I bet there were a few " merde's" being thrown around !

shogan1977

Nice, I agree. I know nothing about the Airbus, is there any indicator readily available to the pilots to show what angle the stabiliser is at ? Is there any way of trimming the stabiliser really "manually" ?

Shogan1977

I prefer to see facts rather than claims in a self serving article (lawyereese speak)

The above is nicely laid out to assess blame before the report is finished.

Such words as culpability have no meaning without examining all facts

Also I really don't understand how one can assign a regulatory word of "catastrophic" to a single system manufactuer such as "Thales". The presumption should have been a simple failure condition (if operated outside its certified enevelop) to be accomodated by the installer (Airbus)

Good point, the old 707 had two dirty great 'coffee grinder' wheels on the sides of the central consol, so that the pilots could really 'manually' trim the stabiliser should it decide to do something one didn't want. Sometimes one had to relieve the airload on the stabiliser by pushing the nose in the opposite direction to that desired, then when the pressure was reduced cranking the handle like mad in the desired direction. In this context the pilots may have had to pull the nose up even further momentarily of course to operate this truly manual method.

There was also a pointer which moved along a scale, so that one could see what angle the stabiliser was at.

Course it's all computerised now, therefore far superior, so nothing can go wrong, go wrong, go wrong.

Hi,

Same for Airbus

Answer was already posted somewhere in this forum (with pics)
The answers are YES for the two questions.

To ExSp33db1rd

Same system on A320.
Of course normally the AUTO-TRIM does it automatically, but you can do it manually with the wheel IF NEEDED.
The angle is also indicated

There are two PITCH TRIM wheels on the mid pedestal. They have scales to set the CG for take-off. Inflight the CG scale is not valid but the indicator shows the position of the THS (trimmable horizontal stabilizer).
The THS is only controllable manually when on ground or when inflight in direct law. In direct law one uses the wheel to trim the pitch manually - therefore USE MAN PITCH TRIM is displayed on the PFD.

Oooops: two've been faster...

So if the THS is 13 deg up and the sidestick held fully forward, will the a/c recover from the stall?

Hi,

Add to your question the AOA angle .. the air speed and the altitude of the AC ... as it can be important to know the outcome ......

Does this mean they would NOT have been able to trim the pitch in Alternate Law?

Assume sufficient height for recovery - the question I am asking is that with the THS at 13 deg up and the side stick held fully forward and the engines at idle thrust (which they were) is the stall recoverable? What difference would positioning the THS fully forward make?

Hi,

This mean that they were able to use manually the trim wheels
The manual trim is available under all laws

Hi,

Undoubtly a big difference but keep in mind the AOA and air speed factors.....

jcjeant: "The manual trim is available under all laws"

DouglasFlyer: "...only in direct law..."

Who should I believe? :confused:

Hi,

In its conclusions the BEA makes no allusion to the pitot tubes to justify the inconsistent speeds

What would happen if a high speed upwind (possible bad weather in area) of + - 100 Km / h met the static probes ...
That will he not cause a significant decrease in the indicated airspeed .. and this does he not bring up the plane very quickly?

As with ExSp33dblrd reply for a B707, manual cranking of a TP trim wheel can be arduously slow, on some craft there is an electric trim motor (B727 example) which does this work much quicker, how about on the A330?

Hi,

Check this !
http://www.smartcockpit.com/data/pdf...t_Controls.pdf

Also:
http://img402.imageshack.us/img402/8669/thsinfo.jpg

It adds nothing to the discussion but some highly tendentious speculations...

As far as we can gather from the report, at least initially not the THS forced the plane nose up, but the stick input did.

2h10m51:
Stall warning
(...)
PF maintained nose-up inputs
(...)
The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute
(...)
The PF continued to make nose-up inputs
(...)

2 h 11 min 40:
The PF made an input on the sidestick to the left and nose-up stops, which lasted about 30 seconds

2 h 12 min 02:
Around fifteen seconds later, the PF made pitch-down inputs. In the following moments, the angle of attack decreased

This is the first mention of any nose down input after the stall warning, 1m26 later. It is not known how long this input lasted (and BTW it is also not known whether PF ceased the ND input due to the reactivated stall warning, as many here claim).

We don't know that. The report states merely:
simultaneous inputs by both pilots on the sidesticks were recorded

Report says: and the PF said "go ahead you have the controls".
Admittedly probably not dramatic enough for a "serious" publication.

Which would necessitate a continuous downward acceleration. We know downward velocity at 2h11m40 to be -10000 fpm, final velocity at 2h14m28 to be -10912 fpm. :(
They appear to have reached terminal velocity pretty early on.

Passengers held in their seats!
 

Quote...

The passengers, who had just a short time before been pressed into the backs of their seats, were now being held into their seats only by their seatbelts. "At this moment, I would have feared for my life even if I was sitting in the passenger cabin," said one A330 pilot after reading the BEA report. That the plane was in freefall would have been clear to all on board. The nose of the plane pointed skyward at an angle of 16 degrees. "That's more than immediately following takeoff," the pilot said.

Unquote.

Having flown many times and thinking about my built-in senses of horizontal and gravitational, I tend to agree. To me the unanswered question is then - why didn't the pilots realise they were pointed up towards the sky and they were falling like a leaf? They could see the altitude bleading away extremely rapidly. Could they not read the attitude also? At least they knew they were pulling up!

REALLY, did they think they were diving! Continuous efforts to pull up over more than 2mins had resulted in no reduction in loss of altitude, so why didn't they realise they were "going down backwards" - well, almost. It seems ridiculous in hindsight that pulling up over that length of time and not reducing the descent MUST only mean you are not diving, you are stalled. Easy to say now, but those guys are supposed to be professionals, yes?

A major contributing factor must be the 13 deg THS trim. I know, if you pull up continuously you will get the THS auto trim as well but for the autotrim to then later give up and LEAVE the aircraft in this trim, ESPECIALLY if pilots are trained NOT to touch the trim, is "less than desirable" IMO (mildly). Surely a recommendation needs to come from this unfortunate part of the control setting, either re-trim back to neutral when giving up or make the pilots check the trim wheel = SOP/training. Not the first time (Perpignan), lets make it the last.

Hi,

And we don't know if the vertical stabilizer angle changed during those pitch down inputs ...
We only know it changed when it was pitch up inputs.

Thanks Zorin75 - Your clarification is well taken and duly noted.