Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

AF 447 Thread No. 5

Tech Log The very best in practical technical discussion on the web

AF 447 Thread No. 5

Old 28th Jul 2011, 03:45
  #801 (permalink)  
 
Join Date: Jul 2011
Location: Northern Hemisphere
Posts: 195
Likes: 0
Received 0 Likes on 0 Posts
Hello Shadoko,

Thanks for posting.

The article shows a simulation aligned very much with the BEA report we already know well - no new, surprise elements. Which perhaps is an indirect indication of what's coming on Friday....

Turbulence is at a level, where the PNF needs to keep his pointer on the lines of the check-lists he is reading.


Originally Posted by Shadoko
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)?

Last edited by airtren; 28th Jul 2011 at 13:04.
airtren is offline  
Old 28th Jul 2011, 04:24
  #802 (permalink)  
 
Join Date: Jan 2005
Location: W of 30W
Posts: 1,916
Likes: 0
Received 0 Likes on 0 Posts
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,
The FCTM you quote must be an Airline's customized version ... ?
If so, that Airline did a very good job by stating things clearly, which Airbus has not done yet.
For Airbus, as quoted earlier by A33Zab, the correct procedure is to take initially 5 degrees NU + CLB thrust :
The initial pitch attitude and thrust values given in the QRH should be considered as "Memory Items", since they allow "safe flight conditions" to be rapidly established in all flight phases (takeoff, climb, cruise) and aircraft configurations (Weight and slat/flaps).
CONF iture is offline  
Old 28th Jul 2011, 05:10
  #803 (permalink)  
 
Join Date: Jan 2005
Location: W of 30W
Posts: 1,916
Likes: 0
Received 0 Likes on 0 Posts
As the messenger for Airbus or BEA as you wish, Le Point a parlé :
  • L'action du PF à cabrer sur le manche continue, et aura été majoritaire pendant 95 % des quatre minutes.
  • Les données contenues dans les enregistreurs de vol montrent très précisément comment s'est déroulé le crash de l'AF447, et permettent d'identifier les conséquences de l'action à cabrer du PF.

Originally Posted by bubbers44
I prefer yokes and sticks because you can see what everybody is doing
Amen !

Do we have to consider both the PNF could not see what the PF was doing ...
CONF iture is offline  
Old 28th Jul 2011, 05:34
  #804 (permalink)  
 
Join Date: Oct 2009
Location: berlin
Posts: 152
Likes: 0
Received 0 Likes on 0 Posts
mm43 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.
THX for the THS position in your analysis. at which time did they passed SALUP?

the climb to F370 (without trust correcting) has finished 02:10:40
the following correctionTOGA was also not corrected in his pitchup momentum....

and then a stray purring cat was laying on the stick.......
grity is offline  
Old 28th Jul 2011, 06:03
  #805 (permalink)  
PJ2
 
Join Date: Mar 2003
Location: BC
Age: 76
Posts: 2,486
Received 2 Likes on 2 Posts
CONF iture;

Thanks for responding.

I don't want to put too fine a point on this as it is just one of a number of notions which have been put forward to come to terms with the pitch-up. The drill and checklist are a problem.

The very fact that there is primary disagreement about how to do this checklist is itself, interesting and revealing.

I do see your point of course, but think about it: What pilot is going to pitch an A330 up at 5 degrees at FL350, expecting that the aircraft is not going to climb? The pitch and power settings for an A332 at FL350 at 205T for 260kts is 3.5deg and 70.9% N1. Five degrees is not going to be a runaway climb but it is going to climb.

The early drills and checklist, (2002, 2003) do indeed state that the "Immediate Pitch Attitude and Thrust Guidance" above FL100 is 5deg of pitch and CLB thrust.

The drill and checklist in force at the time of the accident is confusing because it's flow is not clear nor are the priorities for the pilot. I have made the points before that there are several "bifurcations" in the checklist which are difficult and problemmatic to memorize. The FCTM statements, (2007) which I reference state quite clearly that if the flight is not in immediate danger, then the procedure is to level off and troubleshoot.

The rest of the statement which you quoted from A33Zab's original posting reads as follows, (my bolding in the first sentence and after):

"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."

Regardless of what Friday's release has to say, this drill and checklist is a problem.
PJ2 is offline  
Old 28th Jul 2011, 06:10
  #806 (permalink)  
 
Join Date: May 2011
Location: here
Posts: 131
Likes: 0
Received 0 Likes on 0 Posts
bear,

sorry, us humans need to sleep from time to time.
To cut it short, no, of course I don't know what happened. Still we can assign different levels of probability to the various suggested scenarios. I'm absolutely with you in firmly believing they were trying to do what from their perspective looked like the best chance to get home.
Zorin_75 is offline  
Old 28th Jul 2011, 10:41
  #807 (permalink)  
 
Join Date: Jun 2009
Location: VA, USA
Age: 58
Posts: 578
Received 0 Likes on 0 Posts
Audible ice shedding from pitots? Nope...

Sadoko:
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)?
As one who spends his life creating sound simulations for all classes of aircraft (at the highest fidelity Level D for commercial aircraft and equivalently for military sims), I find it almost impossible to believe that anyone could believe such ice shedding would be audible - the location of the pitot tubes themselves and, above all else, the small quantity of ice involved (due to the physical size of the tube) makes this claim extremely unlikely.

As it stands, for the many simulators I have been involved in, ice shedding from propellers, with the ice being flung from the blades and hitting the cabin sides, is about the only sound cue related to icing that I believe might be audible to any cockpit crew.

Given the altitude, true airspeed and the factors mentioned above, I do not believe that ice leaving the pitot tubes would cause any noticeable audible cue for the crew AT ALL.
GarageYears is offline  
Old 28th Jul 2011, 12:45
  #808 (permalink)  
 
Join Date: Jun 2009
Location: Paris
Posts: 691
Likes: 0
Received 0 Likes on 0 Posts
Hi Neptunus Rex,
post #791
I'm sharing all your comments, only one tid bit should be added.
Originally Posted by Neptunus Rex
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.
α Floor is only available in Normal Law, but it is inhibited above Mach 0.53. Below this speed, high AOA protection would reduce pitch while applying α Floor. It is obvious that high AOA protected mode is aimed at low altitude, high pitch and low speed situations which are, by very far, what is frequently needed.

At first sight, stalling at cruise level seems so unlikely, in protected mode or not, that most of the documentation/procedure is not even talking about the case.

At cruise, if one hear the stall warnings, this FCOM sentence "release back pressure on the sidestick" is also inherently implying that the PF is pulling gee's during manoeuver, hence triggering SW, not that he is flying level at the onset for buffet.

If one look at the UAS/Turbulence penetration procedure tables, in clean configuration, safe pitch/thrust settings (=> Mach 0.80):
@ FL370, over 190 t:
- Pitch: 3°
- N1: 94.3%

Hence, at FL375, TOGA would not make that much difference as the aircraft would be very close to its maximum cielling anyway. Also, applying a 5° pitch "above FL100" is in reality aimed for above FL100 and below FL250. It is 3.5° from FL250 to FL370 (90% N1) and 3° above FL370. Also, those settings should be memory items for turbulence penetration speeds.

TOGA + pull up is the Windshear normal procedure. In no way it is related to STALL or UAS procedures at cruise altitude.

Also, while the situation was deteriorating seriously, from 0210:51, the aircraft took another 10 seconds to enter this full stall with all Alarms soundings. Even so, the PF still had its Flight Path Vector (FPV) working. In fact, it was flagged much later when alpha/speeds became again invalid when the stall was much more advanced.

This is another puzzling fact as the FPV (which seems to have been selected) would provide a visual increasing Alpha for the pilots. Moreover, during this early stall sequence, it is also probable that the Flight Directors came back on PFDs and that all speeds/baro altitude were valid and coherent again (but without any characteristic speeds -VLS, VSw, VMax- displayed).

Consequently, my opinion is that the PF should have distrusted all its instruments as everything seems to be working fine in the cockpit displays at this crucial point... but also, during the following 30-40 seconds, in addition to this Stall Alarm which never stopped its warnings.
takata is offline  
Old 28th Jul 2011, 13:31
  #809 (permalink)  
 
Join Date: Jul 2011
Location: Northern Hemisphere
Posts: 195
Likes: 0
Received 0 Likes on 0 Posts
Le Point article on AF 447 accident simulation

For those that are more comfortable with an English version, here are some excerpts from the article. I've selected based on elements discussed on the AF 447 threads:

- the thrust at FL 350 was at %85 - article comment: "at this altitude Thrust level changes other than Idle don't bring a very significant power variation."

- "for changing altitude, the procedure requires a pitch no less than 0 degrees for descent, or 4 degrees for ascent."

- "the altitude change caused a buzzer to sound at 200 ft above FL350."

- "95% of 4 minutes, the NU action was present. However, there were a total of 6 short ND commands."

- "at FL 375 the climb is at 700ft/min, and the plane still flies at 4 degrees attitude and 215knots, certainly slow"

- "when the Captain rejoins, the speeds are invalid, the Stall Warning stops, quite a confusion in the cockpit"

- "while the plane was at 10000ft/min descent, and 40 degree attitude (AoA), the actions of thrust to Idle, and ND don't bring a significant change, AoA remaining above 35 degrees."

Last edited by airtren; 28th Jul 2011 at 15:43.
airtren is offline  
Old 28th Jul 2011, 13:49
  #810 (permalink)  
 
Join Date: Jul 2011
Location: Northern Hemisphere
Posts: 195
Likes: 0
Received 0 Likes on 0 Posts
GarageYears,

It seems that they've created sounds for the simulation, that replicate the AF 447 cockpit surrounding recorded sounds. Do you doubt that as well?

The article's author interpretation of the "ice cracking" sound which you point to, may be very well wrong.

With your experience of generating sounds from difference sources, for simulation, what's your interpretation, what is that "ice cracking" sound coming from?

Originally Posted by GarageYears

As one who spends his life creating sound simulations for all classes of aircraft (sims), I find it almost impossible to believe that anyone could believe such ice shedding would be audible -....
airtren is offline  
Old 28th Jul 2011, 13:50
  #811 (permalink)  
bearfoil
Guest
 
Posts: n/a
Garage Years

Just the man for this. In the manual re: UAS one of the potential causes for loss of airspeeds is a shed radome. Whether 447 lost her fiber nose or not, would the radome contacting the fuselage area near the probes be audible to a crew?
 
Old 28th Jul 2011, 13:55
  #812 (permalink)  
 
Join Date: Jun 2009
Location: Paris
Posts: 691
Likes: 0
Received 0 Likes on 0 Posts
Hi airtren,
Originally Posted by airtren
Some excerpts from the article, which have elements discussed on the AF 447 threads:
This article seems to be a mix between BEA and Presslike-fantasy (simulation). What could be trully learned from it at one day from an official interim report release?
The only interesting information out the whole content is this one:
Originally Posted by Point
Retrouvez notre dossier "Rio-Paris, révélations sur une catastrophe", dans Le Point n° 2028, en kiosque dès jeudi.
They are just selling their "Rio-Paris dossier" in today paper issue, as tomorrow, it will be certainly outdated.
takata is offline  
Old 28th Jul 2011, 13:59
  #813 (permalink)  
 
Join Date: Jun 2011
Location: france
Posts: 760
Likes: 0
Received 0 Likes on 0 Posts
bea report one day before !

It appears that the french radio "FRANCE-INFO" (MM. FELDZER, POLACKO, aso) received not only the BEA report, but all informations from the both CVR and DFDR, when it is refused to public use !?
Are OACI procedures no more in use in FRANCE ?
roulishollandais is offline  
Old 28th Jul 2011, 14:06
  #814 (permalink)  
 
Join Date: Mar 2002
Location: Florida
Posts: 4,569
Likes: 0
Received 1 Like on 1 Post
I have seroius doubts about the interpretation that they heard ice cracking sounds on the CVR

Lots of CVR recording over the years and the only ice sounds documented to my knowledge have been impact sounds from hail hitting the frontal faces. The relative velocity of a shed off an aircraft surface pitot would be too low and this "Ice crack sounds" defies imagination. Even the ice sheds off the MD80 incidents could not be heard.
lomapaseo is offline  
Old 28th Jul 2011, 14:06
  #815 (permalink)  
 
Join Date: Jul 2002
Location: UK
Posts: 3,093
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by roulishollandais
It appears that the french radio "FRANCE-INFO" (MM. FELDZER, POLACKO, aso) received not only the BEA report, but all informations from the both CVR and DFDR, when it is refused to public use !?
Are OACI procedures no more in use in FRANCE ?
Really? The only thing up on their website is an interview with two of the people involved in the simulator reconstruction sessions - they don't say anything about having a leaked report...
DozyWannabe is offline  
Old 28th Jul 2011, 14:11
  #816 (permalink)  
bearfoil
Guest
 
Posts: n/a
takata

I have not been persuaded by the ICE theory. It is not at all unusual for a radome to come off the nose. After all, it bears mention in the FCOM.

Whether 447 lost her fiber/resin nose or not, the "Sound" in the CVR will be interesting.

I am keeping an open mind.

lomapaseo, your thoughts re: Radome loss?
 
Old 28th Jul 2011, 14:26
  #817 (permalink)  
 
Join Date: Jul 2011
Location: Northern Hemisphere
Posts: 195
Likes: 0
Received 0 Likes on 0 Posts
Hello PJ2,


Originally Posted by PJ2
... As I have said from the start, the first response is to "do nothing" (except ensure the aircraft is under control,...
Indeed, from the start, you've said this consistently, many times....Your confidence and calm which I wish in every pilot of an airplane I am a passenger of, make it sound very simple, very safe....

Would you consider qualifying a bit the very succinct "do nothing ... ensure the a/c is under control", in regards to the flight law, and turbulence?

Is there anything you would add, is there a need to differentiate the needed actions between the A/C being in "Normal Law, No Turbulence", "Alternate 2, and NO Turbulence", and "Normal Law, with 3 degrees of turbulence: mild, medium, heavy", and "Alternate 2 and mild, medium, heavy turbulence"?.
airtren is offline  
Old 28th Jul 2011, 14:29
  #818 (permalink)  
bearfoil
Guest
 
Posts: n/a
02:09:45~02:10:25 It's in here.
 
Old 28th Jul 2011, 14:36
  #819 (permalink)  
 
Join Date: Feb 2001
Location: right here inside my head
Age: 65
Posts: 178
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Bearfoil
it is not at all unusual for a radome to come off the nose.
I don't think that's an accurate statement at all Bear. I think it's extremely unusual. ...and extremely unlikely.
3holelover is offline  
Old 28th Jul 2011, 14:42
  #820 (permalink)  
 
Join Date: Jul 2011
Location: Northern Hemisphere
Posts: 195
Likes: 0
Received 0 Likes on 0 Posts
Hello Takata,

The picture is informative.

Would you have a clue, what training center is that?

Originally Posted by takata
Hi airtren,

This article seems to be a mix between BEA and Presslike-fantasy (simulation). What could be trully learned from it at one day from an official interim report release? .
airtren is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.