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

wileydog3 20th Jul 2007 12:37

+++++One of the insidious things about the non-moving thrust levers and managed speed is that the engine instrument scan becomes degraded.++++

The non-moving throttles become a non-issue as one adapts to the Bus. Yes, there is no tactile feedback as with moving throttles but remember autothrottles, if engaged, will move even if the engine is shut down so it can give false information on what the engine is doing.

After Boeings, Airbus, Fokkers, MDs and a slew of gen-av machines, the rule is play to the strengths and respect the weaknesses regardless... and if you up to your *ss in alligators it is difficult to focus on the tasks at hand.. moving or non-moving throttles.

wileydog3 20th Jul 2007 13:01

++++Maybe constant repetition, despite the snow on the ground, lulled those pilots into believing that with operative anti-skid, autospoilers and thrust reversers, the landing should have been no problem?+++

No doubt that over time, one accumulates a personal 'database' of events. In any endeavor, the 'been there, done that' attitude can develop due to repetition. Same airport, same approach, same winds, same.. same.. same.

A few years ago a SW Capt Steve Swauger wrote and presented a paper on how experienced pilots can respond like novices when presented with a situation well outside the routine. I can not find it on the net currently but it is an EXCELLENT discussion worth reading and for any pilot, thinking about its application. One major point was that IF you have to be constantly revising your solution to the problem, you probably are working with a failed solution and it is time to abandon the effort and begin again.

A second point is that we, as aviators, quickly respond to the blinking red light and the honking horn but we can miss the cues when things are failing but doing so only gradually. And when you add reinforcement from other sources such as no one missing the approach, no one going around, no one having problems clearing the runway after landing, no reports of braking problems, one would have to be somewhat psychic to conclude that the day is anything other than just another day at the office.

TopBunk 20th Jul 2007 13:06

J.O.


The A320 will activate the approach automatically at the DECELERATE pseudo waypoint. So, even if they forgot to manually activate the approach phase, it would have been activated automatically by the time they reached the FAF.
Are you sure? I know that is is true if you do an ILS, but what about a NPA? I am probably wrong, but I thought a NPA was different. I haven't flown the type for 18 months, but it was with this in mind that I speculated as to how an undesired increase in speed could occur.

Looking at my old manuals, it says 'app phase will activate automatically when flying over the decel pseudo waypoint with NAV, APPR NAV, LOC* or LOCmode engaged. You will activate manually if in HDG or TRK mode.

TopBunk 20th Jul 2007 13:16


The non-moving throttles become a non-issue as one adapts to the Bus. Yes, there is no tactile feedback as with moving throttles
WD3

I don't disagree (3000 hrs A320 family, 9000 hrs Boeing) ...BUT ... modern engines are much quiet(er) than older engines such as JT8D's. Ignoring for the moment the lack of pitch change with power on the FBW A320's, the glimpsing in your peripheral vision of thrust lever movement can be an early attention grabber and alert you to look at EPR's/N1's to see what is happening.

For someone new on type, the first thing you can be aware of is when you get a kick in the back as the beast accelerates like a scalded cat and you by then have gained 25kts or so. You are then in a recovery situation which takes some rapid actions or else a go around.

I have been caught (as I guess have most Airbus pilots) by this on occasion, typically when on a NPA using selected speed of say 160kts to 4nm, then changing to managed speed.

Now I am not suggesting that this happened in this instance, but it is one mechanism that could account for any excess speed.

As I said before, I still would put at the top of my probable causes list the slippery runway surface.

NigelOnDraft 20th Jul 2007 13:18

TopBunk/J.O. It is fairly irrelevant what the books say about when the Approach Activates itself - you are all better men than me if you have never had that "****" feeling as you "Manage" the speed and it goes to Clb power on shortish finals :eek:

wileydog3 20th Jul 2007 13:23


I don't disagree (3000 hrs A320 family, 9000 hrs Boeing) ...BUT ... modern engines are much quiet(er) than older engines such as JT8D's. Ignoring for the moment the lack of pitch change with power on the FBW A320's, the glimpsing in your peripheral vision of thrust lever movement can be an early attention grabber and alert you to look at EPR's/N1's to see what is happening.
My first time on an MD-80 after years on the Boeings was, "How does this thing move without the engines running."

I enjoyed the 'bus and agree you had to pay attention to what it was doing but I thought that about the Lear 23 the first time I flew it.

theamrad 20th Jul 2007 13:27

Bomarc – about the spoilers – if you watch the last few seconds of video a few times, you might notice the dark area over the wing – To me it looks like they were up at that late point. If so, that would probably finish the attempted GA idea.


Wileydog3 -

A second point is that we, as aviators, quickly respond to the blinking red light and the honking horn but we can miss the cues when things are failing but doing so only gradually. And when you add reinforcement from other sources such as no one missing the approach, no one going around, no one having problems clearing the runway after landing, no reports of braking problems, one would have to be somewhat psychic to conclude that the day is anything other than just another day at the office.

If I remember correctly, I think this was one of the features in the Qantas overrun at Bangkok. I think mis-cued comms on the tower frequency prevented the accident aircraft from hearing that a second company a/c ahead had decided to go missed due quickly deteriorating conditions on late finals – and therefore, had no reason to believe conditions were worse than reported earlier. They were ‘denied’ an important cue which may have been the alert needed to avoid trouble. Although, like in so many accidents there’s a chain of events – it only takes one link being broken, or one alert, to avert potential disaster.

I haven’t seen the work you refer to – but have seen the effect of ‘conditioning’ referred to many times before.

bomarc 20th Jul 2007 13:48

shouldn't the spoilers retract automatically if a go around was attempted?

wingview 20th Jul 2007 13:51


Bomarc – about the spoilers – if you watch the last few seconds of video a few times, you might notice the dark area over the wing – To me it looks like they were up at that late point. If so, that would probably finish the attempted GA idea
Do you remember the 757 at Cali? They also forgot them. But it's all speculations right now.

TopBunk 20th Jul 2007 14:02

NoD, you said:

you are all better men than me if you have never had that "****" feeling as you "Manage" the speed and it goes to Clb power on shortish finals
and I had said:

I have been caught (as I guess have most Airbus pilots) by this on occasion
Absolutely - when experienced on type, you immediately know what has happened, in the early learning days you "****" yourself.:uhoh:

theamrad 20th Jul 2007 14:19


shouldn't the spoilers retract automatically if a go around was attempted?

Can’t speak for AB with 100% certainty - I BELIEVE is the same as Boeing – autospoiler will retract for advancing thrust levers. If indeed the same – that’s why it would indicate no GA attempt.


Do you remember the 757 at Cali

Performance calculations seemed to suggest that retracting spoilers during the escape manoeuvre MAY have allowed that 757 to clear the terrain – but I don’t think it was proven to be an absolute certainty?? My memory is a bit vague on the point. More to the point – the question of spoiler retraction SHOULD be different for Boeing in the LANDING case: whether applied automatically or manually.

Maybe someone typed on A320 could tell us – will spoiler retract automatically if TO thrust selected for GA – whether auto or manual deploy?

Johnbr 20th Jul 2007 14:29

Yes, the spoilers will retract upon selection of toga.I have flown the buses (319/320/330) for 7 years and I cannot see how in hell the plane itself had a part in this accident.Reverser inop will heve almost no effect on stopping performance,as it is on any other commercial jet I have flown(737/200,300 and MD11).

alf5071h 20th Jul 2007 14:33

How experienced pilots can respond like novices.
 
Wiley I think that the article you refer to (post #258) is “How good pilots make bad decisions: a model for understanding and teaching failure management to pilots“; this was last found at http://www.spatiald.wpafb.af.mil/2003/ISAP_162.pdf, but this link appears to have closed.
However, just for you it is here; see HOW_GOOD_PILOTS_MAKE_BAD_DECISIONS_ISAP_162.pdf. Also see ‘Errors_in_aviation_decision_making_Orasanu.pdf’
Aspects of these articles have been incorporated in the presentation Managing the Threats and Errors during Approach and Landing - How to avoid a runway overrun (slide 17). Although this and the articles above were written with pilots in mind, the issues discussed apply equally to all levels of management. They, the decision makers, need to look out of the window more often, check the wind and the rain, the availability and state of the overrun area, the runway surface. They have to engage with the operation – note how far down the runway the aircraft are before they are really under control in the prevailing conditions.
Afterthought: pilots also have to answer the question “how far down the runway was the aircraft before it was really under control/stopping” – how many honest views, (self reflection) would result in an answer that gave a position which was consistent with landing within the factored distances? And where is that position on each runway?

aluminum overcast 20th Jul 2007 14:34

Flash Hypothesis
 

Quote:
Flash on the Video
--------------------------------------------------------------------------------
Has anyone commented on the flash visible from the left side of the aircraft on the video just before it disappears from view?
One hypothesis: Reverse thrust was selected on Eng 1 (eng 2 rev thrust was deactivated). Pilots realize they will not be able to stop the aircraft and, contrary to the recommendations of the FCOM (Flight Crew Operating Manual) to execute a full stop after reverse thrust is selected, initiate a go-around by pushing the trust levers to TOGA. An engine going from full rev to full forward thrust could possibly suffer a compressor stall while the reverser doors are closing, causing the flash we see in the video.

Of course, they may have considered it was safer to try to get airborne again...

Raggyman 20th Jul 2007 14:38

Firstly wanted to say, how sad anything like this is, and how sad it is that you can't turn back time.

This is not aim at any speculation about this particular crash, but it is something that I don't know the answer to, and hoping that someone might know the answer.

Are there regulations in place that define the minium tread on aircraft tyres? I say this, I know how difficult it is to control a car that has very little tread, let alone an aircraft.

hetfield 20th Jul 2007 14:48

@Raggyman
 
Are there regulations in place that define the minium tread on aircraft tyres? I say this, I know how difficult it is to control a car that has very little tread, let alone an aircraft.

No, cause tread wouldn't help. Aeroplanes are touching down with more than 250 km/h. This means you will have aquaplaning anyway.

Raggyman 20th Jul 2007 14:59

@Raggyman

--------------------------------------------------------------------------------

Are there regulations in place that define the minium tread on aircraft tyres? I say this, I know how difficult it is to control a car that has very little tread, let alone an aircraft.

No, cause tread wouldn't help. Aeroplanes are touching down with more than 250 km/h. This means you will have aquaplaning anyway.


Ah ok, interesting.. but would it not matter latter on down the track when your speed had decreased? Or do aircraft tyres pretty much aquaplane anyhow no matter how fast you are going?

BOAC 20th Jul 2007 15:02

Johnbr -

Reverser inop will heve almost no effect on stopping performance,
- I'd be intrigued to know how you would propose to stop on a very slippery runway?

hetfield 20th Jul 2007 15:13

@Raggyman
 
For example, aquaplaning speed for 737 NG is between 93-123 kts on the Main Gear. Once aquaplaning has started, it will continue to a much lower speed.

Rippa 20th Jul 2007 15:21

More speculation, today on the local TV news (not a very secure source, but...)

- 17:03 LT - GOL B 737-800 lands at CGH and reports "slippery runway"
- 17:04 LT - INFRAERO, local airport manager, closes the airport for landing and takeoff ops. INFRAERO engineers measures the standing water: 0,6 mm.
- 17:30 LT - Airport returns to normal ops.
- 18:50 LT - PR-MBK lands at CGH.

Remark: Between 1730 and 1850, 40 aircrafts (majority of them were airliners - B 737 and A319/320) landed at CGH and no problem was reported.


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