When 'psycho' automation left this pilot powerless

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HJ1an
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Re: When 'psycho' automation left this pilot powerless

Postby HJ1an » Sun Nov 05, 2017 3:56 am

Stalling is bad. I can't see under any circumstances can the stalling the wings could be good. (Except for 2 things : you are trying to find its limits in a test flight to match the projected design numbers, or you're trying to COBRA maneuver in order to avoid incoming missiles... which the Triple Seven can't do obviously). Therefore the compter preventing a hard stall is always good thing. I'm not sure if Boeing allows the plane to stall before settling it back to the flight path quickly, or how its protection is coded. So in terms of AoA I'm not familiar.

But a roll, on the other hand, I know this could be overriden on a 787 simply by pushing it past the limit, and I can think of a handful of situations that may be needed. I don't know if the 777 also does this, but given Boeing's philosophy I would assume so. AFAIK, Airbus doesn't allow this, with angles fixed at 66 degrees. In a Boeing you could probably roll upside down, with the warnings blaring at you while you James Bond your way around enemy Sukhois or whatever, but in Airbus it will always be fixed at 66 degrees (or less considering weight, fuel etc) no matter what.

They both have their advantages - e.g. if somehow a nutcase got into the cockpit then it's the Boeing that will suffer from this philosophy, but if somehow a navigation error led to a brush with the mountain side cliff, the Airbus may not be able to maneuver out of that successfully. Thoug in both cases are a bit far fetched to be honest.

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it0uchpods
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Re: When 'psycho' automation left this pilot powerless

Postby it0uchpods » Sun Nov 05, 2017 1:55 pm

Please just watch the video so you can be informed.

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jwocky
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Re: When 'psycho' automation left this pilot powerless

Postby jwocky » Sun Nov 05, 2017 2:09 pm

Sorry that I made a joke about the holy cows of the Boeing and Airbus factions. Usually, aircraft are more technical than sacrosanct things.
And on a rather general point of view, there have been throughout history always phases of an uncritical belief in technology. Usually, those beliefs got broken when enough people had died from it. However, we live in cynical times. In 1912, roughly 1500 people died and that was impact enough to change a whole industry. Nowadays, 1500 lives are just the costs of doing business or sometimes the ball in ideological ball games. That is what makes me sometimes a bit worrying.
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HJ1an
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Re: When 'psycho' automation left this pilot powerless

Postby HJ1an » Mon Nov 06, 2017 12:56 am

jwocky wrote: In 1912, roughly 1500 people died and that was impact enough to change a whole industry. Nowadays, 1500 lives are just the costs of doing business or sometimes the ball in ideological ball games. That is what makes me sometimes a bit worrying.


Hmmm, interesting quote. And that sounds about right too.

See: (from what I could think up) Melamine milk powder scandal, Takata, Kobe steel, VW diesel scandal, etc. All the result of business decisions over lives.

it0uchpods wrote:Please just watch the video so you can be informed.


Sorry, I'd prefer to get this info from the technical manuals from Boeing / Airbus rather than from a youtube video of a computer simulator.

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Re: When 'psycho' automation left this pilot powerless

Postby it0uchpods » Mon Nov 06, 2017 1:50 am

Well, if you don't trust that, then go look up the FCOM.

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KL-666
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Re: When 'psycho' automation left this pilot powerless

Postby KL-666 » Mon Nov 06, 2017 2:13 am

I'd just recommend to the IDG people to try to really understand the logic of trim-for-speed. For Airbus adepts it is really hard to understand, as they are used to AoA protections. And this is not a protection, but a reprisal to the airlines demanding more automation, due to being infected by Airbus propaganda.

But Boeing did not want to add an unrealistic experience for pilots. So they came up with trim-for-speed. It is very close to real flight, so they could live with implementing it. But again, very hard to understand for Airbus adepts, because it is not a protection. To the Airbus adepts: if you really want to understand this principle and the enormous difference with Airbus logic, do a lot of reading of quality material. Do not let yourself be fooled by a repetition of Airbus propaganda by some gamer.

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Re: When 'psycho' automation left this pilot powerless

Postby it0uchpods » Mon Nov 06, 2017 3:38 am

Sorry -- but I already done so!!!! ???? !!!! :D

I'm sorry if you don't understand what I'm talking about.

THE 777 will limit the pitch trim and elevator deflection when nearing a stall... IT IS A PROTECTION!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! I promise that.

It happens in the Normal Law.

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HJ1an
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Re: When 'psycho' automation left this pilot powerless

Postby HJ1an » Mon Nov 06, 2017 3:43 am

it0uchpods wrote:IT IS A PROTECTION!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! I promise that.


It _is_ a protection. But again, this isn't the point of the discussion is it? It's the philosophy behind it and how they handle the protection that is being discussed.

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it0uchpods
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Re: When 'psycho' automation left this pilot powerless

Postby it0uchpods » Mon Nov 06, 2017 4:00 am

It cannot be overridden by the pilot -- basically the same as the Airbus stall protection -- cannot be overridden by pilot -- based on AoA.

Unless the 777 pilot switches off his PFC computers on overhead... so you are talking about a switch?

AFAIK, turning off the Airbus PRIM/SEC (or for A320, ELAC/SEC/FAC) switches on overhead will revert the laws.

So basically, it's the same.

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HJ1an
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Re: When 'psycho' automation left this pilot powerless

Postby HJ1an » Mon Nov 06, 2017 6:17 am

it0uchpods wrote:It cannot be overridden by the pilot -- basically the same as the Airbus stall protection -- cannot be overridden by pilot -- based on AoA.



As I said, I don't know AoA. And also, as I also said, I don't see a scenario where stalling the aircraft is a good idea. The protection built in here, whether flight envelope protection or trim-for-speed, has a good reason to be in effect.

But let's talk about hard protections:

Case study : Federal Express Flight 705 https://en.wikipedia.org/wiki/Federal_E ... Flight_705

In order to keep his attacker at bay, the pilot of this flight had no choice but to roll his plane nearly inverted at 140 degrees, and subsequently dives, overspeeding, and other extreme motions that a normal commercial jetliner would never even see in its flying service. The pilot's jetfighter maneuvers were really the only thing that saved the lives of others in the cabin in order to throw the attacker off balance. And the last minute decision change of runway saw the jet bank at angles it is never built for, but with time constraint, the pilot landed safely.

If this were an Airbus, those maneuvers would be impossible, throwing the attacker off balance would be quite a bit harder, if at all, and the runway change would've taken quite a bit longer to do so. As a life and death situation, timing is critical, and it may not be possible.

Given the situation it is most definintely more preferable to have a 'protection' that allows for more extreme maneuvers when needed, than one that has hard limits built in that aren't easily switched off.


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