Is this a trick question? :)

The position of the sidestick(s) and its view from seat #3 appears to becoming an issue judging by posts in the last couple of pages. As previously noted many posts ago, the sidestick position is displayed on the PFDs when in the WoW mode.

If displaying the the sidestick position following an AP disconnect is adding too much clutter to the display, then displaying it when loss of airspeed data due to NCD occurs might be a good get me home option.

In the same situation displaying the mean AoA value plus the THS position would save one from making the, "No valid indications" comment.

OK - that's one vote for a 'sort of inertial' system and one that appears to not understand what the question means. - I'll take you up on that - do you perchance have a system diagram showing inputs to the THS system that I might learn from?

- no you may not since you do not understand the significance of the word 'lock'. I'm not sure whether that is a language problem or if you fly the a/c but do not understand it properly (as fantom said in his now 'disappeared' post). In English 'lock' means to secure something so that it CANNOT EASILY BE MOVED - as in the Airbus.

If I could have a definitive answer that will not be challenged two pages later by someone else I can move along.

That may indeed be a language problem being not a native speaker although I generally do understand what 'Locked' means.

However I did not take it literally as 'locked' in that paragraph, more along the lines the THS being at +8° (e.g. due to Auto Trim deactivated, so unless manually moved it will simply stay there but not being mechanically arrested in any way).
Bear in mind Airbus is a Company with a lot of French influence/origin, thus English documents may deviate slightly from the original French ones from time to time. My feeling is you might be over- interpreting something in their Language.
Do we have any indication that there is a possibility to literally lock the THS (in the sense you took it) ?

Hi BOAC,

I think you'd enjoy the course.

The ADC input will modify the elevator movement. The stab will be autotrimmed so the elevators return to their neutral position.

http://www.merrowresidents.org/pprune/Stabtrim.jpg

Thank you rrat - I'll wait a couple of pages and see if anyone else interprets the 'ADIRU' input differently. Are you saying, then, that a low 'detected' IAS will increase effective elevator 'gearing' which will produce a greater THS follow-up movement?

henra - it has been stated that the THS locks in one of the failure modes - ie autotrim ceases to function. Regarding 'translation', I feel that if FCOM Vol 3, Supplementary Techniques, Flight Controls, Flight Mode. (3.04.27 P3) did not mean 'locked' (in English) then it should say so?.

BOAC;

Could I put it this way -

The only known method of locking the THS position is to hold on to the trim wheel. So if the THS is > 8 degrees and held, the elevator may not be effective at more than 180 KTS.

Hi BOAC,

The "gearing" "Q pot" etc. is now done via the ADIRU input. It would probably feel "twitchy" if the real airspeed was greater than sensed. However, the elevator position to hold a given attitude would be the same and hence so would the trim position.

Hmm maybe we still have a different notion of the word 'locked'.

I understand that in Abnormal law as well as in Direct law Auto Trim is lost/disabled and the THS will stay in the last position unless manually manipulated by the Trim wheel.
However, I'm not aware that there is any kind of blockage/hindrance against manual operation of the Trim. Just the system won't do it for you any more automatically. Effectively you change plane from A to B.
Also the schematics which have been posted point in that direction.

You are trying really hard not to fall off the outrage express, aren't you BOAC.

As any other mechanical system a stabilizer can become locked, blocked, jammed, immovable, seized up........Should I continue?

http://img219.imageshack.us/img219/9...abctlfault.jpg

Just remember I did not write the word 'locked' in the FCOM please.

KBP - many expresses do not stop until they reach destination. So, for 'lock' we now read 'jammed'? Nothing to do with the cessation of removal of autotrim function. My goodness me, that took a while, but I think I saw a train approaching the station.

FWIW, wrt the visibility of the THS indication and the F/O's sidestick, two views of the cockpit - Daytime, A330, night-time, A340:

http://www.smugmug.com/photos/i-bJvf...-bJvfTcP-L.jpg


http://www.smugmug.com/photos/i-WJNx...-WJNxHQf-L.jpg

@ BOAC and others:
 

I did try to clarify to prevent discussion:

But I get the impression I failed..........

This remark is given in the mentioned FCOM 3.....when a FCTL STAB CTL FAULT is present. This was for sure NOTthe case here. The THS was free (NOT locked) to move Airplane Nose Down.

What it will say is that full elevator authority alone is not sufficient to counteract the PITCH UP THS position if this is > 8 ANU and if Speed > 180 Knots.
If THS <=8 ANU the elevator deflection alone can counteract a THS 8 (or less) ANU position.

If SS input was FWD the THS would have followed the command as designed.

@ BOAC:

The FCPC gets ADR & IR information to compensate for speed.
The IR part can't be compared to the old INU systems, this is very precise accelerometers and 3 axis ring laser gyros equipment and yes the crew is allowed to have a peek on the same signals through its PFD.

There is an interface with ATA 76 (engine controls) but these are discrete signals only and used for ground spoiler logic(T/L position), for 3rd T/R lock release and for limitation of the green servo control speed in case of a dual engine failure.

@CS:

Maybe you have better eyes then me, I need periscopic glasses to do it without interfering the guys on P1 or P2.

PJ2,
Thanks for your answer. Then, there is perhaps a (remote) possibility that a PNF could suspect inadequate pitch inputs by the PF by noticing from the corner of an eye the trimwheel moving in an unexpected way. This is probably irrelevant, however, in a tight situation.

What factors do the designers consider when setting out how far the THS can travel ? Would it have mattered much in real life if it had been limited to less than 8 degrees NU ?

@ somebody who asked manual pitch trim rate.
 

One stroke on the Trimwheel ~0.65° THS movement. (2 hydr. motors B+Y available)

DJ77;
Re your first statement, in a word, yes, I think it is possible to put together a THS wheel rolling aft out of the corner of one's eye while observing the pitch increase and the inappropriately high vertical speed but it requires a calm eye in the face of the unfamiliar and a habit of not focussing on the same thing as the other crew member. I think there's more than that: Listening to that "sixth sense" would be part of it... the fact that the air noise begins to go a LOT quieter when the pitch is still high, one begins to slowly, gently feel lighter in the seat and one can begin to actually hear the engines, as well as paying attention to whatever it is in one's belly that says things aren't good. But I think your second statement applies as well.

So if trim is sitting at 13 degrees aircraft nose up direction and you need to get it down to around 4 degrees ANU to recover, it would take 13-14 strokes on the trimwheel.

Anyone have an idea how long that might take to execute? Does trim wheel motion keep pace with the THS position on its way down to reduced trim or can it get out in front of it and let the tail catch up?

Control stick, AoA, autothrust in lites
 

Salute!

Thanks to EMIT, thanks.....

- The transition from a big stick or yoke to the "force" transducers was very easy. Like about 3 or 4 seconds on first flight. Put some pressure on the stick and the jet moved ( rolled or pitched). I flew with many fossils and newbies in the family model, and that was my experience when letting them fly.

- The family model sticks "added" the command for roll and pitch, and we could not see the other guy's inputs, nor would it have made any difference. as the stick didn't move more than a few millimeters. So I could 'help" the newbie, but if I let go he would wonder why the jet was trying to climb a bit on final approach.

- I flew three jets with the AoA indicators. The two that counted were the SLUF and the Viper. The SLUF was a Navy variant and had the "indexer" lights up on the glareshield, or on one side of the Head Up Display. This allowed us to fly the optimum AoA on approach without calculating weight versus speed. AoA is AoA, regardless of your weight.... duuuuuh. We still had to do a rough, rule-of-thumb, correlation of our indicator with the airspeed we expected. This was due to leading edge flaps that allowed a higher speed for the same AoA and other factors. Nevertheless, the Navy folks here can tell ya about the AoA "indexer" lights.

- The Hornet has an "autothrust" feature. Only did a few approaches in the sim, but I basically used pitch for AoA , and let the motors handle the vertical velocity part of the function. Not sure how this works for the heavies, and I really didn't find the feature all that neat. I preferred to trim for the AoA and use throttle for descent. I also had the neat HUD flight path doofer to see where I would impact if I didn't change anything. Saw it first in 1971 when checking out in the SLUF, and it was a real treat.

As another contributor has stated, wings provide lift according to AoA and "q". It's the same for a 'bus as for a Cessna or an F-22. I do not advocate yet another indicator in the cockpit, but for approaches an AoA indicator could be very useful. OTOH, when near a stall or actually in a stall, the AoA indicator is of extreme value.

One of these days I can digitize my HUD video of the leading edge failure episode. The flight path marker really helped me, as the bird was yawing quite a bit, reacting funny with roll inputs ( all 1 -2 pounds of available command authority) and you can see my goal - 1,000 feet down the runway!

from the high mountains in Colorado, I comment, read, and learn from my fellow pilots flying vastly different aircraft.......

Hi,

From the Rumours and News:

BEA
http://www.pprune.org/rumours-news/4...ml#post6558788

When PF make nose up stick inputs the THS follow .. and when PF made nose down inputs the THS don't follow
Why :confused: