TAM A320 crash at Congonhas, Brazil
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1) I too wondered about the increase in engine noise Fox niner mentions, but I put it down (in total ignorance of the AB system
) to the still engaged A/T responding to a need for thrust to maintain Vref+??. I was assuming that although the system is 'retard' minded that since No 2 T/L was thought to be still set to 'limit' to CLB N1 it might be speed sensitive?
This would, I thought, probably explain the attempt by No2 engine to maintain speed (.6 secs) after No 1 has been idled?
2) Apologies if I have missed it in the now 1100+ posts, but when A/T disconnects at T/L idle, I understand the engine would be accelerated to match the T/L position? If we have been flying an A/T approach, and the T/Ls do not actually 'move', what decides the actual position of the No2 T/L - in other words, where would No 2 T/L be set on this approach, and if it is indeed the CLB position, would the engine then accel to CLB limit N1 on disconnect?
) to the still engaged A/T responding to a need for thrust to maintain Vref+??. I was assuming that although the system is 'retard' minded that since No 2 T/L was thought to be still set to 'limit' to CLB N1 it might be speed sensitive? This would, I thought, probably explain the attempt by No2 engine to maintain speed (.6 secs) after No 1 has been idled?
2) Apologies if I have missed it in the now 1100+ posts, but when A/T disconnects at T/L idle, I understand the engine would be accelerated to match the T/L position? If we have been flying an A/T approach, and the T/Ls do not actually 'move', what decides the actual position of the No2 T/L - in other words, where would No 2 T/L be set on this approach, and if it is indeed the CLB position, would the engine then accel to CLB limit N1 on disconnect?
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@DReamLand
Perhaps you can reconcile these two posts?
http://www.pprune.org/forums/showpos...postcount=1088
http://www.pprune.org/forums/showpos...postcount=1123
My understanding is that there is no manual GS activation of the GS on the A320, and that even the speedbrake function (which controls only some of the panels) is inhiobited in config Full (i.e. landing). You've referred to manual extension and then said it isn't possible.
Is there any DIRECT control of the spoilers when on-ground in config Full which is not an indirect means reliant on TL movement etc?
Perhaps you can reconcile these two posts?
Mad, speedbrake in Airbus speak is a deceleration tool while in flight (spoilers 2,3 and 4), A320 gives you 50% of speed brakes while on autopilot, full speed brakes with A/P disconnected, when config full is selected, speed brakes are inhibited, slightly different system on A321.
.
Ground Spoilers:
(spoilers 1 through 5) ARMED - With both thrust levers at idle, and two main gears compressed.
.
(1 through 5) NOT ARMED - 1 REV, 1 idle or two REV (any flaps, 2 main gears compressed).
.
Manually Extended- CONFIG FULL: spoilers 1, CONFIG 0-3: spoilers 1-4
.
Ground Spoilers:
(spoilers 1 through 5) ARMED - With both thrust levers at idle, and two main gears compressed.
.
(1 through 5) NOT ARMED - 1 REV, 1 idle or two REV (any flaps, 2 main gears compressed).
.
Manually Extended- CONFIG FULL: spoilers 1, CONFIG 0-3: spoilers 1-4
The lever is used for SPEED BRAKE control, an in the air function only, as was mentioned by another poster, the lever does not move during landing, Airbus pilots don't associate this lever with GROUND SPOILERS, if the GROUND SPOILERS fail to deploy on landing, it's because of thrust lever position, moving the lever back for some kind of manual activation is not an option.
My understanding is that there is no manual GS activation of the GS on the A320, and that even the speedbrake function (which controls only some of the panels) is inhiobited in config Full (i.e. landing). You've referred to manual extension and then said it isn't possible.
Is there any DIRECT control of the spoilers when on-ground in config Full which is not an indirect means reliant on TL movement etc?
AT Disconnect
@BOAC
Explanation : Airbus - From link posted earlier referring to TW Incident.
"The disconnection logic is such that ATHR disconnection is normally obtained
at touch down when both throttles are set to IDLE, without ATHR warning .
If not, another ATHR reset condition can allow the ATHR to be disengaged :
-If the THR TARGET feedback of one FADEC is different by 0.15 EPR from the
ATHR EPR TARGET limited to the corresponding EPR TLA, the ATHR is
disconnected after 1.8 sec. This condition triggers the ATHR warning. This
condition has been triggered before the previous one during that landing.
The FADEC transmission of the EPR TLA becomes NCD when the
corresponding throttle is selected in reverse range , the FMGC ARINC
acquisition behaviour (per design) in case of NCD is to keep the last EPR TLA
valid value (0.98 during lab test in the conditions of the TAN landing). On an
other hand the FADEC EPR TARGET FEEDBACK in reverse is reduced to
about 0.75 EPR. Such a difference is due to the fact that: when no alpha floor
condition is present, the FADEC EPR TARGET FEEDBACK is upper limited to
EPR TLA which is set, when TLA is at or below idle, to EPR IDLE. The EPR
IDLE is reduced by 0.2 when the thrust reverser has deployed more than 15%.
Consequently the EPR comparison becomes invalid and the ATHR is
disconnected after 1.8 sec with the corresponding warning .That involuntary
ATHR disconnection allowed the thrust to be frozen on engine2 whose lever
was at CLB notch !"
Thrust therefore would NOT reach climb power.
Max Tow
I think the 'Reverser no1 only' call would/could be a serious HF case if it was made prior to touchdown. Not true in this case and was made after 'sound of moving thrust lever'.
There is no sound of the 'Spoiler lever' being moved, so no spoilers no matter what could or could not be deployed. They would (if my understanding is correct) got some spoilers if they had move the SB lever. Not enough for sure but anything is better than nothing.
Tankering fuel in CGH on a marginal runway, is this wise? Especially when we.
Jim
Explanation : Airbus - From link posted earlier referring to TW Incident.
"The disconnection logic is such that ATHR disconnection is normally obtained
at touch down when both throttles are set to IDLE, without ATHR warning .
If not, another ATHR reset condition can allow the ATHR to be disengaged :
-If the THR TARGET feedback of one FADEC is different by 0.15 EPR from the
ATHR EPR TARGET limited to the corresponding EPR TLA, the ATHR is
disconnected after 1.8 sec. This condition triggers the ATHR warning. This
condition has been triggered before the previous one during that landing.
The FADEC transmission of the EPR TLA becomes NCD when the
corresponding throttle is selected in reverse range , the FMGC ARINC
acquisition behaviour (per design) in case of NCD is to keep the last EPR TLA
valid value (0.98 during lab test in the conditions of the TAN landing). On an
other hand the FADEC EPR TARGET FEEDBACK in reverse is reduced to
about 0.75 EPR. Such a difference is due to the fact that: when no alpha floor
condition is present, the FADEC EPR TARGET FEEDBACK is upper limited to
EPR TLA which is set, when TLA is at or below idle, to EPR IDLE. The EPR
IDLE is reduced by 0.2 when the thrust reverser has deployed more than 15%.
Consequently the EPR comparison becomes invalid and the ATHR is
disconnected after 1.8 sec with the corresponding warning .That involuntary
ATHR disconnection allowed the thrust to be frozen on engine2 whose lever
was at CLB notch !"
Thrust therefore would NOT reach climb power.
Max Tow
I think the 'Reverser no1 only' call would/could be a serious HF case if it was made prior to touchdown. Not true in this case and was made after 'sound of moving thrust lever'.
There is no sound of the 'Spoiler lever' being moved, so no spoilers no matter what could or could not be deployed. They would (if my understanding is correct) got some spoilers if they had move the SB lever. Not enough for sure but anything is better than nothing.
Tankering fuel in CGH on a marginal runway, is this wise? Especially when we.
Jim
Last edited by James7; 4th Aug 2007 at 18:08.
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The FWC says RETARD twice, then there is an INCREASE in engine noise??? After which the GPWS says RETARD (obviously)
So how am I supposed to read this? The computers want the thrust levers to be retarded, but instead there is can INCREASE in engine noise!?! The significant thing here is that all this happens when the aircraft is still airborne. Touchdown happens at 18:48:26.3
So how am I supposed to read this? The computers want the thrust levers to be retarded, but instead there is can INCREASE in engine noise!?! The significant thing here is that all this happens when the aircraft is still airborne. Touchdown happens at 18:48:26.3
What you see there is the application of reverse thrust as per FCOM 3, at main wheel touch down, before nose wheel, the increase in noise is the reverse.
"Retard" comes from the FWC, not GPWS, I suspect something is wrong with the transcript translation with the "18:48:25.5 GPWS retard".
Jim,
Nice work on the plagiarism, that is word for word from page 167 of the Taiwanese report that you posted a link to earlier ... did you consider citing the reference you copied and pasted from ? Any other posts from you that contain material from others that we should know about ?
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from the post :http://www.pprune.org/forums/showthread.php?t=146445
A clairvoyant
Thanks for your reply guys.
I actually met up with a 330 pilot and
had a discussion about this topic.
He had told me that airbus designed the spoilers to activate slowly for the comfort of the passengers. I think that is quite stupid especially landing on a wet runway you would want to spoil as much lift as possible and get the wheels firmly on the ground.
Obviously there hasnt been a problem so far.
I actually met up with a 330 pilot and
had a discussion about this topic.
He had told me that airbus designed the spoilers to activate slowly for the comfort of the passengers. I think that is quite stupid especially landing on a wet runway you would want to spoil as much lift as possible and get the wheels firmly on the ground.
Obviously there hasnt been a problem so far.
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I find that comment hard to give credence to - when designing for performance we'll squeeze every last ounce out of the design we can - I can't imagine anyone's going to give up landing distance for something like that.
Are you sure he wasn't referring to in-air deployment of speedbrakes - where a slower deployment might reduce the 'g' bump on deployment, and might be a comfort, or even handing, issue (at least one of our aircraft has low rate spoiler deployment in-air for much those reasons) - rather than in GLD mode?
Are you sure he wasn't referring to in-air deployment of speedbrakes - where a slower deployment might reduce the 'g' bump on deployment, and might be a comfort, or even handing, issue (at least one of our aircraft has low rate spoiler deployment in-air for much those reasons) - rather than in GLD mode?
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Well James, plagiarised or not, was that an explanation or a lecture? Do I understand that the 'TAN' landing is the Taiwanese one or a mis-spelt 'TAM'? Can anyone explain in words I can understand what the likely N1 or EPR achieved on No2 in CGH would have been?
- please!
- please!
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Re Fuel Tankering
IIRC the figure of 3 to 4 tonnes extra was quoted (a long way back). From the QRH increase in Vapp is 1 kt per tonne, and on a Wet runway an extra 75 m (approx) increase in actual landing distance would result for 4 tonnes extra. The figure for a 6.3 mm (1/4 inch) of Water runway is approx 118 m extra.
Hard to know at this distance whether the skipper took extra for weather or fuel policy .. if the latter he might still have taken an extra something for wx or other local factors.
TP
Hard to know at this distance whether the skipper took extra for weather or fuel policy .. if the latter he might still have taken an extra something for wx or other local factors.
TP
Last edited by TyroPicard; 4th Aug 2007 at 17:29. Reason: Clarity
@Zeke
Correct, but it was SO obvious and i already posted one link as a few others had and already mentioned just a few posts earlier it was from AB. My mistake for not putting the link in. Hey at least you realised. Also it seems that many posters had not followed the link hence the post.
Thanks for the info and amended.
Jim
Thanks for the info and amended.
Jim
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Transcript of TAM Voice recorder
TAM A320 crash - full transcript from cockpit voice recorder
By Michael Targett
TAM A320 7/17/07 Sao Paulo Brazil
Cockpit Voice Recorder – Transcript
Start of Transcript
18:18:24.4 (all times are local time) [start of recording]
18:18:24.5
PA-1 [captain makes speech to passengers]
18:18:53.4
CAM-? [sound of whistling]
18:20:25.0
CAM [sound of flight attendant door open request]
18:20:28.1
CAM-1 is ok?
18:20:29.7
CAM-3 [flight attendant says that everything in the cabin is OK, and then asks where will they be landing]
18:20:33.3
CAM-1 I have just informed.
18:20:34.7
CAM-3 I didn't hear - sorry - her talking.
18:20:37.7
CAM-1 but she heard, Congonhas.
18:20:39.3
CAM-3 is it Congonhas? It’s great, so. she might have heard. thank you.
18:43:04.3
HOT-1 remember, we only have one reverse.
18:43:06.9
HOT-2 yes... only the left.
18:43:24.0
HOT-1 glideslope, LOC blue... LOC star. [LOC star means an asterisk is displayed on the FMA, which means the loc capture]
18:43:26.6
HOT-2 checked.
18:43:27.1
HOT-1 autopilot one plus two.
18:43:29.4
HOT-1 flaps one.
18:43:30.7
HOT-2 speed checked.
18:43:36.7
HOT-1 clear status.
18:43:41.8
HOT-2 clear status.
18:43:43.8
HOT-2 clear.
18:43:48.2
RDO-2 going to intercept the localizer, TAM three zero five four.
18:43:52.2
APP TAM three zero five four, reduce speed for the approach... and call the tower on frequency one two seven point one five, good afternoon.
18:44:00.0
RDO-2 one two seven one five, over.
18:44:01.7
HOT-1 good afternoon.
18:44:06.4
HOT-1 flaps two.
18:44:08.1
CAM-2 speed checked.
18:44:20.0
HOT-2 flaps at two.
18:44:22.3
RDO-2 Sao Paulo tower, this is TAM three zero five four.
18:44:26.1
TWR TAM three zero five four, reduce minimum speed for approach, the wind is north with zero six. I will report when clear three five left.
18:44:33.4
RDO-2 good evening, reducing to the minimum possible [speed].
18:44:36.3
HOT-1
landing gear down.
18:44:37.7
HOT-2 landing gear down.
18:44:53.9
HOT-1 flaps three.
18:44:55.1
HOT-2 speed checked.
18:44:57.4
HOT-2 flaps three.
18:45:03.9
HOT-1 flap full.
18:45:05.7
CAM-2 speed checked, flaps full.
18:45:10.6
HOT-1 standby final checklist
18:45:12.0
HOT-2 standing by.
18:45:12.9
CAM-1 glide star, set missed approach altitude.
18:45:15.0
CAM-2 ALT * *.
18:45:21.0
CAM-2 six thousand feet.
18:45:44.0
CAM [sound of windshield wipers operating]
18:45:52.1
CH2 [sound of outer marker beacon heard on channel 2]
18:46:03.2
HOT-1 final checklist.
18:46:04.6
HOT-2 final checklist, passing DIADEMA [name of the outer marker beacon]
18:46:10.4
PA-2 cabin crew, clear to land. [prepare for landing]
18:46:14.0
CAM-2 cabin crew.
18:46:15.2
CAM-1 advised.
18:46:16.0
CAM-2 auto thrust.
18:46:17.8
CAM-1 speed.
18:46:20.0
CAM-2 * *.
18:46:21.1
CAM-1 landing no blue.
18:46:22.6
CAM-1 ECAM MEMO [Electronic Centralized Aircraft Monitor - check memo status]
18:46:23.8
HOT-1 landing, no blue.
18:46:24.9
HOT-2 landing no blue.
18:46:26.1
HOT-1 okay?
18:46:26.7
HOT-2 okay... what?
18:46:28.6
HOT-2 okay.
18:46:30.8
HOT-? *.
18:46:30.8
HOT-2 final checklist complete.
18:46:33.8
CAM-1 runway in sight, landing.
18:46:41.7
CAM-1 ask him [the tower] about the rain condition, the runway condition, and if the runway is slippery.
18:46:57.0
RDO-2 TAM on final approach, two miles away. could you confirm conditions?
18:47:01.7
TWR it's wet, and it is slippery. I will report three five left clear, three zero five four.
18:47:06.1
RDO-2 already on final.
18:47:07.5
TWR the aircraft is starting the departure.
18:47:10.7
HOT-1 wet and slippery!
18:47:22.0
HOT-2 the aircraft is starting the takeoff run.
18:47:34.3
TWR TAM three zero five four, three five left, clear to land, the runway is wet, and is slippery and the wind is three three zero at eight. knots.
18:47:40.6
HOT-2 three three zero at eight, is the wind.
18:47:42.9
HOT-1 checked.
18:47:43.9
TWR three zero five four?
18:47:45.3
RDO-2 three zero five four, roger.
18:47:46.4
FWC four hundred.
18:47:49.8
HOT-1 is the landing clear?
18:47:50.7
HOT-2 clear to land.
18:47:52.3
HOT-1 land green, manual flight.
18:47:53.7
CAM [sound of autopilot disconnect tone]
18:47:54.1
HOT-2 checked.
18:47:54.8
HOT-1 inhibit the glide [GPWS aural warning] for me please.
18:47:55.7
CAM [sound of triple click indicating reversion from CAT II or III to CAT I approach mode (manual flight approach)]
18:47:56.9
HOT-2 what?
18:47:58.8
FWC three hundred.
18:47:59.3
HOT-1 inhibit the glide for me.
18:48:00.6
HOT-2 okay.
18:48:03.0
HOT-2 inhibit.
18:48:05.8
HOT-2 middle.
18:48:11.6
FWC two hundred.
18:48:14.9
HOT-2 one dot now. okay.
18:48:16.8
HOT-1 okay.
18:48:21.0
FWC twenty.
18:48:21.6
FWC retard.
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.
18:48:30.8
HOT-1 aaiii. [sigh]
18:48:33.3
HOT-1 look this.
18:48:34.4
HOT-2 decelerate, decelerate.
18:48:35.9
HOT-1 it can't, it can't.
18:48:40.0
HOT-1 oh my god..... oh my god.
18:48:42.7
HOT-2 go go go , turn turn turn turn.
18:48:44.6
HOT-2 turn turn to... no, turn turn.
18:48:45.5
CAM [sound of crushing noises]
18:48:49.7
CAM-? (oh no) [male voice]
18:48:50.0
CAM [pause in crushing noises]
18:48:50.6
CAM-? [sound of scream, female voice]
18:48:50.8
CAM [sound of crushing noise]
[end of recording]
18:48:51.4
End of transcript
By Michael Targett
TAM A320 7/17/07 Sao Paulo Brazil
Cockpit Voice Recorder – Transcript
Start of Transcript
18:18:24.4 (all times are local time) [start of recording]
18:18:24.5
PA-1 [captain makes speech to passengers]
18:18:53.4
CAM-? [sound of whistling]
18:20:25.0
CAM [sound of flight attendant door open request]
18:20:28.1
CAM-1 is ok?
18:20:29.7
CAM-3 [flight attendant says that everything in the cabin is OK, and then asks where will they be landing]
18:20:33.3
CAM-1 I have just informed.
18:20:34.7
CAM-3 I didn't hear - sorry - her talking.
18:20:37.7
CAM-1 but she heard, Congonhas.
18:20:39.3
CAM-3 is it Congonhas? It’s great, so. she might have heard. thank you.
18:43:04.3
HOT-1 remember, we only have one reverse.
18:43:06.9
HOT-2 yes... only the left.
18:43:24.0
HOT-1 glideslope, LOC blue... LOC star. [LOC star means an asterisk is displayed on the FMA, which means the loc capture]
18:43:26.6
HOT-2 checked.
18:43:27.1
HOT-1 autopilot one plus two.
18:43:29.4
HOT-1 flaps one.
18:43:30.7
HOT-2 speed checked.
18:43:36.7
HOT-1 clear status.
18:43:41.8
HOT-2 clear status.
18:43:43.8
HOT-2 clear.
18:43:48.2
RDO-2 going to intercept the localizer, TAM three zero five four.
18:43:52.2
APP TAM three zero five four, reduce speed for the approach... and call the tower on frequency one two seven point one five, good afternoon.
18:44:00.0
RDO-2 one two seven one five, over.
18:44:01.7
HOT-1 good afternoon.
18:44:06.4
HOT-1 flaps two.
18:44:08.1
CAM-2 speed checked.
18:44:20.0
HOT-2 flaps at two.
18:44:22.3
RDO-2 Sao Paulo tower, this is TAM three zero five four.
18:44:26.1
TWR TAM three zero five four, reduce minimum speed for approach, the wind is north with zero six. I will report when clear three five left.
18:44:33.4
RDO-2 good evening, reducing to the minimum possible [speed].
18:44:36.3
HOT-1
landing gear down.
18:44:37.7
HOT-2 landing gear down.
18:44:53.9
HOT-1 flaps three.
18:44:55.1
HOT-2 speed checked.
18:44:57.4
HOT-2 flaps three.
18:45:03.9
HOT-1 flap full.
18:45:05.7
CAM-2 speed checked, flaps full.
18:45:10.6
HOT-1 standby final checklist
18:45:12.0
HOT-2 standing by.
18:45:12.9
CAM-1 glide star, set missed approach altitude.
18:45:15.0
CAM-2 ALT * *.
18:45:21.0
CAM-2 six thousand feet.
18:45:44.0
CAM [sound of windshield wipers operating]
18:45:52.1
CH2 [sound of outer marker beacon heard on channel 2]
18:46:03.2
HOT-1 final checklist.
18:46:04.6
HOT-2 final checklist, passing DIADEMA [name of the outer marker beacon]
18:46:10.4
PA-2 cabin crew, clear to land. [prepare for landing]
18:46:14.0
CAM-2 cabin crew.
18:46:15.2
CAM-1 advised.
18:46:16.0
CAM-2 auto thrust.
18:46:17.8
CAM-1 speed.
18:46:20.0
CAM-2 * *.
18:46:21.1
CAM-1 landing no blue.
18:46:22.6
CAM-1 ECAM MEMO [Electronic Centralized Aircraft Monitor - check memo status]
18:46:23.8
HOT-1 landing, no blue.
18:46:24.9
HOT-2 landing no blue.
18:46:26.1
HOT-1 okay?
18:46:26.7
HOT-2 okay... what?
18:46:28.6
HOT-2 okay.
18:46:30.8
HOT-? *.
18:46:30.8
HOT-2 final checklist complete.
18:46:33.8
CAM-1 runway in sight, landing.
18:46:41.7
CAM-1 ask him [the tower] about the rain condition, the runway condition, and if the runway is slippery.
18:46:57.0
RDO-2 TAM on final approach, two miles away. could you confirm conditions?
18:47:01.7
TWR it's wet, and it is slippery. I will report three five left clear, three zero five four.
18:47:06.1
RDO-2 already on final.
18:47:07.5
TWR the aircraft is starting the departure.
18:47:10.7
HOT-1 wet and slippery!
18:47:22.0
HOT-2 the aircraft is starting the takeoff run.
18:47:34.3
TWR TAM three zero five four, three five left, clear to land, the runway is wet, and is slippery and the wind is three three zero at eight. knots.
18:47:40.6
HOT-2 three three zero at eight, is the wind.
18:47:42.9
HOT-1 checked.
18:47:43.9
TWR three zero five four?
18:47:45.3
RDO-2 three zero five four, roger.
18:47:46.4
FWC four hundred.
18:47:49.8
HOT-1 is the landing clear?
18:47:50.7
HOT-2 clear to land.
18:47:52.3
HOT-1 land green, manual flight.
18:47:53.7
CAM [sound of autopilot disconnect tone]
18:47:54.1
HOT-2 checked.
18:47:54.8
HOT-1 inhibit the glide [GPWS aural warning] for me please.
18:47:55.7
CAM [sound of triple click indicating reversion from CAT II or III to CAT I approach mode (manual flight approach)]
18:47:56.9
HOT-2 what?
18:47:58.8
FWC three hundred.
18:47:59.3
HOT-1 inhibit the glide for me.
18:48:00.6
HOT-2 okay.
18:48:03.0
HOT-2 inhibit.
18:48:05.8
HOT-2 middle.
18:48:11.6
FWC two hundred.
18:48:14.9
HOT-2 one dot now. okay.
18:48:16.8
HOT-1 okay.
18:48:21.0
FWC twenty.
18:48:21.6
FWC retard.
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.
18:48:30.8
HOT-1 aaiii. [sigh]
18:48:33.3
HOT-1 look this.
18:48:34.4
HOT-2 decelerate, decelerate.
18:48:35.9
HOT-1 it can't, it can't.
18:48:40.0
HOT-1 oh my god..... oh my god.
18:48:42.7
HOT-2 go go go , turn turn turn turn.
18:48:44.6
HOT-2 turn turn to... no, turn turn.
18:48:45.5
CAM [sound of crushing noises]
18:48:49.7
CAM-? (oh no) [male voice]
18:48:50.0
CAM [pause in crushing noises]
18:48:50.6
CAM-? [sound of scream, female voice]
18:48:50.8
CAM [sound of crushing noise]
[end of recording]
18:48:51.4
End of transcript
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Groiund Spoiler Extension Speed
As anyone can easily verify from a host of online video clips, ground spoilers are extended swiftly on a A320.
This Video on Flightlevel350.com shows all three uses of the spoilers. Speedbrakes at the beginning (only seen extended and during retraction, very slowly), roll-function (only very slight deflections, but visible, especially during final approach), and ground spoilers. GS extension takes about 2 seconds.
This Video on Flightlevel350.com shows all three uses of the spoilers. Speedbrakes at the beginning (only seen extended and during retraction, very slowly), roll-function (only very slight deflections, but visible, especially during final approach), and ground spoilers. GS extension takes about 2 seconds.
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Following this thread with all its diversions from the erudite to the banal and especially to the hopelessly biased has been quite an education. However, if there is one positive that can be extracted from any accident it is precisely that: that the analysis and discussion will make us all better educated and more wary of the conditions that brought our colleagues to grief.
Unfortunately, one of the predominant themes of this thread on the part of some has been the attempt to cast immediate judgment and blame on the non-moving aspect of the Airbus thrust levers without even the slightest evidence that they played a causal role in the accident. If the latest information here quoting the Airbus AIT is accurate, then though the apparent failure of the PF to retard the TL2 to idle is the initiating factor for the accident, the fact of whether the TL's move a la Boeing or remain fixed as per Airbus is irrelevant. Retard only one of them in either case and on the other TL you will end up with a fixed thrust equivalent to the power setting of the engine at the time the first TL was retarded. It seems logical and it is logical, and it is most definitely not a case of the *computers* taking over and over-riding the pilot's intentions. In fact it's totally the opposite, with the *computers* doing all that's possible to match the thrust to the pilot's inputs (TL1 to idle, idle you get on #1, TL2 not moved, ok no change on #2 until you command it).
This logic also makes sense in terms of the ground spoiler actuation and autobrake application. The thrust levers are the pilot's primary tool to communicate his intentions to these systems both on a Boeing and on an Airbus. When a pilot leaves one TL at approach thrust and retards the other to idle the intention becomes entirely ambiguous ... does he want to land or is he preparing to go around? The *computers* cannot read minds and any arbitration on their part absent a clear signal of intention has a significant potential to be catastrophic. So, the resulting logic has to be: where the intention of the pilot cannot be determined because he has provided directly contradictory inputs, the system will remain in its current condition (spoilers and autobrakes armed) until other signals from the pilot (via TL's, Rev, manual braking or manual speedbrake) clearly indicate his intentions.
And really, this is the way that we pilots want it to be. Almost all of the high vitriol here is about how it must be the pilot who controls the aircraft and not the computer. In this event it seems the aircraft gave the pilot everything he commanded through his actions (REV on #1, approach power on #2, later manual brakes when applied), the problem was that those initial actions were not sufficiently unambiguous for the system to deduce that a landing was intended and that automatic ground spoiler and braking should occur, as opposed to requiring further manual inputs from the pilot to make that happen.
On the apparently confusing subject of whether the ground spoilers would have deployed had the speedbrake lever been extend, I believe the explanation is as follows: Per the FCOMs for the aircraft I have flown Ground Spoilers are only ever automatically actuated through the arming conditions and thrust lever positions as documented in earlier posts. Speedbrakes (or Flight Spoilers if you prefer) are another matter. These, which are physically the same control surfaces (3 of 5 anyway), can be actuated manually through the extension of the Speedbrake lever. On the A320's I flew this function was inhibited in CONF FULL (but that was 10 years ago). However, more recently flying A330s and A340s for several operators I have discovered that different aircraft of the same model have different inhibitions in this regard. It depends on the particular modification status of the aircraft which in this case is dictated by the flight control computer standard (for the A320, the SEC) installed. Quite likely all A320's are not the same in this respect either and hence the differing opinions from pilots flying models with different SEC standards installed.
Regardless of this though, the potential or not to manually extend the ground spoilers or speedbrakes is only relevant if an attempt to manually extend them actually occurred and failed to do so. So far there is no indication that this is the case. And, while on the subject of the ground spoilers, their effect on stopping distance is significantly less (though certainly still valuable) than it has been made out to be by some posters. In the TransAsia accident report regarding the over-run at Taipei Sungshan airport on page 91 it is noted that:
This can be confirmed by reference to MEL 27-92-02 which describes means for calculating takeoff and landing distances with the Ground Spoiler Control System inoperative. If we accept PJ2's calculations from post #120 of braking distance with Max manual braking and with Autoland and medium autobrake (ALD between 4100'-5400') as being reasonably accurate then the lack of ground spoilers would only have added 600'-800' to the actual landing distance. A noticable amount to be sure, but not at all the critical factor in this instance. As an aside, I'd hope that this would put paid to the idea of holding off on reverse or executing a go-around if the ground spoilers fail to deploy. For them to become the critical factor in stopping safely other failures or contaminant performance degradation would also have to occur at the same time.
In terms of the facts so far revealed (at least if we take the AIT information to be correct) there has been remarkably little discussion about the factor that stands out to me as being most directly responsible for the failure to bring the aircraft to a stop on the runway:
The failure to apply full manual braking as soon as a lack of normal deceleration was detected.
If the time of 11 seconds from touchdown to initial manual braking is accurate, this represents 2200'-2500' of the runway from the touchdown point that was traversed without either crew member taking an affirmative action to stop the aircraft. This delay seems to have occurred despite the fact that both crew members were aware in advance of the very limited stopping distance and the runway conditions and became aware within 3-4 seconds of touchdown that the spoilers had not extended. Why an extra 7 seconds passed before an attempt to do something about the lack of normal deceleration was made has to be the real crux of the investigation.
Reviewing the TransAsia accident, the same factor, a 15 second delay from touchdown to the first application of manual braking is also found to be a critical factor in the cause of that over-run. In fact, it is very instructive to note the Airbus performance calculations on page 143 of the report. There are too many variables to make a direct comparison to TAM 3054 (TNA had a lower weight but a higher ground speed), but it is worth noting that Airbus calculated the ground stopping distance on a wet runway with 1 engine in max reverse, 1 maintaining 1.08 EPR and no ground spoiler extension as being 1907m (about 6200') if braking equivalent to autobrake medium was used. With maximum manual braking that figure might be as much as 25% less, which leaves open the possibility that even without the crew ever recognizing that TL2 had not been retard and that the ground spoilers had not extended, the TAM aircraft might have still stopped on the runway or within the confines of the airfield if maximum manual braking had been applied at the first recognition of a failure in deceleration (18:48:29.5 HOT-2 "Spoilers Nothing").
All of this leads back around to whether there's a procedure in place for this that could have been identified and used in this circumstance. There is, and it is one of the very few required memory items for an A320:
Loss of Braking
If Autobrake is Selected:
Brake .....................Pedals Press
If No Braking Available:
Rev........................Max
Brake Pedals............Release
A/Skid & NW/STRG ...Off
Max Brk Press .........1000 PSI
If Still No Braking:
Parking Brake ..........Use
One might argue about whether the "Rev......Max" is best placed before "If No Braking Available" or after, but the essential point is that this procedure is the manufacturer's intended guidance on what to do at any time when the rate of braking experienced doesn't match the rate expected or the rate necessary to stop on the runway. And the first step is obvious, instinctive and requires no particularly arcane knowledge of flight control systems or spoiler and autobrake activation logic.
So, at the end of the day, though the question "Why did the crew member retard only 1 TL?" is a very important one, the really critical question to be answered, in this as in many other runway over-runs, is "Why did the crew allow so much time to elapse and so much runway to go by before attempting to brake manually?" More particularly, why was this so when they were completely aware of the runway length, runway surface condition and thrust reverser inoperative limitations?
To my eyes there are critical underlying training issues here that are far more relevant than any discussion about preventing this accident in future with things such as moving, vibrating thrust levers or planned go-arounds in the event that ground spoilers fail to extend.
ELAC
Unfortunately, one of the predominant themes of this thread on the part of some has been the attempt to cast immediate judgment and blame on the non-moving aspect of the Airbus thrust levers without even the slightest evidence that they played a causal role in the accident. If the latest information here quoting the Airbus AIT is accurate, then though the apparent failure of the PF to retard the TL2 to idle is the initiating factor for the accident, the fact of whether the TL's move a la Boeing or remain fixed as per Airbus is irrelevant. Retard only one of them in either case and on the other TL you will end up with a fixed thrust equivalent to the power setting of the engine at the time the first TL was retarded. It seems logical and it is logical, and it is most definitely not a case of the *computers* taking over and over-riding the pilot's intentions. In fact it's totally the opposite, with the *computers* doing all that's possible to match the thrust to the pilot's inputs (TL1 to idle, idle you get on #1, TL2 not moved, ok no change on #2 until you command it).
This logic also makes sense in terms of the ground spoiler actuation and autobrake application. The thrust levers are the pilot's primary tool to communicate his intentions to these systems both on a Boeing and on an Airbus. When a pilot leaves one TL at approach thrust and retards the other to idle the intention becomes entirely ambiguous ... does he want to land or is he preparing to go around? The *computers* cannot read minds and any arbitration on their part absent a clear signal of intention has a significant potential to be catastrophic. So, the resulting logic has to be: where the intention of the pilot cannot be determined because he has provided directly contradictory inputs, the system will remain in its current condition (spoilers and autobrakes armed) until other signals from the pilot (via TL's, Rev, manual braking or manual speedbrake) clearly indicate his intentions.
And really, this is the way that we pilots want it to be. Almost all of the high vitriol here is about how it must be the pilot who controls the aircraft and not the computer. In this event it seems the aircraft gave the pilot everything he commanded through his actions (REV on #1, approach power on #2, later manual brakes when applied), the problem was that those initial actions were not sufficiently unambiguous for the system to deduce that a landing was intended and that automatic ground spoiler and braking should occur, as opposed to requiring further manual inputs from the pilot to make that happen.
On the apparently confusing subject of whether the ground spoilers would have deployed had the speedbrake lever been extend, I believe the explanation is as follows: Per the FCOMs for the aircraft I have flown Ground Spoilers are only ever automatically actuated through the arming conditions and thrust lever positions as documented in earlier posts. Speedbrakes (or Flight Spoilers if you prefer) are another matter. These, which are physically the same control surfaces (3 of 5 anyway), can be actuated manually through the extension of the Speedbrake lever. On the A320's I flew this function was inhibited in CONF FULL (but that was 10 years ago). However, more recently flying A330s and A340s for several operators I have discovered that different aircraft of the same model have different inhibitions in this regard. It depends on the particular modification status of the aircraft which in this case is dictated by the flight control computer standard (for the A320, the SEC) installed. Quite likely all A320's are not the same in this respect either and hence the differing opinions from pilots flying models with different SEC standards installed.
Regardless of this though, the potential or not to manually extend the ground spoilers or speedbrakes is only relevant if an attempt to manually extend them actually occurred and failed to do so. So far there is no indication that this is the case. And, while on the subject of the ground spoilers, their effect on stopping distance is significantly less (though certainly still valuable) than it has been made out to be by some posters. In the TransAsia accident report regarding the over-run at Taipei Sungshan airport on page 91 it is noted that:
The Landing Performance in Sec. 1-27 “Flight Controls” of TransAsia’s A320 Minimum Equipment is states that if the ground spoilers are not extended, the landing distance of his type of aircraft (A320-232 B22310) shall increase by 15%.
In terms of the facts so far revealed (at least if we take the AIT information to be correct) there has been remarkably little discussion about the factor that stands out to me as being most directly responsible for the failure to bring the aircraft to a stop on the runway:
The failure to apply full manual braking as soon as a lack of normal deceleration was detected.
If the time of 11 seconds from touchdown to initial manual braking is accurate, this represents 2200'-2500' of the runway from the touchdown point that was traversed without either crew member taking an affirmative action to stop the aircraft. This delay seems to have occurred despite the fact that both crew members were aware in advance of the very limited stopping distance and the runway conditions and became aware within 3-4 seconds of touchdown that the spoilers had not extended. Why an extra 7 seconds passed before an attempt to do something about the lack of normal deceleration was made has to be the real crux of the investigation.
Reviewing the TransAsia accident, the same factor, a 15 second delay from touchdown to the first application of manual braking is also found to be a critical factor in the cause of that over-run. In fact, it is very instructive to note the Airbus performance calculations on page 143 of the report. There are too many variables to make a direct comparison to TAM 3054 (TNA had a lower weight but a higher ground speed), but it is worth noting that Airbus calculated the ground stopping distance on a wet runway with 1 engine in max reverse, 1 maintaining 1.08 EPR and no ground spoiler extension as being 1907m (about 6200') if braking equivalent to autobrake medium was used. With maximum manual braking that figure might be as much as 25% less, which leaves open the possibility that even without the crew ever recognizing that TL2 had not been retard and that the ground spoilers had not extended, the TAM aircraft might have still stopped on the runway or within the confines of the airfield if maximum manual braking had been applied at the first recognition of a failure in deceleration (18:48:29.5 HOT-2 "Spoilers Nothing").
All of this leads back around to whether there's a procedure in place for this that could have been identified and used in this circumstance. There is, and it is one of the very few required memory items for an A320:
Loss of Braking
If Autobrake is Selected:
Brake .....................Pedals Press
If No Braking Available:
Rev........................Max
Brake Pedals............Release
A/Skid & NW/STRG ...Off
Max Brk Press .........1000 PSI
If Still No Braking:
Parking Brake ..........Use
One might argue about whether the "Rev......Max" is best placed before "If No Braking Available" or after, but the essential point is that this procedure is the manufacturer's intended guidance on what to do at any time when the rate of braking experienced doesn't match the rate expected or the rate necessary to stop on the runway. And the first step is obvious, instinctive and requires no particularly arcane knowledge of flight control systems or spoiler and autobrake activation logic.
So, at the end of the day, though the question "Why did the crew member retard only 1 TL?" is a very important one, the really critical question to be answered, in this as in many other runway over-runs, is "Why did the crew allow so much time to elapse and so much runway to go by before attempting to brake manually?" More particularly, why was this so when they were completely aware of the runway length, runway surface condition and thrust reverser inoperative limitations?
To my eyes there are critical underlying training issues here that are far more relevant than any discussion about preventing this accident in future with things such as moving, vibrating thrust levers or planned go-arounds in the event that ground spoilers fail to extend.
ELAC
Last edited by ELAC; 4th Aug 2007 at 20:28.
Paxing All Over The World
Just to mention Pullup hard that a link to the full transcript was posted in #882 but you may not have read all of the thread.
The Landing Performance in Sec. 1-27 “Flight Controls” of TransAsia’s A320 Minimum Equipment is states that if the ground spoilers are not extended, the landing distance of his type of aircraft (A320-232 B22310) shall increase by 15%.
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It's a percentage. Per the MEL it would apply equally to distances calculated on wet or dry runways. In the TransAsia accident Airbus provided calculations for an exhaustive variety of combinations of thrust, braking, spoiler deployment and runway condition. All the numbers can be found in the accident report.
ELAC
PS - The specific value (e.g. 1.15) seems to vary a bit depending on mod status. For a previous carrier's A330's I found numbers of 1.15, 1.18 and 1.2 applying to different aircraft in the fleet.
ELAC
PS - The specific value (e.g. 1.15) seems to vary a bit depending on mod status. For a previous carrier's A330's I found numbers of 1.15, 1.18 and 1.2 applying to different aircraft in the fleet.
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My compliments, ELAC, on a very well thought out post.
Just to expand slightly on the Loss of Braking drill - well you did invite argument - it is in three sections, each beginning with the word "If", so if you have not used Autobrake, or are taxying, you begin at "If no braking available". It is then entirely logical for this to be followed by "Rev...Max" as the first item. If when using Autobrake the action "Pedals Press" cures the lack of braking you do not need to go any further, although on the day you may decide to.
TP
Just to expand slightly on the Loss of Braking drill - well you did invite argument - it is in three sections, each beginning with the word "If", so if you have not used Autobrake, or are taxying, you begin at "If no braking available". It is then entirely logical for this to be followed by "Rev...Max" as the first item. If when using Autobrake the action "Pedals Press" cures the lack of braking you do not need to go any further, although on the day you may decide to.
TP
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excellent post ELAC
excellent posting ELAC and a new angle to look into. Why so much time elapsed before using full manual braking.
small correction though. Taipei Sungshan airport is where the A320 overrun took place, not "Taipei Tainan" airport. TAinan airport is in South Taiwan. TAipei airport is in North TAiwan.
TAipei = TransAsia A320 overrun 10.18.04
Tainan = TransAsia A321 rolls over a truck on the landing rollout 3.21.03
Important not to confuse the two very different accidents. (you didnt, but others might)
small correction though. Taipei Sungshan airport is where the A320 overrun took place, not "Taipei Tainan" airport. TAinan airport is in South Taiwan. TAipei airport is in North TAiwan.
TAipei = TransAsia A320 overrun 10.18.04
Tainan = TransAsia A321 rolls over a truck on the landing rollout 3.21.03
Important not to confuse the two very different accidents. (you didnt, but others might)