AF 447 Thread No. 5
Join Date: Aug 2009
Location: Germany
Age: 67
Posts: 1,777
Likes: 0
Received 0 Likes
on
0 Posts
Hi,
It was just to emphasize that all this discussion about confuse push or pull or the inverse (choice yours) is useless ... as we know (for 99,9999999 % sure) that is not this possible type of error involved in this crash ...
Maybe no "good sens" .. but certainly "humor sens" .
Some seem's to had lost this particular sens
or the skill to detect it
jcjeant,
I haven't been impressed by your earlier posts, but this one takes the biscuit.....
Quite apart from the fact that everything indicates so far that the attitude displays were functional.
"Weird and wonderful" remarks such as yours only "pollute" the discussions.
I haven't been impressed by your earlier posts, but this one takes the biscuit.....
Quite apart from the fact that everything indicates so far that the attitude displays were functional.
"Weird and wonderful" remarks such as yours only "pollute" the discussions.
Maybe no "good sens" .. but certainly "humor sens" .
Some seem's to had lost this particular sens
or the skill to detect it
Join Date: Oct 2005
Location: 45 yards from a tropical beach
Posts: 1,103
Likes: 0
Received 0 Likes
on
0 Posts
Bearfoil
Your input on this subject has been prodigious, however, on your last, I have to disagree. They did very little 'by the book.' Inter alia:
On seeing the UAS prompt, the SOP is to set the pitch attitude to 5 degrees nose up, then consult the QRH for the appropriate pitch and N1 settings for weight and Flight Level. Why the much larger pitch-up and subsequent climb, with its associated loss of energy?
Had they recognised that the aircraft was stalled, the PF should have maintained nose down input on the sidestick, augmented by manual pitch trim.
There was at least one simultaneous sidestick input, which gives the algebraic sum of both inputs, and is completely forbidden. The correct procedure is to announce "I have control" and take control by pressing and holding the red pushbutton on the sidestick.
This is the most perplexing accident I can recall. There seems to have been much confusion over what information was being presented to the crew, versus what was reliable. Let us hope for more answers with the next BEA release.
Your input on this subject has been prodigious, however, on your last, I have to disagree. They did very little 'by the book.' Inter alia:
On seeing the UAS prompt, the SOP is to set the pitch attitude to 5 degrees nose up, then consult the QRH for the appropriate pitch and N1 settings for weight and Flight Level. Why the much larger pitch-up and subsequent climb, with its associated loss of energy?
Had they recognised that the aircraft was stalled, the PF should have maintained nose down input on the sidestick, augmented by manual pitch trim.
There was at least one simultaneous sidestick input, which gives the algebraic sum of both inputs, and is completely forbidden. The correct procedure is to announce "I have control" and take control by pressing and holding the red pushbutton on the sidestick.
This is the most perplexing accident I can recall. There seems to have been much confusion over what information was being presented to the crew, versus what was reliable. Let us hope for more answers with the next BEA release.
airtrens:
Given that the flight was being counducted in Night, IMC conditions at high altitude, in the clouds ... if they were looking out the window that would be an airmanship problem far more serious that if ice were hitting the windshield. That said, the most likely theory seems to be, at that temp and altitude, ice crystals forming, not ice hitting the aircraft in the form of sleet or hail. From the data so far.
Infrequent:
Agreed. Easy to lose it, particularly if they were in turbulent air. (Won't digress into how one could finesse a partial panel sort of scan using only heading ... that way lies madness!
)
bear:
As Nigel pointed ou, perhaps everything except the pitch and power thing for UAS ... if more CVR info becomes available, we may see how far into that procedure they got/went.
Nigel:
If I remember, this was in the end game, when someone took the controls, perhaps to overcome a losing situation. (Possibly they pushed buttons as the conversation of “your controls” took place.)
Wasn't this about when one pilot said they were hitting ten thousand feet ... absent more CVR info, we don't know all of the communication about controls. The second interim shows me that there was a verbal component to the last (and ultimately futile
) passing of controls.
An additional perception factor was the angle of the ice crystals - likely present - hitting the windshield. Where they in an angle giving the perception that the A/C is nose down?
Infrequent:
Without attitude indication at night in IMC, I don't think they would have have kept wings anywhere near level.
Agreed. Easy to lose it, particularly if they were in turbulent air. (Won't digress into how one could finesse a partial panel sort of scan using only heading ... that way lies madness!
)bear:
Some possibilities show these guys did everything by the Book. Even the procedure at the STALL Warning. Both of them.
As Nigel pointed ou, perhaps everything except the pitch and power thing for UAS ... if more CVR info becomes available, we may see how far into that procedure they got/went.
Nigel:
There was at least one simultaneous sidestick input, which gives the algebraic sum of both inputs, and is completely forbidden. The correct procedure is to announce "I have control" and take control by pressing and holding the red pushbutton on the sidestick.
If I remember, this was in the end game, when someone took the controls, perhaps to overcome a losing situation. (Possibly they pushed buttons as the conversation of “your controls” took place.)
Wasn't this about when one pilot said they were hitting ten thousand feet ... absent more CVR info, we don't know all of the communication about controls. The second interim shows me that there was a verbal component to the last (and ultimately futile
) passing of controls.
Last edited by Lonewolf_50; 27th Jul 2011 at 21:23.
Guest
Posts: n/a
Neptunus
"On seeing the UAS prompt......." The first input was NU, are you saying that was not an attempt to "SET PITCH" (at 5 degrees)?
"Why the much larger (larger than 5 degrees) PITCH UP?" Beats me, you are saying the "larger PITCH UP" was PF commanded? Not known.
"At STALL, the PF should have maintained ND". Not at all. He is trained to prevent loss of altitude. Cannot do that with maintained ND. The STALL warning is not STALL, something he has never experienced in this a/c.
"augmented by manual nose down trim". NO. They were not in the correct LAW to have been prompted: "Use Manual Trim Only".
"At least one simultaneous side stick input, which is forbidden" You are saying they were not attempting to maximize ss input to be certain they were at maximum deflection (authority)?
Without CVR (further) we cannot eliminate that this dual input was not sussed as a possible remedy for PITCH authority? That it was discussed, and attempted in spite of (horrors) it was forbidden?
"On seeing the UAS prompt......." The first input was NU, are you saying that was not an attempt to "SET PITCH" (at 5 degrees)?
"Why the much larger (larger than 5 degrees) PITCH UP?" Beats me, you are saying the "larger PITCH UP" was PF commanded? Not known.
"At STALL, the PF should have maintained ND". Not at all. He is trained to prevent loss of altitude. Cannot do that with maintained ND. The STALL warning is not STALL, something he has never experienced in this a/c.
"augmented by manual nose down trim". NO. They were not in the correct LAW to have been prompted: "Use Manual Trim Only".
"At least one simultaneous side stick input, which is forbidden" You are saying they were not attempting to maximize ss input to be certain they were at maximum deflection (authority)?
Without CVR (further) we cannot eliminate that this dual input was not sussed as a possible remedy for PITCH authority? That it was discussed, and attempted in spite of (horrors) it was forbidden?
Join Date: May 2011
Location: here
Posts: 131
Likes: 0
Received 0 Likes
on
0 Posts
"On seeing the UAS prompt......." The first input was NU, are you saying that was not an attempt to "SET PITCH" (at 5 degrees)?
"At STALL, the PF should have maintained ND". Not at all. He is trained to prevent loss of altitude. Cannot do that with maintained ND. The STALL warning is not STALL, something he has never experienced in this a/c.
"augmented by manual nose down trim". NO. They were not in the correct LAW to have been prompted: "Use Manual Trim Only".
Guest
Posts: n/a
Zorin
The first input was nose up. You are certain the a/c was not pointed down at this point? A NU input would be an attempt to level, if the a/c was PITCHED NOSE LOW. You also do not know the decision was not made that the safe conduct of the flight was in jeopardy?
This also ennables a further explanation of what occurred next, a lag in a/c response to the NU.
(at STALL)
"PITCH reduction to 5 degrees" . PF may have reduced his back pressure, but been unsuccessful at reducing PITCH. The a/c at STALL WARNING was at 6 degrees PITCH UP, so holding altitude at that attitude would be read by the Computer as a "stick back". Remember, up to this point, He WAS holding NOSE DOWN inputs. (Until STALL WARN).
Lastly "Why trim for NOSE DOWN when inputting NOSE UP"? He was NOT necessarily inputting NOSE UP, he may have been attempting a hold on to the altitude.
Also, he was not looking for TRIM, he was looking for AUTHORITY. He did not know the THS was full UP, and that he desperately needed to move it DOWN.
This is a gripe of mine. At unusual Attitudes (sic), why is the THS allowed to (commanded to?) migrate into a position where, if setting is unknown, it may be causing the problem PF is trying to solve?
The first input was nose up. You are certain the a/c was not pointed down at this point? A NU input would be an attempt to level, if the a/c was PITCHED NOSE LOW. You also do not know the decision was not made that the safe conduct of the flight was in jeopardy?
This also ennables a further explanation of what occurred next, a lag in a/c response to the NU.
(at STALL)
"PITCH reduction to 5 degrees" . PF may have reduced his back pressure, but been unsuccessful at reducing PITCH. The a/c at STALL WARNING was at 6 degrees PITCH UP, so holding altitude at that attitude would be read by the Computer as a "stick back". Remember, up to this point, He WAS holding NOSE DOWN inputs. (Until STALL WARN).
Lastly "Why trim for NOSE DOWN when inputting NOSE UP"? He was NOT necessarily inputting NOSE UP, he may have been attempting a hold on to the altitude.
Also, he was not looking for TRIM, he was looking for AUTHORITY. He did not know the THS was full UP, and that he desperately needed to move it DOWN.
This is a gripe of mine. At unusual Attitudes (sic), why is the THS allowed to (commanded to?) migrate into a position where, if setting is unknown, it may be causing the problem PF is trying to solve?
Neptunus Rex;
We'll soon know more about the pitch-up. I don't think a ND pitch attitude is plausible but given the loss of data there may be a possibility of a small indicated height loss to which the PF may have then responded - we just don't know yet.
However, I don't think any pitch-up is indicated in the memorized items under these conditions, (level cruise flight, aircraft not at risk). Loss of airspeed information is not an emergency nor is the safe conduct of flight impacted so one would go to the next main memory item, "Level off for troubleshooting". As I have said from the start, the first response is to "do nothing" (except ensure the aircraft is under control, then get the QRH out, then communicate with ATC/FA's etc), because both speed and thrust were fine just before the event and, within controllable variations (using attitude information and setting thrust to what it was before the AT disconnected),
From the First BEA Interim Report:
From an A330 flight crew training manual, (2007):
Because the displayed information may be erroneous, the flying accuracy cannot be assumed. Incorrect transponder altitude reporting could cause confusion. Therefore, a MAYDAY should be declared to advise ATC and other aircraft of the situation.
PART 1: MEMORY ITEMS
If the safe conduct of the flight is affected, the flight crew applies the memory items. They allow "safe flight conditions" to be rapidly established in all flight phases (takeoff, climb, cruise) and aircraft configurations (weight and slats/flaps).The memory items apply more particularly when a failure appears just after takeoff. Once the target pitch attitude and thrust values have been stabilized, as soon as above safe altitude, the flight crew will enter the 2nd part of the QRH procedure, to level off the aircraft and perform trouble shooting. This should not be delayed, since using the memory item parameters for a prolonged period may lead to speed limit exceedance.
PART 2: TROUBLE SHOOTING AND ISOLATION
GENERAL
If the wrong speed or altitude information does not affect the safe conduct of the flight, the crew will not apply the memory items, and will directly enter the part2 of the QRH procedure.
Depending of the cause of the failure, the altitude indication may also be unreliable. There are however, a number of correct indications available to the crew. GPS altitude and ground speed are available on MCDU GPS monitor page and RA may be used at low level.
For faulty ADR(s) identification, the flight crew may, either level off and stabilize the flight using the dedicated table in PART 2, or, if for instance already stabilized in climb, use the CLIMB table given in part 3. The trouble shooting will be more accurate, using the level off table.
LEVEL OFF AND STABILIZATION (IF REQUIRED)
The table gives the proper pitch and thrust values for stabilization in level off according to weight, configuration and altitude.
It must be noticed that, if the altitude information is unreliable, FPV and V/S are also affected. In this case, the GPS altitude, if available, is the only means to confirm when the aircraft is maintaining a level. When reliable, the FPV should be used.
If the memory items have been maintained for a significant period of time, the current speed may be quite above the target
If FPV is reliable, or if GPS altitude information is available:
--Maintain level flight (FPV on the horizon or constant GPS altitude)
--Adjust thrust according to the table
--Observe the resulting pitch attitude, and compare it with the recommended table pitch target.
• If the aircraft pitch to maintain level flight is above the table pitch target, the aircraft is slow, then increase thrust
• If the aircraft pitch to maintain level flight is below the table pitch target, the aircraft is fast, then decrease thrust
When the pitch required to maintain level off gets close to the table pitch target, re-adjust thrust according to table thrust target.
This technique permits to stabilize the speed quickly, without inducing altitude changes. If FPV is not reliable and GPS altitude information is not available (no means to ensure level flight):
Adjust pitch and thrust according to table, and wait for speed stabilization. Expect a significant stabilization time and important altitude variations.
On seeing the UAS prompt, the SOP is to set the pitch attitude to 5 degrees nose up, then consult the QRH for the appropriate pitch and N1 settings for weight and Flight Level.
However, I don't think any pitch-up is indicated in the memorized items under these conditions, (level cruise flight, aircraft not at risk). Loss of airspeed information is not an emergency nor is the safe conduct of flight impacted so one would go to the next main memory item, "Level off for troubleshooting". As I have said from the start, the first response is to "do nothing" (except ensure the aircraft is under control, then get the QRH out, then communicate with ATC/FA's etc), because both speed and thrust were fine just before the event and, within controllable variations (using attitude information and setting thrust to what it was before the AT disconnected),
From the First BEA Interim Report:
From an A330 flight crew training manual, (2007):
Because the displayed information may be erroneous, the flying accuracy cannot be assumed. Incorrect transponder altitude reporting could cause confusion. Therefore, a MAYDAY should be declared to advise ATC and other aircraft of the situation.
PART 1: MEMORY ITEMS
If the safe conduct of the flight is affected, the flight crew applies the memory items. They allow "safe flight conditions" to be rapidly established in all flight phases (takeoff, climb, cruise) and aircraft configurations (weight and slats/flaps).The memory items apply more particularly when a failure appears just after takeoff. Once the target pitch attitude and thrust values have been stabilized, as soon as above safe altitude, the flight crew will enter the 2nd part of the QRH procedure, to level off the aircraft and perform trouble shooting. This should not be delayed, since using the memory item parameters for a prolonged period may lead to speed limit exceedance.
PART 2: TROUBLE SHOOTING AND ISOLATION
GENERAL
If the wrong speed or altitude information does not affect the safe conduct of the flight, the crew will not apply the memory items, and will directly enter the part2 of the QRH procedure.
Depending of the cause of the failure, the altitude indication may also be unreliable. There are however, a number of correct indications available to the crew. GPS altitude and ground speed are available on MCDU GPS monitor page and RA may be used at low level.
For faulty ADR(s) identification, the flight crew may, either level off and stabilize the flight using the dedicated table in PART 2, or, if for instance already stabilized in climb, use the CLIMB table given in part 3. The trouble shooting will be more accurate, using the level off table.
LEVEL OFF AND STABILIZATION (IF REQUIRED)
The table gives the proper pitch and thrust values for stabilization in level off according to weight, configuration and altitude.
It must be noticed that, if the altitude information is unreliable, FPV and V/S are also affected. In this case, the GPS altitude, if available, is the only means to confirm when the aircraft is maintaining a level. When reliable, the FPV should be used.
If the memory items have been maintained for a significant period of time, the current speed may be quite above the target
If FPV is reliable, or if GPS altitude information is available:
--Maintain level flight (FPV on the horizon or constant GPS altitude)
--Adjust thrust according to the table
--Observe the resulting pitch attitude, and compare it with the recommended table pitch target.
• If the aircraft pitch to maintain level flight is above the table pitch target, the aircraft is slow, then increase thrust
• If the aircraft pitch to maintain level flight is below the table pitch target, the aircraft is fast, then decrease thrust
When the pitch required to maintain level off gets close to the table pitch target, re-adjust thrust according to table thrust target.
This technique permits to stabilize the speed quickly, without inducing altitude changes. If FPV is not reliable and GPS altitude information is not available (no means to ensure level flight):
Adjust pitch and thrust according to table, and wait for speed stabilization. Expect a significant stabilization time and important altitude variations.
... he was not looking for TRIM, he was looking for AUTHORITY. He did not know the THS was full UP, and that he desperately needed to move it DOWN.
At unusual Attitudes (sic), why is the THS allowed to (commanded to?) migrate into a position where, if setting is unknown, it may be causing the problem PF is trying to solve?
The unusual attitudes (UA) law looks to be a form of graceful degradation that is intended to ensure that automatic (robot) inputs no longer contradict a pilot trying to recover from an unusual attitude. (Note, current hints suggest this law state was not active in 447). Mikelour posted a few pages back on some UA scenarios he used to teach in the sim, some of which demonstrated that you needed to remember to get that trim wheel working to get the plane back under your control. (He also caveats that he wasn't sure if it was a "simism" or not).
The design thus (it seem to me) includes the possibility that a haywire robot may contribute to UA. If those out of normal parameters boundaries are reached, robot is told "sit on yer hands, you naughty boy" and the pilot flies as manually as can be in this aircraft, to include trimming the nose with his trim wheel -- he has to, as the robot has been put into the penalty box for a two minute minor. Don't know if there is a flag or alert for UA law that lets the crew know "robot is in the penalty box, you are flying a man down" or not.
I'll hope that Svarin, if he'd like, can pursue further his concerns on unexpected logic failures or failure modes.
Can't wait for the Friday report. Hopefully some of the fog will be burned off.
Join Date: Jan 2008
Location: uk
Posts: 857
Likes: 0
Received 0 Likes
on
0 Posts
It seems approach to stall training (and possibly all stall training) has become "lose altitude and fail check", leading to NU inputs, resulting in stall.
I suspect we will add 447 to the list of crashes quoted by the boeing guy. At least the problem has been recognised and will hopefully now get fixed.
[I'm still interested in what caused the initial climb into the stall though - like Bear says, the seconds either side of A/P disconnect are the key].
Guest
Posts: n/a
While I'm waiting for Zorin, I'd like to suggest a possible (sic) explanation for what we know.
I trust the Pilots were doing all they could. I trust they were highly qualified. I trust them easily as much or more than I do an a/c whose bread and butter is autoflight, and not UAS.
After the STALL, and what I take to be a proper and trained PF response, we find that the THS is 'held' in almost maximum NU. For this, the Pilot holds NU, well after his 'recovery' from STALL WARNING. What on Earth causes a Horizontal Stabiliser to be planted almost to the stops NUP, and in a STALL, with an extreme r/o/d?
Let alone a Pilot with full back stick? As I mentioned above, my opinion is NU stick is what gave the PF the best ND response.
Pardon? There is no other explanation except 'He didn't know about the Stall'. What else could this attitude be? Nose in the sky, tail first descent in average 10k fpm? No other attitude explains the basic environment, Panel or NO, Viz or NO, QRH or NO.
ACARS be damned, the trickle of 'data' from BEA aside, I think I know what explains this, if not the climb.
Also the "Duet" on ss at 10k.
I trust the Pilots were doing all they could. I trust they were highly qualified. I trust them easily as much or more than I do an a/c whose bread and butter is autoflight, and not UAS.
After the STALL, and what I take to be a proper and trained PF response, we find that the THS is 'held' in almost maximum NU. For this, the Pilot holds NU, well after his 'recovery' from STALL WARNING. What on Earth causes a Horizontal Stabiliser to be planted almost to the stops NUP, and in a STALL, with an extreme r/o/d?
Let alone a Pilot with full back stick? As I mentioned above, my opinion is NU stick is what gave the PF the best ND response.
Pardon? There is no other explanation except 'He didn't know about the Stall'. What else could this attitude be? Nose in the sky, tail first descent in average 10k fpm? No other attitude explains the basic environment, Panel or NO, Viz or NO, QRH or NO.
ACARS be damned, the trickle of 'data' from BEA aside, I think I know what explains this, if not the climb.
Also the "Duet" on ss at 10k.
Join Date: Oct 2005
Location: 45 yards from a tropical beach
Posts: 1,103
Likes: 0
Received 0 Likes
on
0 Posts
Bearfoil
No. There could have been significant, and changing, vertical currents affecting the flight.
Same answer as above.
Direct Law will display the Manual Pitch Trim prompt, because that is all that is available. They were in Alternate Law, so both automatic and manual pitch trim were available. Manual pitch trim has priority, and is faster. The system follows up and reverts to automatic when manual is relinquished.
The CVR should tell us the answer. However, the commanded inputs were predominantly nose up, which is anomalous, to say the least.
Not so. At "Approach to Stall" the training was to prevent loss of altitude. At "Stall" the technique is to lower the pitch attitude and accept a loss of altitude. Most A330 flights take place in Normal Law, where α Floor will prevent the stall. α Floor is only available in Normal Law, and is triggered when full back stick causes the pitch angle to reach α Prot.
[/QUOTE]
Captain Moody (nor anyone else) had never experienced volcanic ash causing all four engines on his B747 to flame out. Captin Sully had never experienced a double engine failure on his A320 at low level; nor had he previous experience of ditching a jet transport. Captain de Crespigny had never experienced an uncontained engine failure causing power loss, substantial airframe damage as well as collateral damage to multiple systems on his A380. Every once in a while, valiant members of our profession become involuntary test pilots. Mercifully, it is very rarely: thankfully, most of them rise to the occasion and become our heroes.
"On seeing the UAS prompt......." The first input was NU, are you saying that was not an attempt to "SET PITCH" (at 5 degrees)?
"Why the much larger (larger than 5 degrees) PITCH UP?" Beats me, you are saying the "larger PITCH UP" was PF commanded? Not known.
"augmented by manual nose down trim". NO. They were not in the correct LAW to have been prompted: "Use Manual Trim Only".
"At least one simultaneous side stick input, which is forbidden" You are saying they were not attempting to maximize ss input to be certain they were at maximum deflection (authority)?
"At STALL, the PF should have maintained ND". Not at all. He is trained to prevent loss of altitude. Cannot do that with maintained ND. The STALL warning is not STALL, something he has never experienced in this a/c.
[quote]...something he has never experienced in this a/c.
Captain Moody (nor anyone else) had never experienced volcanic ash causing all four engines on his B747 to flame out. Captin Sully had never experienced a double engine failure on his A320 at low level; nor had he previous experience of ditching a jet transport. Captain de Crespigny had never experienced an uncontained engine failure causing power loss, substantial airframe damage as well as collateral damage to multiple systems on his A380. Every once in a while, valiant members of our profession become involuntary test pilots. Mercifully, it is very rarely: thankfully, most of them rise to the occasion and become our heroes.
Join Date: Jun 2009
Location: Paris
Posts: 691
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by henra
Originally Posted by takata
In case of (d), ECAM messages (FLR) are compiled into Current Flight Report (CFR) sent by ACARS when they are linked to the same fault (having the same ATA). The priority would simply be PROBE-PITOT fault over ADR fault during the correlation window.
In this case, ADR 1+2+3, being not displayed (no BUSS), it would nonetheless trigger three ECAMs:
- ADR 1+2
- ADR 1+3
- ADR 2+3
In this case, ADR 1+2+3, being not displayed (no BUSS), it would nonetheless trigger three ECAMs:
- ADR 1+2
- ADR 1+3
- ADR 2+3
This system is for maintenance, not investigation. What really matter is that, at arrival, the maintenance must look at the PITOTs and not waste its time for troubleshooting ADRs or the flight Computers which reported in fact this pitot's failure.
This particular "FLR" ACARS was sourced/correlated with:
- EFCS2 & EFCS1 = Electronic Flight Control System 1 & 2 = Flight Control Data Concentrator (FCDC) 1 & 2
- AFS = Auto Flight System = Fault Isolation and Detection System (FIDS).
Hence, during this minute, those systems could have reported other "FLR" with the same ATA that could have been compiled within this reported ACARS.
The CAS falling suddenly triggered two other CAS monitoring functions different from this ADR self-monitoring discussed here. Beside PROBE-PITOT ECAM, the other Flags and Warnings time stamped 0210 were correlated with this sudden fall of speed, whatever ADR (external) fault was or wasn't reported. The second class 2 "FLR" at 0210 (27-93-34) points at FCPC#2 (PRIM2) OR a connection between FCPC2 and ADR1; BEA correlated also the two Maintenance messages (FCDC1 & FCDC2) to this fault. Maybe we'll got more details from their last findings about system fault logic and cockpit ECAM.
Join Date: Jun 2009
Location: NNW of Antipodes
Age: 81
Posts: 1,330
Received 0 Likes
on
0 Posts
With the ongoing discussion over the what the crew may have heard, seen or felt in the stalled environment, I believe the following should be noted:-
The overall effect may have been perceived as a Vmo/Mmo event. That of course doesn't explain exactly how the aircraft was delivered into that situation in the first place.
Taking a step back from the UAS upset, it is worthwhile noting that the flight plan provided for a climb to FL370 at SALPU. The forecast OAT at FL350 between ORARO and TASIL was -46°C, but with their weight of 205 tonnes and high OAT, that higher level request wasn't made to ATLANTICO.
Add ITCZ to the bolded comments above, plus an OAT value probably warmer than forecast, and you have a receipe that should have "rung a few bells" - but it didn't.
In the AF447 Thread on 27 September 2009 I wrote, "Icing that took place was probably 'rapid' as opposed to 'gradual'".
Following the AP/ATHR disconnect, the aircraft entered a "zoom climb". The Stall Warning sounded briefly during the pitch up manuever and some ND inputs were made and attitude was reduced to 7°NU but the AoA was still rising and the SW sounded again. Further NU inputs prevented any normal stall recovery and once the CAS became less than 60KTS the SW stopped.
As I stated over 2000 posts ago, the software needs to be changed to sense both the CAS and AoA direction of change and the effect of NCD values to provide an unambiguous "STALLED!" warning on the PFDs. There should be no need for the "big red button" marked "SOS", because if there is, it is only a cover-up for lack of training and/or understanding by those charged with the safe flight of the aircraft and all those souls onboard.
Also posted many moons ago was a suggestion that once a UAS event at cruise altitude is detected, that the AP/ATHR combo continue in a NORMAL 2 LAW where pitot dynamic/static related inputs are replaced by IRU data and a pseudo CAS is provided to the AP. This will also cover the 300 foot static baro loss often noted in these events, and with due warning to the crew enable them to monitor the situation and oversee that NORMAL 1 LAW is resumed when ADRs are in agreement.
You can, "Lead a horse to water, but you can't ....... "
Notwithstanding, there may also be some underlying physiological related events which will no doubt surface in the Final Report.
- Once stalled the AoA was never less than 35° and finished at 61°
- Pitch attitude was 16°NU at stall and at end of flight, though occasionally less
- Aerodynamic flow was abnormal/turbulent
- Likelihood of rain/hail striking cockpit windows was low
- Buffet vibration generated around wings and engine pods complete with noise
The overall effect may have been perceived as a Vmo/Mmo event. That of course doesn't explain exactly how the aircraft was delivered into that situation in the first place.
Taking a step back from the UAS upset, it is worthwhile noting that the flight plan provided for a climb to FL370 at SALPU. The forecast OAT at FL350 between ORARO and TASIL was -46°C, but with their weight of 205 tonnes and high OAT, that higher level request wasn't made to ATLANTICO.
"the little bit of turbulence that you just saw
[…] we should find the same ahead […] we’re in the cloud layer unfortunately we can’t climb much
for the moment because the temperature is falling more slowly than forecast"
[…] we should find the same ahead […] we’re in the cloud layer unfortunately we can’t climb much
for the moment because the temperature is falling more slowly than forecast"
In the AF447 Thread on 27 September 2009 I wrote, "Icing that took place was probably 'rapid' as opposed to 'gradual'".
Following the AP/ATHR disconnect, the aircraft entered a "zoom climb". The Stall Warning sounded briefly during the pitch up manuever and some ND inputs were made and attitude was reduced to 7°NU but the AoA was still rising and the SW sounded again. Further NU inputs prevented any normal stall recovery and once the CAS became less than 60KTS the SW stopped.
As I stated over 2000 posts ago, the software needs to be changed to sense both the CAS and AoA direction of change and the effect of NCD values to provide an unambiguous "STALLED!" warning on the PFDs. There should be no need for the "big red button" marked "SOS", because if there is, it is only a cover-up for lack of training and/or understanding by those charged with the safe flight of the aircraft and all those souls onboard.
Also posted many moons ago was a suggestion that once a UAS event at cruise altitude is detected, that the AP/ATHR combo continue in a NORMAL 2 LAW where pitot dynamic/static related inputs are replaced by IRU data and a pseudo CAS is provided to the AP. This will also cover the 300 foot static baro loss often noted in these events, and with due warning to the crew enable them to monitor the situation and oversee that NORMAL 1 LAW is resumed when ADRs are in agreement.
You can, "Lead a horse to water, but you can't ....... "
Notwithstanding, there may also be some underlying physiological related events which will no doubt surface in the Final Report.
Last edited by mm43; 29th Jul 2011 at 10:08. Reason: added approx. THS position
Join Date: Aug 2005
Location: fl
Posts: 2,525
Likes: 0
Received 0 Likes
on
0 Posts
While we make our final comments before the interim report Friday the 5 degrees nose up and climb power will only work prestall. Once stalled and had a 61 degree angle of attack in the descent at 10,000 fpm descent rate they need at least 30 degrees nose down pitch to recover. The 5 degrees pitch up and climb power wasn't applied when it should before the stall and they went way above that causing a full stall. Hopefully they will tell us Friday how they did this.
Join Date: Jun 2009
Location: Paris
Posts: 691
Likes: 0
Received 0 Likes
on
0 Posts
Hi mm43,
I'll add also few additional notes for those who are following this discussion:
When the second stall warnings sounded, at 0210:51 (see mm43 graph):
- @ FL375, aircraft was NOT in "abnormal attitude": pitch (~7°), Alpha (6°) and roll (10/12°) were NOT excessive, airspeed (215 kt) was NOT totally lost.... and THS (3NU) was NOT at maximum (14NU)... and of course, the aircraft was NOT stalled.
Everything seriously wrong started at this point and during the following 10 seconds:
- TOGA was applied (NU limited effect);
- Sustained NU sidestick orders;
- Pitch increasing from 7 to 16°;
- Alpha increasing from 6 to 16°;
- another 500 ft were added, reaching FL380;
- Speed falling from 215 to 185 kt;
- THS starting moving UP, (but reaching 13°NU only one minute LATER = close to the end of mm43 graph)
- The aircraft stalled at the apogee.... while the STALL, STALL warnings sounded at least 40 seconds more during the stall.
Originally Posted by mm43
With the ongoing discussion over the what the crew may have heard, seen or felt in the stalled environment, I believe the following should be noted...
When the second stall warnings sounded, at 0210:51 (see mm43 graph):
- @ FL375, aircraft was NOT in "abnormal attitude": pitch (~7°), Alpha (6°) and roll (10/12°) were NOT excessive, airspeed (215 kt) was NOT totally lost.... and THS (3NU) was NOT at maximum (14NU)... and of course, the aircraft was NOT stalled.
Everything seriously wrong started at this point and during the following 10 seconds:
- TOGA was applied (NU limited effect);
- Sustained NU sidestick orders;
- Pitch increasing from 7 to 16°;
- Alpha increasing from 6 to 16°;
- another 500 ft were added, reaching FL380;
- Speed falling from 215 to 185 kt;
- THS starting moving UP, (but reaching 13°NU only one minute LATER = close to the end of mm43 graph)
- The aircraft stalled at the apogee.... while the STALL, STALL warnings sounded at least 40 seconds more during the stall.
Join Date: Oct 2005
Location: 45 yards from a tropical beach
Posts: 1,103
Likes: 0
Received 0 Likes
on
0 Posts
bubbers 44
Absolutely right. As I said, 5 degrees nose up pitch was the correct response to UAS. Once in the stall, corrective nose down pitch must be applied.
Let's see what Friday brings to help us understand this enigma.
Absolutely right. As I said, 5 degrees nose up pitch was the correct response to UAS. Once in the stall, corrective nose down pitch must be applied.
Let's see what Friday brings to help us understand this enigma.
Neptunus Rex;
According to the A330 flight crew training manual and the UAS drill, a 5° pitch up at cruise altitude is not the correct response to the UAS memory items. The correct response is to maintain level flight and troubleshoot.
PJ2
According to the A330 flight crew training manual and the UAS drill, a 5° pitch up at cruise altitude is not the correct response to the UAS memory items. The correct response is to maintain level flight and troubleshoot.
PJ2
Guest
Posts: n/a
Neptunus Rex
"5 degrees NOSE UP PITCH was the correct response". (To UAS).
Both Zorin and I disagree. Zorin claims it was "LEVEL OFF and troubleshoot". My claim is that with NOSE UP per PF, he could have been trying to do either five degrees NU OR LEVEL OFF, as the siituation demanded.
In Turbulent air (an accepted factor), AutoPilot could have trimmed NOSE DOWN to keep the a/c on altitude (UPDRAFT). We don't know yet the PITCH @ a/p drop. With UPDRAFT, the AoA is increased independent of SA, and depending on energy therein, the NOSE UP would have an additional bias NOSE UP, perhaps adding to the unexpectedly ambitious PITCH UP when the a/c responded?
"Once in the STALL, corrective NOSE DOWN PITCH must be applied."
PF had been applying NOSE DOWN PITCH. At 6 degrees NOSE UP, he heard the STALLSTALL, selected TOGA, and apparently, with back pressure, attempted an escape from the STALLWARNING, as he had been trained.
At this POINT, the STALL WARNING is important, in the sense that had it continued, it is likely the PF may not have sensed the NOSE FALLING, felt or heard buffet, or had other STALLED cues. We don't know except the BEA said the PITCH kept increasing. From here, BEA have no applicable statements except to say the PITCH did not decrease below 16 degrees.
There is no 'STALLED' prompt inSTALLED.
As before, I am offering possibilities to keep my mind open; if others have witheld judgment, so much the better.
regds
bear
"5 degrees NOSE UP PITCH was the correct response". (To UAS).
Both Zorin and I disagree. Zorin claims it was "LEVEL OFF and troubleshoot". My claim is that with NOSE UP per PF, he could have been trying to do either five degrees NU OR LEVEL OFF, as the siituation demanded.
In Turbulent air (an accepted factor), AutoPilot could have trimmed NOSE DOWN to keep the a/c on altitude (UPDRAFT). We don't know yet the PITCH @ a/p drop. With UPDRAFT, the AoA is increased independent of SA, and depending on energy therein, the NOSE UP would have an additional bias NOSE UP, perhaps adding to the unexpectedly ambitious PITCH UP when the a/c responded?
"Once in the STALL, corrective NOSE DOWN PITCH must be applied."
PF had been applying NOSE DOWN PITCH. At 6 degrees NOSE UP, he heard the STALLSTALL, selected TOGA, and apparently, with back pressure, attempted an escape from the STALLWARNING, as he had been trained.
At this POINT, the STALL WARNING is important, in the sense that had it continued, it is likely the PF may not have sensed the NOSE FALLING, felt or heard buffet, or had other STALLED cues. We don't know except the BEA said the PITCH kept increasing. From here, BEA have no applicable statements except to say the PITCH did not decrease below 16 degrees.
There is no 'STALLED' prompt inSTALLED.
As before, I am offering possibilities to keep my mind open; if others have witheld judgment, so much the better.
regds
bear
Join Date: Aug 2005
Location: fl
Posts: 2,525
Likes: 0
Received 0 Likes
on
0 Posts
I'm waiting patiently. If all it takes is UAS training to keep this from happening again then do the UAS training so even the automatic airplanes can be flown with automation inop with a qualified pilot. I never flew one that the throttles didn't move and you just monitored so feel fortunate.
My J3's and Twin Beeches, Lears, biplanes and Boeings didn't have much of that magic stuff. Had autoland at the end but never did one outside the sim.
I prefer yokes and sticks because you can see what everybody is doing and it feels really good when you hit a bump and if your hand moves an inch or two you are still stable. You don't have to worry about potentiometers and all that electronic magic.
My J3's and Twin Beeches, Lears, biplanes and Boeings didn't have much of that magic stuff. Had autoland at the end but never did one outside the sim.
I prefer yokes and sticks because you can see what everybody is doing and it feels really good when you hit a bump and if your hand moves an inch or two you are still stable. You don't have to worry about potentiometers and all that electronic magic.
Join Date: Oct 2007
Location: France
Posts: 136
Likes: 0
Received 0 Likes
on
0 Posts
Some news?
On a reconstitué l'accident de l'AF447 au simulateur - Le Point
Had they accessed some leaks, or pure journalist assumption?
The time data are strange: Publié le 27/07/2011 à 23:59 - Modifié le 27/07/2011 à 21:15 (French time: UTC+2).
Is it credible one can hear ice coming out Pitots bouncing on cockpit? ("Dans le cockpit, s'ajoute le bruit de la glace se détachant des sondes.": ~ In the cockpit, you have to add the noise of the ice coming apart from Pitots)?
On a reconstitué l'accident de l'AF447 au simulateur - Le Point
Had they accessed some leaks, or pure journalist assumption?
The time data are strange: Publié le 27/07/2011 à 23:59 - Modifié le 27/07/2011 à 21:15 (French time: UTC+2).
Is it credible one can hear ice coming out Pitots bouncing on cockpit? ("Dans le cockpit, s'ajoute le bruit de la glace se détachant des sondes.": ~ In the cockpit, you have to add the noise of the ice coming apart from Pitots)?
Last edited by Shadoko; 28th Jul 2011 at 02:42.