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TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 5:32 am

Continuing discussion from:
TAM Plane Crashed In CGH (by LipeGIG Jul 18 2007 in Civil Aviation)
TAM Plane Crashed In CGH Part 2 (by BNE Jul 18 2007 in Civil Aviation)
TAM Plane Crashed In CGH Part 3 (by PanAm_DC10 Jul 19 2007 in Civil Aviation)
TAM Plane Crashed In CGH Part 4 (by PanAm_DC10 Jul 20 2007 in Civil Aviation)
TAM Plane Crashed @ CGH Pt. 5. (by Srbmod Jul 25 2007 in Civil Aviation)
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PPVRA
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 5:42 am

I'm gonna re-post my question from Part5:

Quote:

18:48:23.0
FWC retard.
18:48:24.5
CAM [sound of thrust lever movement]
18:48:24.9
CAM [sound of increasing engine noise]
18:48:25.5
GPWS retard
18:48:26.3
CAM [sound similar to touchdown]
18:48:26.7
HOT-2 reverse number one only.
18:48:29.5
HOT-2 spoliers nothing.

If that was indeed the last "retard" alarm, why was it the last one? Apparently they didn't have the thrust levers all the way in the proper position, for some reason, but the FWC should have continued with the warning until they solved it, no?
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dellatorre
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 7:05 am

Here are the latest developments in the investigation:
http://www.cnn.com/2007/WORLD/americ...1/brazil.crash.cause.ap/index.html
 
DeC
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 8:43 am

From: http://www.cnn.com/2007/WORLD/americ...1/brazil.crash.cause.ap/index.html

"The recording ends with screams and a woman's voice, followed by an explosion."

Any idea who that woman might me?
DEC
 
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zeke
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 8:52 am

Quoting Katekebo]Which actually is a manageable situation. You CAN still abor the landing right at touchdonw, and take off on one engine at TOGA, and the other one in idle, with no spoliers, starting from a normal approach speed, within a normal runway length. But you CAN"T stop on the runway without spolier, brakes and only one reverser. I'm sure Zeke can confirm that.[/quote]

Nothing on the A320 stops you from doing a touch and go, as soon as the nose wheel hits the runways, the stab trim if required will automatically go back to the takeoff range, when doing circuits we would make sure no reverse or spoilers are activated, retract the flaps to CONF 2, place the thrust levers to get above 50% N1, then TOGA, rotation occurs shortly there after.

As for doing one with one engine at IDLE, you would need to be above Vmcg/Vmca, Vmcg at 2000' altitude would be 107.5 kt for CONF 2, and Vmca 110.5 kt, you would also need to retract some flap to get ri

You can stop on a runway "without spolier, brakes and only one reverser", just needs to be a longer runway.

Quoting Mandala499:
I knew I missed something from reading those damn FCOMs... which are old... have they made the T/R reverse signal through the SEC above the FADEC receiving the T/R signal?

Would be covered in the power plant section (70), not flight controls.

[quote=PPVRA
(Reply 1):
If that was indeed the last "retard" alarm, why was it the last one? Apparently they didn't have the thrust levers all the way in the proper position, for some reason, but the FWC should have continued with the warning until they solved it, no?

Not if reverse has been selected.

Quoting Dellatorre (Reply 2):
Here are the latest developments in the investigation:

CNN would be the last place I would go to for accurate aviation news.

Quoting DeC (Reply 3):

Any idea who that woman might me?

Had a number of TAM employees on the aircraft, maybe one of them was in the jump seat.
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
DeC
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 8:58 am

Quoting Zeke (Reply 4):
Had a number of TAM employees on the aircraft, maybe one of them was in the jump seat.

Yeah, forgot about that. Thanks
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NAV20
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 10:38 am

Quoting PPVRA (Reply 1):
If that was indeed the last "retard" alarm, why was it the last one? Apparently they didn't have the thrust levers all the way in the proper position, for some reason, but the FWC should have continued with the warning until they solved it, no?

PPVRA, covered on the previous thread. The 'retard' call cuts off once the aircraft is down, whether or not the throttles are at idle. This feature was criticised by the Taiwan Air Safety Council after one of three previous 'one reverse thruster inop./one throttle not set to idle' A320 accidents:-

"1. After touchdown, when the thrust lever 2 was not pulled back to Idle position and the Retard warning sounds have ceased, there were no other ways to remind pilots to pull back the thrust lever."

Airbus responded at that time (2004) as follows:-

"Airbus has developed a specific warning when one throttle is set to reverse while the other is above idle. This warning generates an ECAM warning "ENG x THR LEVER ABV IDLE", a continuous repetitive chime (CRC), and lights the red master warning light. This new warning is implemented in the FWC standard "H2F3".

"A Service bulletin will be issued very soon on this subject."


As far as I've been able to establish, the revised warning system (consisting of a message on the 'Electronic Centralised Aircraft Monitoring' screen) is being incorporated in new construction. The same thing can be fitted as a modification to existing aircraft, but (again as far as I know) it is classified as 'desirable' rather than essential (that is, it is not the subject of a compulsory Airworthiness Directive).

Full report here:-

http://www.asc.gov.tw/acd_files/189-c1contupload.pdf

As you'll see, the two events were very similar (as were the Bacolod and Phoenix incidents also detailed on the previous thread).

"When the aircraft was below 20 ft RA and Retard warnings were sounded, the pilot flying didn't pull thrust lever 2 to Idle detent which caused the ground spoilers were not deployed after touchdown though they were at Armed position, therefore the auto braking system was not triggered. Moreover, when the auto thrust was changed to manual operation mode automatically after touchdown, the thrust lever 2 was remained at 22.5 degrees which caused the Engine 2 still had an larger thrust output (EPR1.08) than idle position's. Thereupon, the aircraft was not able to complete deceleration within the residual length of the runway, and deviated from the runway before came to a full stop, even though the manual braking was actuated by the pilot 13 seconds after touchdown."
"Once you have flown, you will walk the earth with your eyes turned skywards.." - Leonardo da Vinci
 
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 10:45 am

Quoting Zeke (Reply 4):
Quoting Dellatorre (Reply 2):Here are the latest developments in the investigation:
CNN would be the last place I would go to for accurate aviation news.

Really? You'd go to Fox news before CNN?  Wink
"Suppose you were an idiot. And suppose you were a member of Congress. But I repeat myself." Mark Twain, a Biography
 
PPVRA
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 10:58 am

Quoting Zeke (Reply 4):



Quoting NAV20 (Reply 6):

Oh ok, thanks for the info. Interesting post, NAV20.
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zeke
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 11:16 am

Quoting NAV20 (Reply 6):

As far as I've been able to establish, the revised warning system (consisting of a message on the 'Electronic Centralised Aircraft Monitoring' screen) is being incorporated in new construction. The same thing can be fitted as a modification to existing aircraft, but (again as far as I know) it is classified as 'desirable' rather than essential (that is, it is not the subject of a compulsory Airworthiness Directive).

Nav,

AFAIK that software version is not standard at all, as for only being "classified as 'desirable' rather than essential", you dont get any prompt on a Boeing, Douglas, McD, Fokker, BAe at all, if it was essential, it would be fitted to all aircraft types.

Even on a light twin, you can land with one throttle at idle, one left at approach setting, you will get no warning, like on an Airbus, it is normal pilot technique to bring back all thrust levers/throttles to idle on landing.

The split between the two thrust levers if one was in CLB and one at MAX REV is significant, over 40 degrees of arc difference, or about 15-20 cm.
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NAV20
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 12:13 pm

Agree, Zeke, not making a big thing out of 'desirable' only; after all, up to that time, there had only been a few relatively-minor incidents. Surprised, though, that it's still not standard,seems to be a relatively-simple addition by aircraft software standards?

Quoting Zeke (Reply 9):
it is normal pilot technique to bring back all thrust levers/throttles to idle on landing.

Definitely, it's one of the first things you learn - along with not forgetting to lower the gear!   As you know, I never got far beyond the 'first things.' Both of us have said in past threads that we can't understand how such experienced pilots could have done such a thing.

That sparks a bit of 'lateral thinking.' There have now been four A320 accidents in which vastly-experienced pro pilots were held either to have forgotten to retard one lever, or to have retarded it and later pushed it forward. In the Taipei and Bacolod incidents, the accusation was that the pilots had put the lever to 'CLIMB'. In the Phoenix case the pilot was actually accused of having pushed it all the way to 'TOGA' (i.e. max. takeoff power).

If you look out the NTSB report on Phoenix you'll find that the pilot denied doing this. But the Flight Data Recorder said that he had, and the NTSB chose to believe the FDR - and FDR evidence was considered conclusive at Taipei and Bacolod as well.

I find that I keep recalling the 'common factor' in all four accidents - that all four aeroplanes had one reverse thruster 'inoperative,' meaning that the maintenance people had disconnected/locked it so that it could not operate.

Only thinking aloud here - but is there ANY possibility that the procedure for 'locking out' reverse thrust on one side could affect the software so that lever positions/power settings etc. could be misinterpreted by both the engine controls and the FDR?

[Edited 2007-08-03 05:21:42]
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Pu752
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 1:47 pm

Quoting NAV20 (Reply 10):
Only thinking aloud here - but is there ANY possibility that the procedure for 'locking out' reverse thrust on one side could affect the software so that lever positions/power settings etc. could be misinterpreted by both the engine controls and the FDR?

As a fellow pilot I have to say no, but captains always make the right decision on extreme situation (thats why the earned that position) , at least as a co-pilot no matter if my captain made the wrong decision at that time, I'll fully support him.

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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 3:24 pm

That Phoenix NTSB Report bears looking at. By a rich irony, the 'drill' at that time (2002), as clearly stated by the NTSB, was only to apply reverse thrust on the engine with a working reverser, and leave the other one at 'Idle'; as the NTSB makes clear (bringing them both back to 'reverse' was one of the things they appear to have blamed the pilot for).

"According to the MEL, when a thrust reverser is deactivated "it is recommended not to select reverse thrust on affected engine at landing."

Airbus have since changed that procedure to putting both levers into 'reverse,' even if one of the reversers is inop. - anyone know when - and why - they changed it?

The rest of the Report says, in part (excerpts only to keep this post short, full Report available here, click on 'Full Narrative Available' at the bottom):-

http://www.ntsb.gov/ntsb/brief.asp?ev_id=20020913X01603&key=1

"Probable Cause:- The captain's failure to maintain directional control and his inadvertent application of asymmetrical engine thrust while attempting to move the #1 thrust lever out of reverse. A factor in the accident was the crew's inadequate coordination and crew resource management.

"The captain, age 59, held an airline transport pilot certificate, with an airplane single and multiengine land and rotorcraft helicopter ratings. He held type ratings in the Airbus A320 and the DHC-8. He possessed a first-class aviation medical certificate with the limitation that he must have available glasses for near vision.

"A review of the captain's FAA records indicated that he had no history of prior accidents, incidents, or enforcement actions. The captain's total flight time was reported at 19,500 hours, of which 7,000 hours were as captain flying an A320.

"The accident airplane's DFDR data indicated that about 4 seconds before the nose landing gear touched down, both thrust levers were brought to the idle position (0 degrees thrust lever angle (TLA)). As the nose gear touched down, both engine's thrust levers were brought to the full reverse position (-25 degrees TLA). During the next 8 seconds, the #1 thrust lever moved from the full reverse position to idle, then to the cruise position (+25 degrees TLA), and ultimately to the Take-Off/Go Around (TOGA) position, where it remained for 11 seconds before returning to the idle position. During this same period, the #2 thrust reverser remained at full reverse for 18 seconds, was moved to near the cruise position for about 2 seconds, and then returned to the idle position, concurrently with the #1 thrust lever. During the 11 seconds when the #1 engine was at TOGA thrust and the #2 engine was at full reverse, a right yawing motion occurred.

"In the captain's written statement he reported, in part, that after retarding both thrust levers to the idle position, he engaged the #2 (right side) thrust reverser. Shortly thereafter, the airplane started slowly diverging to the right. The captain reported that he reached down to ensure that the #1 (left side) thrust lever was in idle, and he reduced thrust on #2 while feeding in left rudder steering. The airplane did not respond to the steering input, so he added more pressure to the left brake, which did not correct the airplane's course. The airplane exited off the right side of the runway, and the nose wheel dropped into a ditch.

"The first officer reported that, following touchdown, he noticed an increase in engine sound as the captain selected reverse thrust. He stated that a Master Caution Light was illuminated and a single chime was heard for a #1 thrust reverser fault. He did not consider this significant because the #1 thrust reverser had been deactivated per the MEL. He indicated that the airplane began to veer right, and the captain brought the engines out of reverse thrust. The first officer additionally reported that during this time his attention was focused outside the airplane, and that at this point he thought that they would stay on the runway, with drift being stopped or possibly a correction to the left already begun. Instead the airplane veered farther right, and he could see the airplane was going to depart the runway.The first officer stated he instinctively applied maximum brakes with both feet without a request from the captain. The first officer stated that he received no instructions from the captain during the accident sequence."
"Once you have flown, you will walk the earth with your eyes turned skywards.." - Leonardo da Vinci
 
mandala499
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 4:13 pm

NAV,
I really do not understand why do we need to add a warning on the fact that 1 in reverse and 1 in positive when it comes to the engine instrumentation. The PF should also look at the engine indications upon reverser deployment or have the PNF do that for him. This is also to prevent the engine from becoming damaged through excessive reverser application at low speed (oh yeah, those compressor stalls are nicely loud)... So, the cases where 1 throttle is left at CLB on the 320 is NOT only lack of adherence to the procedures on flare, but also on the landing roll. It can therefore be attributed to CRM failure, and not an aircraft failure. The common factor in the 4 accidents are lack of adherence and possibbly a common passive failure in CRM during a critical phase.

(Interesting that after I wrote the above, I read Nav's reply 12 and see the NTSB stated a similar thing.)

Things such as the "Ground override button" or even this:

Quoting NAV20 (Reply 6):
Airbus responded at that time (2004) as follows:-

"Airbus has developed a specific warning when one throttle is set to reverse while the other is above idle. This warning generates an ECAM warning "ENG x THR LEVER ABV IDLE", a continuous repetitive chime (CRC), and lights the red master warning light. This new warning is implemented in the FWC standard "H2F3".

may all look nice... but even if its developed, it must be assessed and its benefits and risks analyzed, prior it being put into service. It's part of the systems engineering standards Boeing and Airbus strictly adhere to. Even if the warning Airbus developed for H2F3 ended up being implemented, they could take it out again on H2F4... *grin*

These things need to be tested in its practicality, tested for situations it is designed for, and tested for situations it is NOT designed for, and tested for nuisance warning generation and diagnosis. Then it would have to go through the human interface test and see whether it is useful or not... see whether it goes along with the process flow ingrained into a pilot's head from prior training and general airmanship, and see whether a feature to be introduced is counter intuitive.

The above paragaph is where Airbus as so far pushed the limits on crew adaptability, and has so far succeeded... and testimonies from crew who converted to the Bus has said that the Bus does emphasize on certain things that may initially appear to be counter-intuitive in their training to ensure that the crew understand the system.

As to pilots with high hours... let me say that (and pilots may be insulted by this and if so, I apologise beforehand), it ONLY means that they've flown a lot... no more, no less. Total number of hours by a pilot indicates a potential quality and experience but does not in any way imply quality. I know one MD11 pilot with over 20,000hrs moving to the Airbus and then move back to the MD11 because he was unable to adapt... I know pilots with 20,000hrs miss out checklists and at one stage it almost ended with a plunge into a city suburbs, and was in an aircraft with a pair of pilots each with 20,000hrs (and one was >10,000hrs on type) deliberately not adhere to aircraft procedures. Or that one who gave me a blank face when asked what a 4th segment climb is. Never assume that a pilot with >20,000hrs would know what he's doing all the time... coz when he doesn't know, sometimes he can be more dangerous than the guy with <10,000hrs.

As others have said, don't just take snippets... see the whole picture and understand why the snippets are there.

Mandala499
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iwok
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 5:40 pm

Quoting Mandala499 (Reply 13):
I really do not understand why do we need to add a warning on the fact that 1 in reverse and 1 in positive when it comes to the engine instrumentation. The PF should also look at the engine indications upon reverser deployment or have the PNF do that for him. This is also to prevent the engine from becoming damaged through excessive reverser application at low speed (oh yeah, those compressor stalls are nicely loud)... So, the cases where 1 throttle is left at CLB on the 320 is NOT only lack of adherence to the procedures on flare, but also on the landing roll. It can therefore be attributed to CRM failure, and not an aircraft failure. The common factor in the 4 accidents are lack of adherence and possibbly a common passive failure in CRM during a critical phase.

After having read through all these posts, I can't for the life of me figure out why the use of TR with one out is allowed. Especially on a light twin with wing mounted engines. How much is one TR going to save you anyway?

Also, during a complex landing with a heavy bird, bad weather and a wet and slick runway I think it might be better if the pilots just focused on making a nice firm landing to get the squat sensors engaged, make sure both throttles are at idle and stomp on the auto brakes. In doing so you get all the things you need for a good stop, and most importantly the spoilers will deploy.

iwok
 
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zeke
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 6:48 pm

Quoting Iwok (Reply 14):
Also, during a complex landing with a heavy bird, bad weather and a wet and slick runway I think it might be better if the pilots just focused on making a nice firm landing to get the squat sensors engaged, make sure both throttles are at idle and stomp on the auto brakes. In doing so you get all the things you need for a good stop, and most importantly the spoilers will deploy.

Spoken like a true armchair airline pilot......  banghead 
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Summa767
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 7:30 pm

Quoting Mandala499 (Reply 13):
I really do not understand why do we need to add a warning on the fact that 1 in reverse and 1 in positive when it comes to the engine instrumentation.

Look, the fact that there were precedents before TAM 3054, seems to me that adding such a warning would not be redundant, especially when it should be very simple to implement. It maybe basic bad airmanship to leave a TL on positive, -but it has happened, and not just once- , and given the serious consequences of such a disparity, exacerbated by the system overriding all but the wheel braking, seems to me to justify it.

Having said that, this TAM accident will ensure that the revised correct procedures for landing with one inoperative thrust reverser will be emphasised to such an extent that it will leave no A320 pilot with a doubt as to move the levers together even if one TR is inoperative.

[Edited 2007-08-03 12:31:33]
 
NAV20
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 9:48 pm

Quoting Mandala499 (Reply 13):
really do not understand why do we need to add a warning on the fact that 1 in reverse and 1 in positive when it comes to the engine instrumentation.

Mandala, the short answer is that (from the transcript) the pilots appear to have been utterly confused by what was happening - or rather NOT happening. And, as a result, upwards of 200 people died. Any further occurrences of this kind must be avoided at all costs. Yet more cryptic amendments to the operating manuals are unlikely to be enough.

As I said earlier, the simplest solution would probably be to remove the 'both engines to idle' requirement from the criteria for the deployment of autobrakes and ground spoilers. I still have no idea why it was ever included in those criteria anyway.
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Jan Mogren
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 9:53 pm

Quoting Iwok (Reply 14):
stomp on the auto brakes

Right...
What do you mean exactly?

/JM
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 10:15 pm

Quoting Iwok (Reply 14):
After having read through all these posts, I can't for the life of me figure out why the use of TR with one out is allowed. Especially on a light twin with wing mounted engines. How much is one TR going to save you anyway?

Also, during a complex landing with a heavy bird, bad weather and a wet and slick runway I think it might be better if the pilots just focused on making a nice firm landing to get the squat sensors engaged, make sure both throttles are at idle and stomp on the auto brakes. In doing so you get all the things you need for a good stop, and most importantly the spoilers will deploy.

You might think so, but the procedure was hardly plucked out of thin air.

Quoting NAV20 (Reply 17):
Mandala, the short answer is that (from the transcript) the pilots appear to have been utterly confused by what was happening - or rather NOT happening. And, as a result, upwards of 200 people died. Any further occurrences of this kind must be avoided at all costs. Yet more cryptic amendments to the operating manuals are unlikely to be enough.

I agree that there should be no further occurrences. But if it turns out training was deficient or they were simply screwing it up by the numbers, would a change to the instrumentation have saved them?

Quoting NAV20 (Reply 17):
As I said earlier, the simplest solution would probably be to remove the 'both engines to idle' requirement from the criteria for the deployment of autobrakes and ground spoilers. I still have no idea why it was ever included in those criteria anyway.

Because if both engines are not at idle the pilots may be considering a go around. In this case the last thing you want is autobrakes and spoilers.


Pulling the thrust levers back to the idle stops is hardly rocket science by the way. There should be no problem getting a positive reading from the aircraft on this one. If the pilots want to stop, they will pull the thrust levers back to the stops and autobrakes+spoilers will deploy. If they do not want to stop, they do not pull the thrust levers back. What's so hard about it?
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
mandala499
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 11:04 pm

Quoting Iwok (Reply 14):
After having read through all these posts, I can't for the life of me figure out why the use of TR with one out is allowed. Especially on a light twin with wing mounted engines. How much is one TR going to save you anyway?

I'm not sure what you're saying here, on the first sentence you're saying that a single T/R shouldn't be allowed? And the last sentence is you don't see how much the reverser is going to save you?

T/R is an ADDITIONAL deceleration item, ie: a BONUS item. You land, bring the engines to idle, with the primary deceleration devices out (ground spoilers and wheel brakes) operating, you should be able to stop... that is correct... don't use the reverser(s) in your landing calculations. However, you know why the reversers are there... it's to assist in the deceleration... ie: reduce the load on the brakes you require... and, when things go wrong, bung them on and get it to assist slowing the aircraft down... Even with a single T/R, that single reverser may be the difference between 1 landing gear on the mud, or none... BUT, careless use will probably result in 1 landing gear or more having a quick or one way trip to the grass. Even if you have ALL T/Rs operating, landing on a wet runway in high cross winds can result in you going to the grass too if you're not careful.

Quoting Iwok (Reply 14):
Also, during a complex landing with a heavy bird, bad weather and a wet and slick runway I think it might be better if the pilots just focused on making a nice firm landing to get the squat sensors engaged, make sure both throttles are at idle and stomp on the auto brakes. In doing so you get all the things you need for a good stop, and most importantly the spoilers will deploy.

They already do! Except, they do not stomp on the autobrakes. Training for landing (especially on wet runways) involves ensuring you get the plane firmly on the runway, throttles on idle. But you do not STOMP on the autobrakes, doing so will disengage the autobrakes...

Quoting Summa767 (Reply 16):
Look, the fact that there were precedents before TAM 3054, seems to me that adding such a warning would not be redundant, especially when it should be very simple to implement. It maybe basic bad airmanship to leave a TL on positive, -but it has happened, and not just once- , and given the serious consequences of such a disparity, exacerbated by the system overriding all but the wheel braking, seems to me to justify it.

Sure, but how many single reverser landings on wet runways (and night time too) has happened without a glitch. How about trying to sort out flap assymetry overrun landings, or unstable approaches leading to overruns... what's been happening to those cases? (there's been more than 1 case on this) Nothing, just more emphasis on the training to make sure the crew does the right thing. How about the Kegworth case where the crew misread the EIS and shut down the wrong engine, how many wrong shutdowns have happened since? We only heard about that one because it crashed. But what was the outcome? Most airlines decided that better training was the way! Until someone comes up with the statistics saying that the occurences of "single T/R landings leading to thrust lever asymmetry causing overruns" out of the total number of landings on a particular type and also out of landings on single T/R, showing that it is statistically significant, the argument is moot... although it would be a nice feature to have. There's a difference in trying to mitigate a risk due to the aircraft's system and a risk of crew not adhering to the procedures. For the latter, unless it is statistically significant, the solution will be as what you said later on...

Quoting Summa767 (Reply 16):
Having said that, this TAM accident will ensure that the revised correct procedures for landing with one inoperative thrust reverser will be emphasised to such an extent that it will leave no A320 pilot with a doubt as to move the levers together even if one TR is inoperative.

That is the solution.

Quoting NAV20 (Reply 17):
Mandala, the short answer is that (from the transcript) the pilots appear to have been utterly confused by what was happening - or rather NOT happening. And, as a result, upwards of 200 people died. Any further occurrences of this kind must be avoided at all costs. Yet more cryptic amendments to the operating manuals are unlikely to be enough.

As I said earlier, the simplest solution would probably be to remove the 'both engines to idle' requirement from the criteria for the deployment of autobrakes and ground spoilers. I still have no idea why it was ever included in those criteria anyway.

Basically, through some reason or another, the crew lost the plot. The crew became fixated at the lack of deceleration through no spoilers (and in TransAsia, lack of autobrakes), instead of commencing diagnosis of the problem in a timely and systematic manner. I'm sure there have been at least 1 case where the crew diagnosed the problem in a timely and systematic manner and that saved the day.

Quoting NAV20 (Reply 17):
As I said earlier, the simplest solution would probably be to remove the 'both engines to idle' requirement from the criteria for the deployment of autobrakes and ground spoilers. I still have no idea why it was ever included in those criteria anyway.

Great! Now how many accidents are you going to cause with that?
1. Late go-around on a single engine landing is now. So once the wheels touchdown, that's it, a/b goes on, and spoilers deploy... how do you override that? The number of crew not going all the way to TOGA and not checking the FMA in these situations is probably higher than the number of crew now putting all levers to idle on a single reverse landing. It's not a win/win situation in this case, you're just transferring the problem somewhere else.

2. All engine Go-around but due to crew panic they only put 1 throttle to TOGA, and then the other one perhaps a few seconds later. (ever heard of runway incursions at busy airports?) So, they can't go around and hit the obstacle that made them go-around in the first place?

3. Engine failure/fire after V1 (not sure what the procedure is to put the failed engine to idle)... so now you're gonna force airplanes on fire on the ground after V1? Geez!

And simulated single engine failure after V1 on the actual aircraft (where you put one engine to idle) will then not be available... That will yield to incidents when you have single engine failure after V1 due to lack of training/familiarity on this outside the simulator.

When you propose a solution, you check if the solution gives a problem in other scenarios. Such a kneejerk solution that you have possesses the risks I mentioned above. I prefer keep the current requirement to have the levers to idle on landing.

And then, also, your solution will still create a risk where the crew leaves 1 lever at CLB on an A/T landing, and the A/T makes it go all the way to CLB power or more, their eyes will be constantly checking the damn brake application indicator, brake temperature, PFD AND the engine instruments leading to an overload and slow reaction or worse, fixation. Having no brakes and starting the scan to see what's wrong is going to be faster and safer, coz they'll see the engine power application sooner without the fear of having brake fire... and maybe afterwards still check if spoilers were retracted if you decide to go-around... that is, if you allow for an autoretraction in such a situation...

Unless such a "proposal" is thoroughly thought out, even before one starts preaching about it, it's useless!

Now on a humourous note...

Quoting Starlionblue (Reply 19):
What's so hard about it?



Quoting NAV20, reply=Fictional reply:
It's an Airbus, that's why it's hard!

Mandala499
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halls120
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 11:28 pm

Quoting PU752 (Reply 11):
As a fellow pilot I have to say no, but captains always make the right decision on extreme situation (thats why the earned that position) , at least as a co-pilot no matter if my captain made the wrong decision at that time, I'll fully support him.

You're kidding, right?

I read this passage to my brother, who is a DL 767 captain, and he laughed his ass off.

He told me that when he was a FO, there were several flights that after they were on the ground, he called DL's chief pilot and asked that he never be assigned to fly with that particular captain again, as my brother considered him unfit to serve as pilot in command.

If you really think that the captain never makes a mistake, please let me know which airline you fly for, so that I can avoid it at all costs.
"Suppose you were an idiot. And suppose you were a member of Congress. But I repeat myself." Mark Twain, a Biography
 
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 11:30 pm

Quoting Zeke (Reply 15):
Quoting Iwok (Reply 14):Also, during a complex landing with a heavy bird, bad weather and a wet and slick runway I think it might be better if the pilots just focused on making a nice firm landing to get the squat sensors engaged, make sure both throttles are at idle and stomp on the auto brakes. In doing so you get all the things you need for a good stop, and most importantly the spoilers will deploy.
Spoken like a true armchair airline pilot......

Not an airline pilot myself (only fly light singles), but does the Airbus use squat sensors to detect a landing, or wheel spin-up? If the latter, on a slick runway, with hydroplaning, wheels may not spin up sufficiently to speed to allow spoiler deployment, etc.

Beech
 
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RE: TAM Plane Crashed In CGH Part 6

Fri Aug 03, 2007 11:34 pm

Quoting Mandala499 (Reply 13):
These things need to be tested in its practicality, tested for situations it is designed for, and tested for situations it is NOT designed for, and tested for nuisance warning generation and diagnosis. Then it would have to go through the human interface test and see whether it is useful or not...

I think you got a bit carried away there, mate. Airbus specifically said, "Airbus has developed a specific warning when one throttle is set to reverse while the other is above idle. This warning generates an ECAM warning "ENG x THR LEVER ABV IDLE", a continuous repetitive chime (CRC), and lights the red master warning light."

I think that, from that, we are entitled to assume that it had been fully developed, tested, determined to be 'useful' etc.? And it MIGHT have been MORE than useful in this case?
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 12:28 am

Quoting Jan Mogren (Reply 18):
What do you mean exactly?

Ahh, sorry for the lack of clarity: 1:00am is not a good time for me  Smile What I am basically saying is, I think it might be better to focus of having a nice firm landing, put all throttles to zero and slow down using spoilers and auto brakes. It just seems to me that one TR does not give you that much "bonus" stopping power, and does not seem to me to be worth the extra risk. It seems that the flight deck was very concerned with making sure they had the right TL in the correct position, but still there was an error.

Quoting Mandala499 (Reply 20):
I'm not sure what you're saying here, on the first sentence you're saying that a single T/R shouldn't be allowed? And the last sentence is you don't see how much the reverser is going to save you?

Correct: it seems to me that on a light twin a single TR has a bigger risk of accident that the extra stopping power is going to give you.

Does anyone know the particulars on how much additional reverse thrust is available from a singe TR?

Quoting Mandala499 (Reply 20):
Even with a single T/R, that single reverser may be the difference between 1 landing gear on the mud, or none... BUT, careless use will probably result in 1 landing gear or more having a quick or one way trip to the grass. Even if you have ALL T/Rs operating, landing on a wet runway in high cross winds can result in you going to the grass too if you're not careful.

There is careless use, and then there is use where the crew failed to follow a relatively complex set of procedures over a very short period of time.

Quoting Mandala499 (Reply 20):
There's a difference in trying to mitigate a risk due to the aircraft's system and a risk of crew not adhering to the procedures. For the latter, unless it is statistically significant, the solution will be as what you said later on...

I do understand your point; my point is that the more simple and robus the procedures are, the lower risk of error results. Over thousands and thousands of landings, a reduction in accident rate by 5% means a couple less bad accidents or even catastrophic crashes like the one we are talking about.

iwok
 
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 12:32 am

Quoting Mandala499 (Reply 20):

Unless such a "proposal" is thoroughly thought out, even before one starts preaching about it, it's useless!

I was waiting for someone to say, "BRING BACK THE FLIGHT ENGINEER !"

Quoting BeechNut (Reply 22):
Not an airline pilot myself (only fly light singles), but does the Airbus use squat sensors to detect a landing, or wheel spin-up? If the latter, on a slick runway, with hydroplaning, wheels may not spin up sufficiently to speed to allow spoiler deployment, etc.

RAD ALT and MLG squat switched for "on ground", the anti-skid uses wheel spin up.
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rfields5421
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 12:34 am

Quoting NAV20 (Reply 12):
During the next 8 seconds, the #1 thrust lever moved from the full reverse position to idle, then to the cruise position (+25 degrees TLA), and ultimately to the Take-Off/Go Around (TOGA) position, where it remained for 11 seconds before returning to the idle position. During this same period, the #2 thrust reverser remained at full reverse for 18 seconds, was moved to near the cruise position for about 2 seconds, and then returned to the idle position, concurrently with the #1 thrust lever. During the 11 seconds when the #1 engine was at TOGA thrust and the #2 engine was at full reverse, a right yawing motion occurred.

Question - does the FDR record the actual physical lever position with a sensor in the throttle quadrant, or the command system inputs to the engines/ throttle system?

Is it possible to input throttle commands without physically moving the thrust levers?

I mean, not in normal operations, but, does a computer control the throttle commands to the engines?

If a computer takes input from the throttle lever positions and sends commands to the engines - the extremely remote possibility of the computer malfunctioning must be considered.
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beechnut
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 12:34 am

Quoting Zeke (Reply 25):
RAD ALT and MLG squat switched for "on ground", the anti-skid uses wheel spin up.

Thanks.

I have been following the discussion on PPRUNE. Very interesting indeed to hear from veteran A320 drivers. Interestingly, even among the pros, there's an A vs B thing (though one guy swears by Douglas...)

Beech
 
Morvious
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 12:35 am

Quoting BeechNut (Reply 22):
Not an airline pilot myself (only fly light singles), but does the Airbus use squat sensors to detect a landing, or wheel spin-up? If the latter, on a slick runway, with hydroplaning, wheels may not spin up sufficiently to speed to allow spoiler deployment, etc.

If I recall right, the wheel spin-up is only for the braking and not the spoilers.
There is no need to brake if the wheels are hydroplaning or not even spinning at all.
have a good day,

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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 2:16 am

Quoting Mandala499 (Reply 13):
I really do not understand why do we need to add a warning on the fact that 1 in reverse and 1 in positive when it comes to the engine instrumentation.

Then I really don't understand why do we need altitude alerts when that information is available on the flight instruments too. I dunno, maybe because it's helpful?

Quoting Mandala499 (Reply 20):
1. Late go-around on a single engine landing is now. So once the wheels touchdown, that's it, a/b goes on, and spoilers deploy... how do you override that?

No brake pedal pressure, pilot increases thrust on at least one engine.

Quoting Mandala499 (Reply 20):
2. All engine Go-around but due to crew panic they only put 1 throttle to TOGA, and then the other one perhaps a few seconds later. (ever heard of runway incursions at busy airports?) So, they can't go around and hit the obstacle that made them go-around in the first place?

See above.

Quoting Mandala499 (Reply 20):
3. Engine failure/fire after V1 (not sure what the procedure is to put the failed engine to idle)... so now you're gonna force airplanes on fire on the ground after V1? Geez!

Aircraft in take-off configuration, no brake pedal pressure. Aircraft free to leave the ground as necessary.
 
azstagecoach
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 2:47 am

Question regarding spoilers:
a. why isn't more attention focused on why the pilot couldn't deploy the spoilers/speedbrakes? Yes, we know that the spoilers/speedbrakes would not deploy per A320 logic when one of the turbines had forward thrust. But why isn't there another method so that the pilot can apply speedbrakes in just such a situation, where a turbine isn't responding as the pilot intends?
b. Per Mandala's post, there is also the issue of a ten second wait after auto-retract of the spoilers due to an interrupting event. Isn't this far too long to have to wait for the spoilers to re-extend, especially given the sequence played out at CGH? Is it possible that the spoilers did in fact retract due to one of these events, or is it certain that the spoilers never extended in the first place?
 
dragon6172
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 2:48 am

Quoting Khobar (Reply 29):
Quoting Mandala499 (Reply 13):
I really do not understand why do we need to add a warning on the fact that 1 in reverse and 1 in positive when it comes to the engine instrumentation.

Then I really don't understand why do we need altitude alerts when that information is available on the flight instruments too. I dunno, maybe because it's helpful?

I agree Khobar. Not to mention if you only looked at the engine instrumentation, an engine in full reverse could have the same N1, TGT, etc etc of the engine in positive thrust. Sure in a single TR landing that should register as wrong, but most of the times your engine readings are matched up, so maybe it would not light the bulb in a pilots head.

[Edited 2007-08-03 19:50:49]
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Starlionblue
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 3:05 am

Quoting Iwok (Reply 24):
It seems that the flight deck was very concerned with making sure they had the right TL in the correct position, but still there was an error.

Yepp. Note that the following assumes the pilots screwed up: Changing the aircraft because a mistake was made doesn't fix the poor airmanship issue. Improving training and procedures does.

As I have repeatedly said: The safest aircraft in the world can be crashed by a determined pilot.

Quoting RFields5421 (Reply 26):
Is it possible to input throttle commands without physically moving the thrust levers?

Sure. Just use the autothrottle functionality. Inputs come from the glareshield panel or from the FMC. (Very simplified)

Quoting RFields5421 (Reply 26):
I mean, not in normal operations, but, does a computer control the throttle commands to the engines?

Yes. On pretty much all modern airliners you will have FADEC (Full Authority Digital Engine Control). I believe it became pervasive in the 80s.

Quoting RFields5421 (Reply 26):

If a computer takes input from the throttle lever positions and sends commands to the engines - the extremely remote possibility of the computer malfunctioning must be considered.

Of course. But note that FADEC technology is decades old and quite mature.

Quoting Azstagecoach (Reply 30):
a. why isn't more attention focused on why the pilot couldn't deploy the spoilers/speedbrakes? Yes, we know that the spoilers/speedbrakes would not deploy per A320 logic when one of the turbines had forward thrust. But why isn't there another method so that the pilot can apply speedbrakes in just such a situation, where a turbine isn't responding as the pilot intends?

I would think that is one of the focal points of the investigation.
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David L
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 3:37 am

Quoting Iwok (Reply 24):
It seems that the flight deck was very concerned with making sure they had the right TL in the correct position, but still there was an error.

And yet it seems TAM's procedures call for both reversers to be selected whether one's inop or not. I.e. the crew may have made it more complicated than it should have been. That's not a sleight on the crew, just an observation that a crew unnecessarily adding complications might be more of a training issue.

Quoting NAV20 (Reply 17):
Mandala, the short answer is that (from the transcript) the pilots appear to have been utterly confused by what was happening - or rather NOT happening.

I know it's very easy for me to ask in hindsight while sitting comfortably at home but, If the deceleration doesn't "feel right" on a short, wet runway with one reverser inop and you don't know what's "not happening", why not immediately shove both levers to TOGA, go around then, if necessary, divert to a more suitable runway, instead of trying to work out what's not happening? Again, I'm not saying the crew were stupid but isn't that kind of thing meant to be second nature on any type, i.e. a training issue?
 
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Starlionblue
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 3:53 am

Quoting David L (Reply 33):
know it's very easy for me to ask in hindsight while sitting comfortably at home but, If the deceleration doesn't "feel right" on a short, wet runway with one reverser inop and you don't know what's "not happening", why not immediately shove both levers to TOGA, go around then, if necessary, divert to a more suitable runway, instead of trying to work out what's not happening? Again, I'm not saying the crew were stupid but isn't that kind of thing meant to be second nature on any type, i.e. a training issue?

Yes.

Quoting David L (Reply 33):
Quoting Iwok (Reply 24):
It seems that the flight deck was very concerned with making sure they had the right TL in the correct position, but still there was an error.

And yet it seems TAM's procedures call for both reversers to be selected whether one's inop or not. I.e. the crew may have made it more complicated than it should have been. That's not a sleight on the crew, just an observation that a crew unnecessarily adding complications might be more of a training issue.

Yes. And it also seems to be an accepted procedure on the 32x to select both reversers. As evidenced by the message sent by Airbus.
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spacecadet
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 4:31 am

Quoting Starlionblue (Reply 34):
Quoting David L (Reply 33):
know it's very easy for me to ask in hindsight while sitting comfortably at home but, If the deceleration doesn't "feel right" on a short, wet runway with one reverser inop and you don't know what's "not happening", why not immediately shove both levers to TOGA, go around then, if necessary, divert to a more suitable runway, instead of trying to work out what's not happening? Again, I'm not saying the crew were stupid but isn't that kind of thing meant to be second nature on any type, i.e. a training issue?

Yes.

Not sure about that.

Pilots are trained to ignore what "feels right" and go by what their instruments tell them. Plenty of accidents have been caused by pilots who thought something "felt" a certain way and ignored what their instruments were telling them. In every case, the instruments were right. I know some pilots will probably say they can tell which way their airplane's pointed and how fast it's going by the way their butt feels in the seat, but as the two 757 crashes that involved the pitot sensors being covered up back in the 90's proved, that's not really the case. Those two crews were actually right for disbelieving their instruments, but their "feel" for the airplane was so unreliable that they crashed an otherwise normally functioning airplane anyway.

I would think it would be much more dangerous for a pilot to do a post-touchdown go-around based on "feel" than it would for him to simply scan his instruments and try to figure out what's really happening. The law of unintended consequences would almost guarantee that you'd have an accident or two based on pilots initiating late and unnecessary go-arounds when their plane was actually slowing down satisfactorily, and doing so believing that their airplane has a potential problem that it really doesn't. After all, it's a lot to ask of a pilot for him to work out runway distance remaining and takeoff weights and balances in his head as he's rolling down a wet runway, then not knowing what (in his mind) caused the problem on the last touchdown, which will make the next touchdown into an emergency situation that it shouldn't be. The last thing anybody wants after any accident is for the cure to be worse than the disease.

There are really only two possible root causes for this accident, both of which have fairly simple solutions it seems to me:

1. The pilot failed to retard the throttle to idle as per procedure. Pilot error. Solution: better training to reduce the chance of error, potentially some ergonomic changes to the cockpit warning systems and/or the throttle levers.

2. The computer misread the throttle position. Software error. Solution: identify the software bug and reprogram to remove it. (This would actually be somewhat disturbing to me if it ends up being the cause; what other bugs still lurk that could bring down another airplane?)

The bottom line is if the throttle was not at idle, these are really the only two things that could cause it, and their solutions are pretty straightforward. There are probably going to be some secondary factors and those should be addressed as well, but there's not going to be anything about this that's going to require a complete change in philosophy in how pilots are trained. Instruments can and should be relied upon, not "feel".
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 4:39 am

Quoting NAV20 (Reply 17):
As I said earlier, the simplest solution would probably be to remove the 'both engines to idle' requirement from the criteria for the deployment of autobrakes and ground spoilers. I still have no idea why it was ever included in those criteria anyway.

I'm no pilot. I'm just an IT guy with a degree in mechanical engineering. But it seems perfectly obvious to me why the system is set up thusly.

Thrust provides the power that flies the airplane. It seems to me that there may be precedent assigned to such; that is, if there is thrust, the pilot wants power to propel the airplane. I have no idea why you would ask the airplane to do anything counter to this mandate. It strikes me as inherently contradictory to employ devices which stop the airplane when the primary power source for the airplane is engaged, because there is about 100 knots of airspeed where the aircraft has huge kinetic energy, but cannot safely FLY.

In fact, I don't see how "go" and "stop" can possibly be given equal footing. One is clearly more important than the other. Perhaps a problem we non-pilots face is that the only transportation machine we operate is our car, where "stop" is clearly superior to "go." We can nearly always get out of trouble by stopping, and we can almost never get into trouble if we are not moving.

In an airplane, SOP for many situations seem to reverse this arrangement. Engine failure after V1? GO! Unstable approach? GO! Can't stop the airplane after you get it on the ground? GO! Again, this seems completely sensible to me. Airspeed is life, so if you're going to err with operations and/or systems, you do it on the side of airspeed. And how do you get airspeed? Aside from a dive, thrust.
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David L
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 4:44 am

Just to be clear, I'm not saying the TAM crew should have gone around, just that it would seem that training should already be in place that reduces the need for a "ground override" or additional thrust warnings on Airbuses only.

Quoting Spacecadet (Reply 35):
Pilots are trained to ignore what "feels right" and go by what their instruments tell them. Plenty of accidents have been caused by pilots who thought something "felt" a certain way and ignored what their instruments were telling them.

So, take the safer option instead of hoping you can figure out what's wrong before you run out of space and time.

Quoting Spacecadet (Reply 35):
I would think it would be much more dangerous for a pilot to do a post-touchdown go-around based on "feel" than it would for him to simply scan his instruments and try to figure out what's really happening.

Really? How much time would you assign to trouble-shooting as the available runway flashes past your windscreen? Is a prompt go-around as dangerous as running out of runway?
 
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Starlionblue
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 5:10 am

Quoting David L (Reply 37):
Quoting Spacecadet (Reply 35):
I would think it would be much more dangerous for a pilot to do a post-touchdown go-around based on "feel" than it would for him to simply scan his instruments and try to figure out what's really happening.

Really? How much time would you assign to trouble-shooting as the available runway flashes past your windscreen? Is a prompt go-around as dangerous as running out of runway?

I can see both sides of the argument.


Then again, you have to consider the short and wet runway. As Captain Click eloquently stated back in Part Deux or something, pretty much ANYTHING not nominal would make him go around in these situations.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
ContnlEliteCMH
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 10:44 am

Quoting Starlionblue (Reply 38):
As Captain Click eloquently stated back in Part Deux or something, pretty much ANYTHING not nominal would make him go around in these situations.

Right. And this is consistent with "go" being more important than "stop." It is perfectly sensible that the *default* behavior of the 'Bus is to avoid spoilers and autobrake so long as at least one of the engines is commanded to thrust above idle. Plus, there is safety in the air. There's really nothing to hit, and by definition controlled flight is... controlled. When you're hurtling down a wet runway, the wheels are lightly loaded due to lift, there is no additional drag due to spoilers, and the worst thing that can happen is that you can't stop the airplane, but you can't make it fly, either. That's a great definition of "out of control" for an airplane and people get killed that way. If you can't already make it stop, at least you can make it go.
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zeke
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 11:57 am

Quoting RFields5421 (Reply 26):

Question - does the FDR record the actual physical lever position with a sensor in the throttle quadrant, or the command system inputs to the engines/ throttle system?

Yes

Quoting Khobar (Reply 29):

Aircraft in take-off configuration, no brake pedal pressure. Aircraft free to leave the ground as necessary.

A go around/aborted landing is not done in takeoff configuration, you should get a master caution saying stab trim not set. Full flap is not takeoff config either.

Quoting Dragon6172 (Reply 31):

I agree Khobar. Not to mention if you only looked at the engine instrumentation, an engine in full reverse could have the same N1, TGT, etc etc of the engine in positive thrust. Sure in a single TR landing that should register as wrong, but most of the times your engine readings are matched up, so maybe it would not light the bulb in a pilots head.

The letters REV in the middle of the EPR or N1 indication, it was picked up by the crew "reverse number one only" was on the CVR.
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khobar
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 12:12 pm

Quoting Zeke (Reply 40):
A go around/aborted landing is not done in takeoff configuration, you should get a master caution saying stab trim not set. Full flap is not takeoff config either.

Read what he wrote: "3. Engine failure/fire after V1 (not sure what the procedure is to put the failed engine to idle)... so now you're gonna force airplanes on fire on the ground after V1? Geez!"

I replied, "Aircraft in take-off configuration, no brake pedal pressure. Aircraft free to leave the ground as necessary."

Am I incorrect?
 
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zeke
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 12:32 pm

Quoting Khobar (Reply 41):
Am I incorrect?

Yes for that, but not for the others, anything after V1, don't do anything till 400' (no radio, no movement of thrust levers unless to TOGA, no fire bottles, no ecam), fly the aircraft, get gear up, trim it, and engage the autopilot. An engine on fire is still producing thrust, use that thrust to get you away from the ground.

The problem with your solution, is that pilots do increase thrust all the time in those situations, say in gusty wind conditions the pilot increases thrust just before touchdown (with autothrust on or off) you are saying to program that to be a go-around, when they want to land the aircraft. Also for a bounce at landing, they do happen, you need to be careful of any ramifications.
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NAV20
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 1:04 pm

Quoting ContnlEliteCMH (Reply 39):
the worst thing that can happen is that you can't stop the airplane, but you can't make it fly, either. That's a great definition of "out of control" for an airplane and people get killed that way.

Surely that's exactly what happened?

The lack of spoilers and autobrakes won't have helped, but the thing that finished them off (made a serious accident certain) was the fact that the starboard engine didn't just settle to 'just above idle' power. It spooled up to CLIMB power, or something close to it. This despite the fact that by that time the pilots had deployed full reverse thrust on the port engine, on that short runway there was never any question of a go around after that.

As far as I know go-arounds after touchdown are rare - the more normal situation is a 'missed approach' while still in the air. Surely, once the wheels are down and reverse thust is deployed, the 'systems' should 'accept' that landing is intended unless the pilot tells them different (which he would do, first of all, by cancelling the reverse thrust?).
"Once you have flown, you will walk the earth with your eyes turned skywards.." - Leonardo da Vinci
 
dragon6172
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 1:25 pm

Quoting Zeke (Reply 40):
The letters REV in the middle of the EPR or N1 indication, it was picked up by the crew "reverse number one only" was on the CVR.

And yet they didnt notice the N1 indcation right next to it was not at idle?
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zeke
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 1:36 pm

Quoting NAV20 (Reply 43):

The lack of spoilers and autobrakes won't have helped, but the thing that finished them off (made a serious accident certain) was the fact that the starboard engine didn't just settle to 'just above idle' power. It spooled up to CLIMB power, or something close to it. This despite the fact that by that time the pilots had deployed full reverse thrust on the port engine, on that short runway there was never any question of a go around after that.

When you are on the ground, we use thrust levers to taxi an aircraft, we can taxi an aircraft with just one engine, which some operators do to save fuel. Also if the APU is unavailable, doing a cross bleed start, you need to increase power above IDLE to supply bleed to start the other engine.

With autothrust off, the thrust lever angle is the command thrust level, on a Boeing or Airbus. It is possible to have one in reverse and one above idle in a Boeing as well, the problem with the Boeing's, is that this function varies between models, where it is consistent across the Airbus models. For example, another problem which has almost lead to numerous accidents is the auto thrust disconnect and toga buttons are not in the same place on Boeing's, BA came very very close to loosing a 744 on landing when a pilot transition off a 767 went to disconnect the autothrust on finals, except the autothrust disconnect buttons position on a 767 is the toga button on a 744, very close to another A300 style accident. Did Boeing change anything as a result of that incident....nope..

Quoting NAV20 (Reply 43):

As far as I know go-arounds after touchdown are rare - the more normal situation is a 'missed approach' while still in the air. Surely, once the wheels are down and reverse thust is deployed, the 'systems' should 'accept' that landing is intended unless the pilot tells them different (which he would do, first of all, by cancelling the reverse thrust?).

Would be a couple a day somewhere in the world, bounced landings, go around off a CAT 3 landing, touch and gos etc.

How does the aircraft know which a pilot wants to do, go or stop ? one thrust lever says go, one says stop, as pilots we are trained to be go minded, not stop minded, same with the aircraft.

What if the scenario was reversed, what would happen if they were training on the same runway, doing touch and goes, and the pilot inadvertently selects reverse and spools the other engine up, the aircraft is above V1, and running out of runway, you would have it that they run off the end, rather than get airborne again ?

Where it could be saved by going TOGA on both, one needs a lot less runway to accelerate by 30 kts, than to stop from 110kt.
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
khobar
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 1:58 pm

Quoting Zeke (Reply 42):
The problem with your solution, is that pilots do increase thrust all the time in those situations, say in gusty wind conditions the pilot increases thrust just before touchdown (with autothrust on or off) you are saying to program that to be a go-around, when they want to land the aircraft. Also for a bounce at landing, they do happen, you need to be careful of any ramifications.

Pilots increase thrust AND apply pressure to the brakes just before touchdown? I mentioned braking effort by the pilots as a logic input.
 
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zeke
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 2:11 pm

Quoting Khobar (Reply 46):

Pilots increase thrust AND apply pressure to the brakes just before touchdown? I mentioned braking effort by the pilots as a logic input.

What if it was a rudder input with someone with their foot too far up the rudder pedal ? What happens if they were trying to remove residual brake pressure whilst airborne ?

On an normal landing, no brake pedal pressure is used at all until a much lower speed to disengage the autobrake.
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
iwok
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 2:21 pm

Quoting NAV20 (Reply 43):
Surely that's exactly what happened?

The lack of spoilers and autobrakes won't have helped, but the thing that finished them off (made a serious accident certain) was the fact that the starboard engine didn't just settle to 'just above idle' power. It spooled up to CLIMB power, or something close to it. This despite the fact that by that time the pilots had deployed full reverse thrust on the port engine, on that short runway there was never any question of a go around after that.

NAV, I am trying to understand what the general consensus is on what happened. Here is my understanding.

1) normal aproach
2) potentially soft landing on wet runway (squat switches may not have been actuated?)
2a) both TL set to idle
3) #1 TR deployed
4) #1 TL set to 100% RT setting
5) #2 TL set slightly above idle (perhapse the #2 was accidentally hit?)
6) spoilers and auto brakes do not deploy
7) #2 thrust increases to CLIMB power (is this correct?)

Now. What were the correct TL settings supposed to have been?
#1 set to 100% RT, RT deployed
#2 set to idle

OR ??

iwok
 
NAV20
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RE: TAM Plane Crashed In CGH Part 6

Sat Aug 04, 2007 3:43 pm

Iwok, the only thing we can be reasonably certain of is that the touchdown was 'normal,' in the sense that it was soon after the aircraft crossed the threshold of the runway, and at normal landing speed. I think it's fair to assume that the squat switches etc. 'accepted' that it had landed, otherwise (as far as I know) reverse thrust could not have been deployed.

Pretty well everything else is supposition. As far as I know the pilot SHOULD, according to normal principles of flying plus the special circumstances of the A320 design, have:-

1. Disconnected the autothrust.
2. Flared (slightly raised the nose).
3. Pulled both throttle levers back to idle.
4. Kept the wings level until touchdown.
5. Lowered the nosewheel.
6. Pulled both levers back to 'reverse idle' and then to full reverse.

We can pretty well be sure, from the behaviour of the aeroplane, that 2, 4, and 5 happened. For the rest, we are dependent on the evidence of the Flight Data Recorder. That says that only the lefthand lever was pulled back, and subsequently pulled further back; while the righthand lever remained in the CLIMB detent (that is, effectively at 'cruise' power). I believe (someone correct me if wrong) that if the lever remains in 'climb' with the autothrust disconnected, the engine reverts to its last recorded power setting (which would have been the power required to maintain landing speed in an approach with gear down, full flaps extended, etc. - say about 55% power.

http://www.flightglobal.com/articles...etard-right-hand-thrust-lever.html

Quoting Iwok (Reply 48):
Now. What were the correct TL settings supposed to have been?
#1 set to 100% RT, RT deployed
#2 set to idle

Up to 2002 (the Phoenix accident) the rule with one reverser inop. was inop. side to idle, operating side to 'reverse idle' and back to reverse power. At some time after that, Airbus changed the rule and it is now BOTH levers all the way back to reverse power.

That's something the investigators will have to check carefully. The original reason for not reversing the inop. side was, of course, that unless the reversers deployed, the engine would be chucking out forward thrust instead. I believe that the actual maintenance procedure for an inop. reverser is that it is disconnected and locked/pinned so that it cannot deploy; and I've read that the controls are changed (either mechanically or by means of software, I don't know which) so that, even though the lever is set to 'max. reverse thrust,' the locked-out engine stays at 'idle' power.

The investigators will have to check that all that was done properly - and. of course, that it all worked properly.

[Edited 2007-08-04 08:48:15]
"Once you have flown, you will walk the earth with your eyes turned skywards.." - Leonardo da Vinci

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