't talk about it though, maybe it was obvious to both pilots and they were concentrating on if they were keeping altitude and airspeed at all (the most important factors that would keep them flying).
Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix
#58I'm trying to imagine the horror the pilots (and passengers) were feeling. Imagine your car slowly starting to shift sideways into incoming traffic, and no matter how hard you pull the steering wheel, you can't get it back. Horrifying.
This is why I refuse to listen to these things when they're released. The thought of eavesdropping in on someone's frantic hopeless fight for survival just doesn't sit right with me.
Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix
#59Earlier quoted context omitted.
> In Boeing airplanes, the movement of the two yokes is synchronized. So in case of two equally strong and equally determined pilots you still get averaging of opposing control inputs.
No, the failure mode is not two pilots consciously fighting against each other. The failure mode is two pilots who are UNAWARE they are commanding contradicting inputs. Airbus negligently averages these inputs. This is legacy tech debt because the physical design didn’t leave room to link the two controls. Now they are stuck because they feel they can’t change and have some planes that (dangerously) average the input…
>Now they are stuck because they feel they can’t change and have some planes that (dangerously) average the inputs, and some that are physically linked.
This is a really weird way to construe the situation. The accident report doesn't conclude that the handling of dual inputs was a factor, and it's clear from the transcripts that it wasn't. Airbus has no reason to change this.
Merely linking sidesticks would be pointless in any case, since sidesticks don't have an identifiable position (but are used with brief movements away from center). It's hardly any easier for a pilot to passively observe the movements of his own sidestick than it is just to look over at the other pilot's stick.
Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix
#60In the other news, on the previous day on the same plane there was a retired pilot flying in cockpit who correctly diagnosed problem & told how to disable malfunctioning system: https://www.bloomberg.com/news/articles/2019-03-19/how-an-ex...
That's the most amazing revelation to me so far. The same plane had an identical uncontrolled-dive problem the day before, which required an emergency power cut to the improperly-engaged motor, and somehow that incident didn't ground the plane or even result in any effective advisory to the next crew. Further, the Bloomberg story reports: "The Indonesia safety committee report said the plane had had multiple failures…
The same plane had an identical uncontrolled-dive problem
the day before, [...] and somehow that incident didn't
ground the plane or even result in any effective advisory
to the next crew.
If the pilots fear near misses will be called pilot error, and they'll be called incompetent/dangerous or punished for endangering passengers, that would do a lot to discourage near miss reporting.