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-   -   TAM A320 crash at Congonhas, Brazil (https://www.pprune.org/rumours-news/284415-tam-a320-crash-congonhas-brazil.html)

Max Tow 3rd Aug 2007 13:42

James 7
Re your comment:
"If these items were not actioned then what else was not actioned
by TAM"
A little premature, I feel, unless you know something more. The SB was reported here as discretionary not mandatory and the MEL published by TAM does indeed show the instruction to set both TR's even if one locked (if that's what you mean by amended).
GD&L
Yes, but the alleged overrun T/L screw ups have been when one TR is inhibited - see BOAC's comment re a mental block on touching throttle in such cases.

Sl4yer 3rd Aug 2007 13:57


Originally Posted by GearDown&Locked
Working with those T/Ls...how difficult can it be?

Surely it would be more difficult to select just ONE lever and move it to idle?

Also heard in that video is the PNF calling the spoilers BEFORE reverse is selected.

SR71 3rd Aug 2007 14:06

Out of interest, what would the FADEC do when the AT disconnected if the No 2 thrust lever was retarded but only reached a position half-way between the climb detent and idle?

I ask, because very early on in my line training at the start of my flying career on the 737, I landed and retarded the thrust levers not quite to the idle stop.

I could subsequently not engage reverse thrust.

I mentioned the fact to the training Captain, who promptly took control and proceeded to try and rip the throttle quadrant out of the panel.

However, he experienced the same reluctance to go into reverse and we brought the aircraft to a halt without drama using the brakes.

On closer inspection, I saw the thrust levers were not quite at the idle stop.

The difference of a few mm made all the difference.

But PBL, you mention the position of the thrust lever is now in the public domain?

Does it correspond exactly to the climb detent?

I enjoy (if thats the right word) reading your comments BTW.

:)

borghha 3rd Aug 2007 14:20

Hi

I m surprised the translation into english of the CVR is quite poor and has created some confusion. The 'decelera' (decelerate- imperative mode) is followed by 'não da'. this refers neither to a subject (the PF) nor to an object (the TL) it means 'unable to' (execute what was asked, ie decelerate) It is very improbable that this frase refers to a problem with he TL according to me. (I m a linguist)

I can understand that at first one would be unaware of a forward thrust building up in the engine with the inop REV, since I suppose that the op REV produces the same loud noise in the cockpit as in the cabine, thereby masking the other engine spooling up. But when not decelerating with one REV on, why wouldn t it occur to one of the two pilots that something is pushing the plane forward? And that that could only be the other engine...

Perhaps the fact that the RETARD signal didn t stay on led both pilots to think that both engines were put at idle. Their minds must have been concentrating (too) hard on the engine with the op REV they would have to use as soon as possible given the situation at CGH.

If only TAM had implemented this extra warning....

Keep flying safely guys!

PPRuNeUser0172 3rd Aug 2007 14:26

may be way off piste here but on the vid link that GEARDOWNANDLOCKED posted, the spoiler lever does not appear to move on touchdown.............is that normal in the airbus??????

I was under the impression spoilers were armed during final approach and then deployed on landing, with the lever physically moving or is the airbus a lot cleverer than the boeing types??????

just curious

i-Robot 3rd Aug 2007 14:41

The speed brake/ground spoiler's lever is armed by the PNF physically, by pulling the lever out, so as to expose a white indicator/or marker on the handle itself. Upon touch down the spoilers are automatically deployed, and the only indication in the cockpit is on the lower crt (or Systems Display). The pilot can then observe whether the spoilers have deployed. If it hasn't, then one can physically move the lever, thus manually deploying spoilers.

But, to answer your question, once its armed and automatically activated, it doesn't move.

However, if the pilot advances the thrust levers (or just one thrust lever) into TOGA/GA mode, the spoilers automatically disarm and remain retracted, as the flight computers transition into the GA phase.

Very clever machine, if its utilised in the correct manner.

atakacs 3rd Aug 2007 14:54


The pilot can then observe whether the spoilers have deployed. If it hasn't, then one can physically move the lever, thus manually deploying spoilers.
uh ? I was under the impression that there was no way to deploy the ground spoiler's if the FBW systems doesn't get all the correct sensor readings (which was the case here) ?!

Can you confirm that you can always manually deploy the ground spoiler ?

Mad (Flt) Scientist 3rd Aug 2007 14:56


If it hasn't, then one can physically move the lever, thus manually deploying spoilers.
Are you sure? The A320 FCOM seems to suggest that speedbrake is inhibited in config FULL, which would imply that moving the lever won't cause anything to happen.

edit: beaten to it

Hand Solo 3rd Aug 2007 15:21

Latest hot poop from Airbus summarised:

Aicraft was stable and on correct profile.
TL1 was selected to idle but TL2 remained in clim detent.
After touchdown TL1 selected to REV and A/THR disconnects as per design.
TL2 remains in CLB and ENG2 EPR is fixed at value it was at the time of A/THR disconnection, approx 1.2 EPR (a typical approach setting).
Spoilers fail to deploy and autobrake not activated.
Manual braking commenced after 11 secs and aircraft departed the runwa at approx 100kts.

atakacs 3rd Aug 2007 15:55


TL2 remains in CLB and ENG2 EPR is fixed at value it was at the time of A/THR disconnection, approx 1.2 EPR (a typical approach setting).
Spoilers fail to deploy and autobrake not activated.
Just wondering - what's the biggest problem here ? Obviously one engine producing 1.2 EPR thrust is not good news but I would say that the real killer is the no spoiler / autobrake. Without them, even with the 2nd engine on idle, it is very likely that they would overshoot.
...and there was simply no way around it, even if they had a full understanding of what was going on (short of going around, but not recommended once T/R are deployed) :{
I am still convinced that the 320 systems can be improved - lets just start by making that dreaded Service Bulletin urgent and mandatory !
As an aside note: is there any material (here on elsewhere, haven't manage to google it) describing the design decision (and expected gain) of not having feedback built in the T/L mechanism ?

bubbers44 3rd Aug 2007 15:55

11 seconds to manual braking? How could that be?

DozyWannabe 3rd Aug 2007 16:12


atacaks:
As an aside note: is there any material (here on elsewhere, haven't manage to google it) describing the design decision (and expected gain) of not having feedback built in the T/L mechanism ?
Educated guesses here, but I'd imagine something like:

- Less weight
- FADEC does not require direct cable connection to the engine anyway
- Fewer moving parts to go wrong

for starters.

I read a while ago about a glitch in the FADEC software for the 777 that caused a reduction in thrust at takeoff. None of the articles I read mentioned whether the levers moved or not in that situation, but that the pilots initially saw it as a significant drop in N1.

In the case of this incident though, it would appear the FADEC was doing exactly as the TL positions requested.

Zeke 3rd Aug 2007 16:13


Originally Posted by SR71
Out of interest, what would the FADEC do when the AT disconnected if the No 2 thrust lever was retarded but only reached a position half-way between the climb detent and idle?

Spoilers would deploy and autobrake would work, the requirement is for both thrust levers at idle or one in reverse and the other idle or reverse or near idle (which is within 15 degrees or idle), the engine that is not at idle would still produce forward thrust, but would be closer to a level that you would use for taxi.

If you make no effort to reduce or increase both the thrust lever angles from that used for approach, nothing will happen. The aircraft is designed to be go minded, not stop minded, it assumes you want to do a touch and go or aborted landing.

ChristiaanJ 3rd Aug 2007 16:15


Originally Posted by "borghha
.... 'não da'. this refers neither to a subject (the PF) nor to an object (the TL) it means 'unable to' (execute what was asked, ie decelerate)...

What is 'não da' litterally?
Is "da" from "dar" = give?
If so, it could be somewhat like the French "ça ne donne rien" = it doesn't do anything, we're not getting any [deceleration].
Since it now has been mentioned repeatedly with various translations, maybe you or one of our Portuguese members can clear this up?
CJ

hetfield 3rd Aug 2007 16:16

@i-Robot
 

The pilot can then observe whether the spoilers have deployed. If it hasn't, then one can physically move the lever, thus manually deploying spoilers.

:ooh: How come?

Grunf 3rd Aug 2007 16:19

Answer to Flyingnewbie10's post #1015
 



First off manufacturers do not make regulatory rules regarding the (re)fitting of parts or procedures. They are recommendations only and are submitted to the regulatory authorities for their juristiction.
So why does AirBus label some of them as "mandatory" and others not.
Could you please explain ?
If communication from OEM is coming as a result of an AD (Airworthiness Directive) then it is mandatory. If it is a SB (Service Bulletin) then it is not mandatory.

Recommendations are always optional. Only ADs are mandatory, with the appropriate time frame for application.

Regards,

atakacs 3rd Aug 2007 16:23


In the case of this incident though, it would appear the FADEC was doing exactly as the TL positions requested.
no debate here... just that it might be useful to have a physical feedback between the two IMHO. Is this "decoupled" T/L philosophy similar on the whole Airbus fleet, from the A300 to the 380 ?

DozyWannabe 3rd Aug 2007 16:30

I *believe* it's only from the A320 series onwards (A32/3/4/80)). The A300 series is an older, more conventional design (albeit with a very advanced AP for its age IIRC).

As with most things, I think there are benefits and drawbacks to both philosophies, but both are more than adequate for day to day operation. The argument for the traditional system here seems to be more geared towards a side-effect of that system in that you won't physically be able to put the levers in reverse unless they're both or all at idle, as opposed to the levers tracking what the A/THR is doing.

The A320 system is more like the speed telegraph system in the days of the ocean liner, requesting a speed from the engines (or A/THR) rather than directly setting it. It's a perfectly valid and safe system IMO, as long as you understand it.

hetfield 3rd Aug 2007 16:34

@atakacs
 
A300 has a very similar TL system like B737 (which I haven't flown, but was told so). Means moving TL, thrust rating panel, no FADEC.

Some people say A300 is the best BOEING ever build by AIRBUS.

regards

ChristiaanJ 3rd Aug 2007 16:39


The A300 series is an older, more conventional design (albeit with a very advanced AP for its age).
No wonder.... the AP traces its ancestry back to Concorde.


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