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-   -   AF 447 Thread No. 9 (https://www.pprune.org/tech-log/489774-af-447-thread-no-9-a.html)

jcjeant 11th Aug 2012 01:38


Not so simple if the pilot isn't used to it, as studi points out.
If a pilot can't use (or had forget how to use) ALL moving surfaces of a plane ... this is not the good job for him ... IMHO

Manual control does not necessarily mean manual trim
Full authority .. yes ..
My aircraft

DozyWannabe 11th Aug 2012 01:45


Originally Posted by jcjeant (Post 7353293)
If a pilot can't use (or had forget how to use) ALL moving surfaces of a plane ... this is not the good job for him ... IMHO
Full authority .. yes ..

The pilot can command autotrim from the sidestick. Easy as pie.

Lyman 11th Aug 2012 01:52

Do oh oh Z...

"The pilot can command autotrim from the sidestick. Easy as pie..


If he can command it, it is not AUTO..... He is flying a powered elevator, and if he snuffs Autotrim, he'll get fired....

Auto/Manual, there is a difference....

DozyWannabe 11th Aug 2012 02:02


Originally Posted by Lyman (Post 7353300)
If he can command it, it is not AUTO..... He is flying a powered elevator, and if he snuffs Autotrim, he'll get fired....

Auto/Manual, there is a difference....

Firstly - proof of what you're saying please.

Secondly - autotrim is separate and distinct from flightpath automation and always has been.

Finally - autotrim is separate and distinct from FMS/FMC automation and is slaved to pitch commands made by the PIC. Autotrim is an automatic system slaved to the pitch commands given to the aircraft whether those commands come from the FMC/FD/Autopilot or the guy sitting in the command seat. Autotrim cannot be "snuffed" or disabled through crew action.

OK465 11th Aug 2012 02:09

This is like 'good cop', 'bad cop'.

DozyWannabe 11th Aug 2012 02:13

Try "thoroughly fed-up cop".

;)

Lyman 11th Aug 2012 02:16

Toody and Muldoon? Friday and Smith? Cramden and Norton? Butch and Sundance?

Dopey and Sneezy?

yeah...wait, the Ministry of Silly Walks?

DozyWannabe 11th Aug 2012 02:25

I was thinking Bayliss and Pembleton.

Lyman 11th Aug 2012 02:28

Baywatch and Pendleton?

No se, amigo....

DozyWannabe 11th Aug 2012 02:40

Bayliss and Pembleton (or Pellegrini and Edgerton):


If you don't understand, likely you never will.

TTex600 11th Aug 2012 03:05


Originally Posted by DozyWannabe

Even if autotrim was limited or disabled in Alternate, the end result of AF447 would have been the same .......

Why do you assume so much?

How can you say the end result would be the same?

Until you know why he continued to pull, you just can't make that assumption.

It is very possible that the pilots would have recognized the stalled condition had the stab remained at cruise setting. In that case, every time he released back pressure, the nose would have dropped, and it might have sunk into his conscience that his pull was in fact the problem. But I'll admit that the preceding is just my opinion. You might try the same tactic.

CONF iture 11th Aug 2012 04:47


No CONF, I have a conception of the logic at engineering level. If you want to think of it as a physical analogy, picture a metal sheet in a G-clamp. The Normal Law protections are the G-clamp and prevent the flight surfaces from exceeding a certain position. The closer to the airframe limits the aircraft gets, the tighter the G-clamp is wound, but the protections do not directly order the flight surfaces not to exceed a given position.

Take the G-clamp away and there is no restriction.
You are fascinating in your style Dozy, you are told how you're wrong but still manage to explain me how it works in the very next post. Your place is in Politics, whatever the winds stay on your feet and talk, just talk.

G-CLAMP ... I like a dozen of them or is it just an ident ?

Excuse my sarcasm really, but that guy has no limit.

jcjeant 11th Aug 2012 06:51


The pilot can command autotrim from the sidestick
That's exact .. he command not the trim but trigger the autotrim system (that's not a manual command on the trim)
If for some reason .. the command to elevator is blocked (or the elevator is mechanically blocked) the pilot have no more control on autotrim
In manual the pilot can command the elevator and the trim (they are no more linked by a system)
So he have full authority on the two separate moving surfaces
He can even don't use the elevator for control the pitch ....
So ... really it's my aircraft

HazelNuts39 11th Aug 2012 12:17

I wonder if the preoccupation of some posters with the THS can be traced to a misperception of its rôle. When releasing the stick in a small airplane, the elevator is released and the airplane goes to the AoA for which it is trimmed.

That is different in a FBW airplane. Releasing the stick does not release the elevator. The elevator goes to the position that will provide 1g. As long as the elevator doesn't reach full travel, the position of the THS is irrelevant for the flight path. The main difference is that the elevator moves quickly and the THS moves slowly. 1° of THS is equivalent to 1.5° of elevator (according to Owain G).

syseng68k 11th Aug 2012 13:03


Not so simple if the pilot isn't used to it, as studi points out.
Well isn't that what training is supposed to do ?.


Manual control does not necessarily mean manual trim, no matter if you or others wish it was so.
Yes, (sigh) we know it isn't at present, but that wasn't the context. The
context was the suggestion that it might be a good idea. Comments on
what was actually said might be usefull. Like, for example, whether you
think it might be a good idea and if not, why ?...

NeoFit 11th Aug 2012 13:09

The pilot and the dog
 

The pilot's only job is to feed the dog and keep him awake; the dog is supposed to make sure that the pilot doesn't touch anything.
Hello gentlemen,

Sunday is coming, and I need some smiles.

It has been recently discussed here (AFAR) what the airplane's computers were doing.
Sometimes, Buses pilots are asking: "what 'she' is going to do"
(I don't need to open here a polemic about male or female computers).

So I propose you, for those who would not have made it yet, to acquaint with this.

If you agree, I'll speak another day about 'The bumblebee does not know how to fly ...but ....'

syseng68k 11th Aug 2012 13:14


If you don't understand, likely you never will.
Do you really have to be so superior and dismissive of others, or
is it just a temporary aberation ?. You're letting the side down
with comments like that and are starting to look like a troll, which
a usenet forum would have a particularly harsh way of dealing
with..

It's not a competition here :-)...

Linktrained 11th Aug 2012 17:15

NeoFit
Thank you for publishing Prof.Dr.Ronald Schmid on Computer in Command.

I would add that an aeroplane is the only mode of transport that is unable to stop whilst in its operating medium ( the air).

The Titanic, could have, should have, stopped. A car cannot be driven in practice on ordinary roads at speeds of only between 30 to 35 mph constantly, without having to stop, somewhere.

roulishollandais 11th Aug 2012 18:11

@ Dozy W.
Air Inter Ste-Odile:
If Airbus and Honeywell have changed the display FPA / VS on the FCU panel this results from their free choice, not a Court decision.:=
Instead the prosecutor, in his submissions on appeal, has completely rejected all attempts by experts and all parties to the trial for fifteen years who sought to challenge both the display, the autopilot modes, or that the control laws (not mentioned).
If the charges to be reviewed has not been decided by the Court is that the defendants were not for those wrong approach cards, and not for compensation ground.

Posts of the thread AF447 PPRuNe are not journalists or gossip grand public, but the result of discussions and information done by professionals.

TTex600 11th Aug 2012 18:50


Originally Posted by DozyWannabe

Try "thoroughly fed-up cop".

Then why continue to escalate the tension, especially by butting into a sub discussion that didn't include you in the first place? For that matter it's a free forum, you're obviously free to butt in anytime you want, but you could at least butt in as a third party instead of assuming the argument was originally made to include you.


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