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A330 flight control laws saved Voyager, inquiry finds

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Re: A330 flight control laws saved Voyager, inquiry finds

#151

Post by Angostura »

closeparen wrote: post #83
kristianp wrote: post #20

Earlier quoted context omitted.

It's a safety concern that at least 50 passengers didn't have their seat-belts on!

Is it me or has seat-belt-sign discipline gone out the window? Over my December travels, dozens of passengers on all 4 segments I flew openly flaunted the seat-belt sign, getting up to go to the bathroom and standing in the aisle waiting for it in full view of flight attendants, who didn't say anything. I broke down and did so myself, as the seat belt sign was on for the vast majority of the flight and I was getting…

Just to point out - I think you meant 'flouted' not flaunted

Re: A330 flight control laws saved Voyager, inquiry finds

#152

Post by ptaffs »

JshWright wrote: post #64
sanatgersappa wrote: post #60

Earlier quoted context omitted.

souls. Not bodies.

Not sure if you're serious or not, but 'souls' is the term used to refer to everyone onboard a plane (when declaring an emergency, etc)

I flew with my final-trimester (ie very visibly) pregnant wife in a small helicopter. The pilot announced the number of souls including the unborn, i was, (and still aren't) sure whether this was just cute for effect, or what he was supposed to do.

Re: A330 flight control laws saved Voyager, inquiry finds

#153

Post by Gravityloss »

tropo wrote: post #43
jsmthrowaway wrote: post #35

Earlier quoted context omitted.

The computer worked to prevent the aircraft from entering an overspeed condition by pitching up and attempting to recover from the dive even before that dual stick input was an issue. It was intervening 13 seconds into the incident, as the aircraft threatened to exceed safety tolerances. The dual stick input created another issue after that intervention began. The automation very possibly saved lives here. The oversp…

Nope, it wouldn't happen in a Boeing aircraft. This is a well-known Airbus defect that was a contributing factor to the crash of Air France Flight 447. Boeing uses traditional controls. It's like a race car steering wheel on a big movable stick. It is really easy to see how the control is positioned. Airbus uses a small joystick off to the side. It is force-based like a Thinkpad pointing stick, so it barely moves whe…

Pilot makes a gross error, Airbus software saves the day ... cue comment how this shows Boeing is better.

Re: A330 flight control laws saved Voyager, inquiry finds

#154

Post by JshWright »

FabHK wrote: post #142
JshWright wrote: post #68

Earlier quoted context omitted.

The biggest advantage of the Boeing approach is that the controls are linked; if one moves, so does the other. Mismatched inputs are impossible. I truly don't understand the Airbus approach... There is no method of resolving conflicts between the sticks that make sense... Sum them? Average them? Take the last seen input? Prefer the left side always?

Of course there is a system, and it's sophisticated. Averages are taken in case of inputs on both, and there's a priority button to take precedence (so that the other is ignored). There's more to it than that, but of course there's a system and a lot of thought has gone into it. In the AF 447 case, the left pilot did take priority, but the dude on the right took it back. Had the left one taken it and held it (by keep…

I'm not saying it wasn't thought out, I'm saying that no amount of thought could result in a system that made sense in every situation... Having two independent control inputs means there is always room for subtle failure modes (either technical or operator related).

Multi-master is a tricky problem to solve. When it comes to flying a plane, sitting here in my armchair, I think the the simpler solution (linked yokes) is likely the better one.

Re: A330 flight control laws saved Voyager, inquiry finds

#155

Post by JshWright »

gumby wrote: post #91
JshWright wrote: post #64

Earlier quoted context omitted.

Not sure if you're serious or not, but 'souls' is the term used to refer to everyone onboard a plane (when declaring an emergency, etc)

It was a military plane. It would not be astonishing if it turned out that the number of bodies aboard were significantly greater than the number of souls aboard. (Actually the way I see it there are never more than zero souls aboard, but I understand it's a metaphor)

It's not a metaphor, it's just jargon. It's how the total number of people on board an aircraft is clearly expressed without the confusion of "I've got 37 people aboard" "Ok... is that 37 including you, or 37 plus the pilot?"

Re: A330 flight control laws saved Voyager, inquiry finds

#157

Post by CWuestefeld »

closeparen wrote: post #83
kristianp wrote: post #20

Earlier quoted context omitted.

It's a safety concern that at least 50 passengers didn't have their seat-belts on!

Is it me or has seat-belt-sign discipline gone out the window? Over my December travels, dozens of passengers on all 4 segments I flew openly flaunted the seat-belt sign, getting up to go to the bathroom and standing in the aisle waiting for it in full view of flight attendants, who didn't say anything. I broke down and did so myself, as the seat belt sign was on for the vast majority of the flight and I was getting…

My experience in the past year is attendants being much more strict on the "no standing in line for the bathroom" thing.

Honestly, I don't understand how this is supposed to work. If we can't get in line, then we have to watch carefully, and as soon as someone leaves the bathroom, jump up and run down the aisle to it. But everyone else who wants to go is doing the same, which means that the person whose seat is closest to the bathroom wins, and everyone else needs to got back to their seats. So people farther away don't get to go, while those sitting near them also grow increasingly frustrated.

Re: A330 flight control laws saved Voyager, inquiry finds

#158

Post by marcosdumay »

msandford wrote: post #127
dorfsmay wrote: post #108

Earlier quoted context omitted.

In the case of AF447, the first officer (Robert) has to constantly ask the second officer (Bonin) what he is doing and why he is climbing, he's clearly worried about air speed (starting at 2:10:16 in [1]. Had the FO had direct control over the input, he could have felt that the SO was pulling back, and push back the column in neutral himself. In the case of Crossair 498 (your first link), the copilot knew the captain…

> In the case of AF447, the first officer (Robert) has to constantly ask the second officer (Bonin) what he is doing and why he is climbing The fact that this happens at all makes me think that there could have been a hardware malfunction or that something got wedged forcing the stick back ever so slightly. So FO says "why are you pulling back?" and SO doesn't even respond since his hand isn't on the control. In this…

I didn't look at the details, but keep in mind that AF447 lost the airspeed measurement. I'd guess the pilot is probably looking at the instruments, with wrong speed values, instead of the lever that never moves anyway.

Re: A330 flight control laws saved Voyager, inquiry finds

#159

Post by marcosdumay »

Neliquat wrote: post #65
mbrookes wrote: post #32

"Modern technology may be capable of reducing crew workload to historic lows" It's stated as benefit, but is this the reason pilots get bored perhaps?

Exactly. This is why level 2-4 automated cars scare the hell out of me.

Level 3 is already ok. It means the car deals with anything that happens. It's level 2 that is the problem, and guess where most cars are now?

Re: A330 flight control laws saved Voyager, inquiry finds

#160

Post by awinter-py »

Xixi wrote: post #137
jsmthrowaway wrote: post #35

Earlier quoted context omitted.

The computer worked to prevent the aircraft from entering an overspeed condition by pitching up and attempting to recover from the dive even before that dual stick input was an issue. It was intervening 13 seconds into the incident, as the aircraft threatened to exceed safety tolerances. The dual stick input created another issue after that intervention began. The automation very possibly saved lives here. The oversp…

All modern Boeings (>= B777) are FBW (fly by wire) and have flight envelope protection. A 787 will absolutely not go over-speed: it will automatically throttle back.

Will throttling back help? The plane is pitched down 18 degrees and mach 0.9 KIAS.
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