Well, I should have read this report about 20 times now, in French and English and I certainly do remember it.
Now, this come at 0212:02 + 15 seconds... more than 2 minutes after the begining of manual flight. At this point, I would expect something like:
"The pilot made pitch-down imputs to the stops during 1-2 minute(s)" not "the PF made pitch-down imputs" (how many, how far, how long?).
I'm not sure that it is showing that the PF had fully realised the situation at this point (and I believe he did not).
Nonetheless, despite having a THS trim at +13 deg and being already in a full stall situation, it seems that those imputs are effective by reducing the AoA... hence, elevators were still effectives, don't you think?

Lack of stall signal was the reason for the crash
 

My two cents...

.... once the plane stalled, why the pilot acted as he did:

The plane is losing height at 10912 ft/min. The pilot have to determine if the plane is:

1) Diving (then apply UP elevator)
2) Falling down in deep stall (then apply DOWN elevator)

The pilot knows the stall warning is the most important warning there it is.
...BUT... THERE IS NO STALL WARNING !!! ... so the pilot assumes the PITCH indicator that points to nose up attitude is WRONG!

He has two mutually exclusive indications:
1) PITCH UP
2) LACK OF STALL WARNING

The pilot choose to believe that if there is no stall warning, there is NO STALL, the pitch indicator has gone bad and the plane is in deep dive. Therefore he will PULL UP. No other crew member corrects him, because they all think the same. If any one believed they are in sustained stall for 2 minutes, they will be crying "STALL, PUSH DOWN" and not be mostly quet.

At one moment, the pilot pushes down the stick, the plane starts to recover and .... THE STALL WARNING COMES ON !!! So, the pilot is warned that his action CAUSES STALL. Being in confused state due to conflicting information, he goes back to pull from deep dive and all other pilots agree to the end...

Here is what BEA report says:


During the following seconds, all of the recorded speeds became invalid and the stall warning stopped.

Note: When the measured speeds are below 60 kt, the measured angle of attack values are considered invalid and are not taken into account by the systems.

In my opinion, this is design problem that lead to the crash:

The fact is, during the 3 minutes descend while the plane was falling at 11000 fpm THE STALL WARNING WAS QUIET. If the stall warning was ON, the pilots would take the correct action to lower the trim, push down the stick and save the plane (if physically possible).

Here is the relevant text from BEA:

At 2 h 10 min 51 the stall warning was triggered again. The thrust levers were positioned in the TO/GA detent and the PF maintained nose-up inputs. The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight. Around fifteen seconds later, the speed displayed on the ISIS increased sharply towards 185 kt; it was then consistent with the other recorded speed. The PF continued to make nose-up inputs. The airplane’s altitude reached its maximum of about 38,000 ft, its pitch attitude and angle of attack being 16 degrees.

Note: The inconsistency between the speeds displayed on the left side and on the ISIS lasted a little less than one minute. At around 2 h 11 min 40 the Captain re-entered the cockpit. During the following seconds, all of the recorded speeds became invalid and the stall warning stopped.

Note: When the measured speeds are below 60 kt, the measured angle of attack values are considered invalid and are not taken into account by the systems. When they are below 30 kt, the speed values themselves are considered invalid.

The altitude was then about 35,000 ft, the angle of attack exceeded 40 degrees and the vertical speed was about -10,000 ft/min. The airplane’s pitch attitude did not exceed 15 degrees and the engines’ N1’s were close to 100%. The airplane was subject to roll oscillations that sometimes reached 40 degrees. The PF made an input on the sidestick to the left and nose-up stops, which lasted about 30 seconds.

At 2 h 12 min 02, the PF said "I don’t have any more indications", and the PNF said "we have no valid indications". At that moment, the thrust levers were in the IDLE detent and the engines’ N1’s were at 55%. Around fifteen seconds later, the PF made pitch-down inputs. In the following moments, the angle of attack decreased, the speeds became valid again and thestall warning sounded again. At 2 h 13 min 32, the PF said "we’re going to arrive at level one hundred". About fifteen seconds later, simultaneous inputs by both pilots on the sidesticks were recorded and the PF said "go ahead you have the controls".

The angle of attack, when it was valid, always remained above 35 degrees.

I would also presume it is a coincidence, but ...

There is something to be clarified here :
At takeoff the CG was pretty much forward around 23% which makes sense considering the heavy cargo load.
The estimation made by the BEA initially put the CG mainly aft around 37% at the time of the upset. But now the data tells it was at 29% only ...

Absolutely, even if at time, like PJ2, I can feel a bit irritated by so many posts that may look as a waste, but to discard them of course you need to read first ... I have also no doubt I can irritate many myself.
Never mind, it is just question to let the storm go and already after 3 days things are cooling down, more constructive stuff can take place already.

Some even pretend the only 'knowledgeable' is the BEA, on which I fully disagree. In this time of INTERNET, full data should already be in the public domain, BEA itself would probably also gain something from it ...

Takata
Absolutely yes, but they ran out of authority against that great big THS. If the THS had been set to a lower value at that point, it appears the aircraft would have continued rotating until its nose pointed down the velocity vector. We don't yet know how long the nose down input was held, do we? Only that it brought on the return of the stall warning.
The stall warning may have stopped the crew's nose down input, or maybe it didn't. Probably it was a matter of authority. BEA hasn't told us yet.
The crew was evidently trying everything they could think of, they just didn't think of the manual pitch trim because at some level they probably considered it irrelevant. That is what training needs to fix.
So how easy would it be to fly a right wing heavy A330 in Alt 2 law in your estimation? Could you keep from applying aft stick if flying with your right hand?

THS inputs
 

Interesting post yesterday from Jcarlosgon

I was kindly allowed an extra exercise at FL350, about 170 tons, CG around 30%, about one year ago. Pull up from FL350, all 3 ADRs off, kept it at 15 degrees up till it stalled, à la B707/27/37, A310, in gone years.

THS went full back, don’t remember the figure, and sidestick was released, N1 at 85% (A/THR off). The nose came down to about -5 and went back up to +10. Rate of descent was between about 6K fpm and zero, or slight climb (sim is an A330 with PW engines, 85% is slightly above needed N1 for turbulence at M 0.80).

Not a Bus operator myself, what causes THS to move? Is it only pilot inputs from the trim button on the stick, or does the computer tell it to move?

Could it be that the pilot inadvertantly thumbed full nose up, while gripping the stick. I suspect that the audio of trim movement could well have been lost among other warnings sounds, and once trimmed full back, recovery would be almost impossible, unless trimmed back the other way.

Given all that was going on, white knuckles on the stick would not surprise me one little bit.

OK, Conf iture, I went back and removed the MAC from the post. Thanks for the important clarification. 29% MAC is not near as serious as 39% when it comes to stall behavior and recovery.

I still think it is possible they dropped like a skydiver without a parachute.

Hi,

Methink it's not "thumb trim button" on stick and methink movement of trim wheel is soundless.(that's not help but is how is that in Airbus)

Beachbunny, it isn't what you think. The A330 is a Fly By Wire aircraft and is is designed to autotrim itself in pitch and roll. There is no trim button to accidentaly displace. If I remember PJ2's briefing correctly, the THS trim wheels move silently in response to automatic trim inputs. The THS trim is controlled by Prim computers, any one of the 3 can do it. If the Prim computers are inhibited in some way, or if certain protection features are activated, the trim doesn't move. To understand this takes familiarity with the flight control laws. You will have to break out the books, I'm afraid, to hope to understand what happened.

Is it true that Airbus is "flight path stable", as opposed the FBW B777 which is like conventional aircraft "speed stable? This is an important distinction in that the B777 requires pilot input on the pitch trim to establish a speec, where a Airbus pilot sets a flight path he wants and uses auto-thrust or manual thrust to set or maintain an indicated airspeed. The two premises result in quite different handling characteristics.

Not a 'Bus pilot

THS
 

Thanks for the reply, Machinbird.

That sounds real scary, if the pilot cannot control a primary control surface.
Surely there would have to be some way that it could be re-positioned during hand flying????

Mechanical trim can be used once the auto-trim is no longer available or the pilot overrides the auto-trim - however once in mechanical trim there is no reversion to auto-mode. That is a ground reset function.

28 October 2009 - VH-EBA - Airbus A330-202
 

The only relation this incident has to AF447 is that the aircraft was an A332 and UAS was due to ice in the static port. A stall warning did not enter the equation, but similar warnings were generated. The crew followed the QRH and the graphic below shows the outcome.

http://oi56.tinypic.com/24phoxk.jpg

The dip in altitude is not real, and for an explanation see the ATSB Report.

NB The graphic above is larger than that published in the report.

Abnormal Law Warnings or Messages?
 

Takata wrote that the plane would have kicked into Abnormal Law due to AoA and speeds:
Sorry in advance if this has been asked and answered before, but:

• If/when the plane kicked into Abnormal Law, what warning or message would have been visible or audible to the pilots?
• Why was the transition to Alternate Law indicated in one of the ACARS messages, but no message about any other change in Law?

Thanks

Hi,

Dunno if this was already posted here ...
Interesting anyways (even as reminder)


Remove the spaces

Was in 2006
By Joelle Barthe
Flight Operations Engineer

falcor

Have a look at A340 / A330 Control: flight & laws

IAS at 40 degrees AOA.
 

I don't think any pitot tube will produce a reliable output at extreme AOA's.

That AF note says that, in the event of an Unreliable Airspeed Indication (plus a few other similar events):

- Above the safe altitude, whether in the climb or cruise, maintain the given pitch and thrust settings, then work the UAS Checklist without applying the UAS Emergency Procedure;

- Below the safe altitude, apply the UAS Emergency Procedure.

So the questions are, a) what was (in June 2009 when the note was issued) the USA Emergency Procedure, and b) does the new BEA note give any indication that the PF used it, even though he was in the cruise, and then in a climb?

We do know the a/c did not maintain given pitch and thrust; we do not know if the crew worked the checklist.

mm43, re VH-EBA UAS:
The report states that this short UAS event was due to pitot icing (impact pressure lost), not the static port.

Abnormal Attitude Law
 

Hi,

Once the aircraft was in Abnormal Attitude Law (with IAS less that 60 kts or angle of attack >30degs) can anybody point me to an FCOM reference which indicates that "Use Manual Pitch Trim" would (not) be shown on the PFD (as in Direct Law)?

Thanks.

A few points:
Pitch Trim is always available to the pilots (save double Hyd failure).. just move the wheel and overrides all FBW. However, you'd have to be pretty confident / assertive to do it outisde Direct Law, not part of the training (save one exception discussed above for some operators).

Stalling - the training/understanding of airline crews is infrequent and limited in scope. SOPs / monitoring and warning systems are designed to warn of, and recover from at the approach to a stall. Expecting crews to comprehend what goes on beyond the stall i.e. IAS <100K AoA 40deg+ is unrealistic. Who knows even how far the certification went in this regard?

Please NB 2 x 757 also complete loss with UAS and the confusion that reigns over contradictory wearnings / instruments. As an industry I would not say we are much advanced from that point. You might just see a fair performance in the sim (and is the sim model correct? unlikely) in a "set" training package - to see that replicated 2-3 years later, at night, circadian low, with no warning I think unlikely to see a good % of well handled recoveries :sad:

Think where the industry is going. We could easily have only a cruise co-pilot on the Flt Deck (other pilot on a comfort break)... :ooh:

again...... have a look at figure 6 in the this paper from BJ-ENG....

http://ntrs.nasa.gov/archive/nasa/ca...2005208658.pdf

but a CG at 29% is much better than expekted

BEAs statement is a careful selection of established facts which must have been checked out carefully by legal opinion - so I think I think it is worth looking carefully at the words used - albeit in the English translation - does the French read the same? Maybe reading in too much?

Suggesting he was asleep, and could have been for a couple of hours - but within 5 minutes he was in front of the controls as PNF.

that was nice - he could have just said bye? OK a lot more would have been said in the 3 minute handover, but who was Responsible, Accountable, or just Consulted/Involved. (yes management consultant speak - RACI analysis).

PF said shows he knows near max alt, and not authorized to climb, and that they all knew that.

tentative subservient, he didn't like what he saw ahead.

Repeating a comment in this thread too many pages back. PNF not happy with what PF is doing - but doesn't have authority to question?

Did they tell the captain that they had been to 38,000 ft and were now on the way down?

Better WXR Training Needed?
 

Honeywell: Better wx training needed
Radar manufacturers should consider making equipment easier to use and displays easier to interpret, Honeywell safety specialist Dr. Ratan Khatwa told attendees at this year’s Flight Safety Foundation European Aviation Safety Seminar, held in Bucharest.
He added that better weather-radar training can improve pilots’ awareness and decision-making skills and help them avoid penetrating severe meteorological conditions.

NTSB studies show weather to be a factor in about 25 percent of all U.S. flying accidents between 1994 and 2003. Khatwa said initial and recurrent flight crew training should cover fundamental concepts in six areas of weather-radar operation: beam coverage, Earth-curvature effects, antenna stabilization, tilt and gain management, calibrated weather and range. System limitations, such as attenuation and the significance of green radar “echoes” at high altitude, also should be covered.

These recommendations arise from analysis of pilots’ difficulties and concerns uncovered while Honeywell was developing its RDR-4000 radar. Khatwa’s study included a human-factors evaluation of flight-crew radar use, a global survey to assess pilots’ fundamental understanding and perceptions of training, and analyses of weather radar-related incidents and accidents. He concluded pilots did not understand fundamental weather-radar concepts; typical equipment use precluded detection of severe weather; and dedicated training was not standard practice.

Khatwa pointed out that current radars are concerned primarily with weather analysis and avoidance, proper interpretation of which depends on pilots’ adequate understanding.

Honeywell’s RDR-4000 human- factors research showed that almost 70 percent of pilots were dissatisfied with weather-radar training. From the survey, Khatwa concluded most operators do not provide initial or recurrent weather-radar training; most available training takes place on the job; there is little incentive for operators to provide training since regulators do not require it; many pilots do not understand weather radar, including its limitations; fundamental concepts of weather radar are “poorly understood”; and pilots want recurrent training.

To understand pilots’ weather-radar use and any difficulties, Honeywell conducted a comparative evaluation of independent flight-crew groups using current equipment or new radar-display modes. The PC-based exercise observed the behavior of 13 pilots during several scenarios involving weather-radar use. Overall, “significant weather” events were detected on almost 82 percent of occasions, with pilots correctly deciding on action necessary to avoid penetration 70 percent of the time.

Incorrect pilot action involved improper management of weather-radar tilt, gain or range, continued flight toward significant weather and imprudent weather-avoidance decisions. All pilots failed to recognize the vertical position of each of two weather cells. Khatwa emphasized the need for pilots to be cautious about green radar echoes at high altitude, since these indicate “potentially hazardous” conditions.

Analysis of actual flight-crew radar operation and interpretation was ultimately restricted because the study could not include “many other critical factors, such as provision of timely weather information, accuracy of such data, role of ATC and regulator” and other considerations. This part of Khatwa’s study drew on data covering fatal and nonfatal accidents and incidents (fixed- and rotary-wing) that involved global single- and dual-pilot business, public transport and cargo aircraft operations reported by nine different worldwide safety agencies between 1987 and 2007.

Excluding occurrences involving training flights, sabotage, terrorism, military action or insufficient weather-radar information, Honeywell researchers found just 14 relevant events. A quarter of these instances were fatal, and half of the aircraft involved were substantially damaged or destroyed. Some 57 percent of the accidents or incidents took place in instrument meteorological conditions, 50 percent occurred during cruise, the same proportion was in daylight and another 35 percent occurred between top-of-descent and destination.

Switching off the radar, despite forecast weather and prevailing conditions, or pressing on in the face of adverse conditions were cited as examples of poor planning. Other examples of poor decision making included making landing decisions based on the experiences of preceding aircraft that successfully penetrated convective weather; flying through gaps between closely spaced storm cells, rather than around the thunderstorm; and flying close to squall lines.

In addition, the operation of weather radar or radar-display interpretation were “not necessarily optimal” in two thirds of occur-rences, said Khatwa, who cited five problem areas: improper tilt operation or management; improper use of gain control; misinterpretation of ground returns; weather radar “off,” despite known cumulo-nimbus cloud; and insufficient appreciation of radar limitations and their impact on displayed images.

The Honeywell study shows that crew weather-radar training had not been provided in half of the accidents/incidents. Pilots talked about “trial-and-error experience” and “information [obtained] from other pilots,” an approach that Khatwa concluded can “lead to improper radar operating procedures and techniques.”

Honeywell Aerospace Pilot Survey Findings

In conducting a survey about the RDR-4000 weather radar, Honeywell safety specialist Dr. Ratan Khatwa asked more than 50 ATP-rated pilots about their experience with weather radar. The average age of the respondents was 52 years; the average flight time was 12,500 hours. The answers these experienced pilots provided were illuminating.

• 62 percent of the pilots surveyed answered correctly that a straight radar beam is not aligned with an aircraft’s current flight level (because of Earth curvature)

• 15 percent mistakenly thought that antenna down-tilt was required to offset a nose-up pitch angle. (That is offset by antenna stabilization.)

• 63 percent did not appreciate the need for weather-radar antennas to be set to compensate for earth curvature, which blocks weather targets beyond, say, 150 nm ahead for nominal cruise altitudes. “Curvature [effects] become noticeable at ranges above 40 nm, and if ignored can lead to weather-image interpretation errors,” said Khatwa.

• 55 percent of pilots did not realize that a weather target falling inside the radar beam will not necessarily be shown in its true color on the display. “The color selected for display is a direct function of the power returned to the receiver. Where the beam is partially filled, the total power returned may not represent the calibrated value associated with the target cell,” he said.

• Five in every eight pilots incorrectly thought green (short-range) radar targets shown near to cruise levels above FL310 need not be avoided. “Typically, at these altitudes, targets are less reflective. At high altitudes, there is a possibility of unstable air and hail above the storm cell. It is therefore not advisable to penetrate the less-reflective part of the storm top,” Khatwa explained.

• 73 percent of flight crew understood that antenna tilt angle does not need to match a climb (or descent) angle to detect weather on their flight path. “The antenna should be pointed at the base of convective weather during climb. Generally, the lower 18,000 feet is the most reflective part of the storm.” Radar can be used to analyze weather characteristics (such as vertical extent of cells) and to avoid strong convective activity. “Returns along the flight-path angle may not provide full indication of storm intensity and turbulence levels [to be encountered within the cell].”

• Almost 90 percent of pilots did not know the range at which their current weather radar was no longer calibrated and did not show returns at their true levels. Radar beams broaden with distance, so a smaller proportion is filled with moisture. “At shorter ranges, returned power is more representative of the target cell, and it is more likely to be displayed at its true calibrated value. Typically, returns are calibrated within a range of 60 to 80 nm.”

sensor_validation
 

From a human factors point of view, I'm with you on that.

How can a guy be woken up at 1:55 and at 2:02 be in charge (albeit as PNF) of the A/C, whatever the briefing he has been given ?
When s..t hits the fan 8 minutes later, I am pretty sure that the poor guy was not totally up to speed.

Except in the “New findings” part at the end, the BEA update report is sliced into paragraphs that start with a time stamp. Each paragraph contains details like general configuration of the flight (e.g. speeds, AoA), sidestick controller inputs, audio alarms, tidbits of dialogue between pilots where and when BEA thought the information significant. Clearly what is exhibited in each paragraph was observed between the initial time stamp and the time stamp of the next paragraph.

With this in mind and noting that between 2 h 10 min 16 and 2 h 10 min 50 (citing the report) “The PF made nose-down control inputs”, I venture to submit that it is quite unclear what exactly caused the zoom climb to 37500 ft and this is a hint that BEA intends to closely examine this point.

Whether it was pilot induced or something else, this phase of the accident played a major role in establishing the confusion that followed.

A sleepy PNF is better than none I assume?
 

Rather than worrying about the state of the PNF, if we are going to read things literally then 'THE PILOT woke the Co-Pilot', not "had him woken" so it is a good job this did not all happen at 1:55am with just one pilot, one asleep and the captain out of the cockpit.

It seem illogical to criticise how awake someone is, when there are probably numerous occasions when you are happy to accept just one in the cockpit.

why coincidence?

what did you think how BEA create the 3D flight path picture (last 5 min of flight) in the report?

they know surely save the 3D pos of LKP and the 2D pos of the crashplace, and they have truly the acceleration X/Y/Z from the box, and a lot more information with more or less reliability,

they puzzle a line over the two save points and try to put in as much as possible of the information, always checking if it is plausible with the acceleration .....

and if the flightpath ends with 45 deg then the GS is alway equal VS.......

no coincidence


p.s. by the way, how did you realy manege the calculation of the flight path angle if all avionic people use feet in Z direction and miles in X and Y, did you first convert the miles in feet? or use a scaled chart? or exist a calculator with the tangentfunction (feet/miles)

RON51, TurbineD & that Trim Wheel
 

RON51 and TurbineD

Thanks, two worthwhile & very relevant posts a good few pages back (blink and we have another 5 or 10 new ones!)

One on the A330 TCAS zoom climb and the other on sensible software strategies

======= That Trim Wheel ================

Despite acknowledging the persistent nose-up control commands and their over-riding effect on the outcome, I still cannot avoid glancing suspiciously (in my mind's eye) down at that trim-wheel - and its 'apparent invisibility' - and too, its apparent culpability... almost 'by accident ' a dangerous approach to its presence, usage and modus operandi seems to have developed within AB and Airline SOP :sad:

What would the certificating and licensing authorities make of the (reported) 'slap wrists very hard if you ever touch it' mentality ?

Surely, that is why it has become 'invisible' as others have intimated earlier...

We really must focus heavily on HR (Human Response) issues - despite the weather, despite the icing, despite the UAS and despite initial AP/AT response (which perhaps was fairly benign, contrary to original speculation).

.. and on flight-crew selection and training.

Not true. When auto-thrust is turned off, the engines will adjust thrust to match the two thrust level symbols (blue doughnuts). In this case, the auto thrust likely disconnected in cruise while the thrust levers were set to CLB. Without a pilot action, this would cause the thrusts to be increased to CLB to match the thrust lever symbols.


EDIT: I TAKE IT BACK, CONF iture was correct.

What I wrote is true only for voluntary Auto thrust disconnect. In case of involuntary disconnect, the thrusts are frozen at the actual power settings

FCOM 3.02.22 Page 2

You are correct on that one. The old procedure called for the pilots to power himself out of the stall with minimal altitude loss. Nose down and power reduction were only to be used in a Note, if method one did not work.

So in this pilot's mind, both Unreliable Airspeed Drill and and Stall Recovery procedures would require power.

UAS would need nose up 5 degrees with CLB power while the stall recovery would require to maintain approximate pitch and TO/GA.

RON51 & TurbineD & HarryMan

More about that trim wheel visible to all 3 pilots in the cockpit ...

Post #502 (14 Mar 11) by PJ2 on the Tech Log thread gives very good background information for the Trim Wheel/THS discussion. Post #502 contained this image – now annotated with A the main trim wheel and B the vernier scale for the THS.


http://i31.photobucket.com/albums/c3...0_IMG_3037.jpg

Is this confirmed by any AF folks?

Rob21

In (American) aeronautical engineering English, incidence is the angle between the wing and the fuselage. With the exception of a very few airplanes, it is fixed. Angle of attack is the angle between the wing and the relative wind. I don't know the French phrase for angle of attack.

My mistake, "Incidence" in French is angle of attack...

The FCOM reference is 3.02.10 Page 10. I only have the 2010 version. Someone would need to dig up the old version.

Rob21

Also, according to the interweb, some Brit aeronautical publications reportedly use angle of incidence to refer to angle of attack.

AF "procedure anormale complementaire Stall warning"
 

Hi there
page 97 of http://www.bea.aero/docspa/2009/f-cp...cp090601e2.pdf
you will find the AF "procedure anormale complementaire Stall Warning":

during any other flight phases after lift off
Thrust levers.............................TOGA
Pitch Attitude............................reduce
Bank Angle...............................roll wings level
Speedbrakes.............................check retratcted

Hi Minorite invisible,

I have a copy of QRH 2006 for A320 series and there is NO Stall Warning procedure. The closest is "Low Energy Warning" which basically says:

"The Speed Speed Speed synthetic voice is triggered every 5 seconds , whenever the aircraft energy goes below a threshold under which thrust shall be increased to recover a positive flight path angle.
_Thrust Levers.... Push
Increase the thrust until the warning disappears."

The Stall Recovery QRH was introduced in May 2010.

Could the crew of AF447 have confused "Stall Stall" synthetic voice with "Speed Speed"?

Rubberband2,
It matters not how big the trim wheels are in real life. When you are trained to treat them as a piece of furniture inflight, it is effectively in the minds eye a piece of furniture and not the solution to "my" immediate flight control problem.
I believe I am in agreement with HarryMann on the importance of training to use this equipment so that it does not remain a piece of furniture. The control power of the THS makes the elevator into little more than a trim tab by comparison. (And I do have experience with flying jet aircraft with this control surface arrangement)