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 1st Aug 2011, 18:44
  #1261 (permalink)  
The Analog Kid
 
Join Date: Aug 2004
Location: Brecon Beacons National Park
Age: 57
Posts: 239
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Takata
Originally Posted by Saturn V
2 h 10 min 49
PNF: () il est o euh ?
1. the sentence is unfinished, "euh" at the end means that PFN missed the word and did not bother to complete it later.
2. "Where is it... uh..."
Whilst I don't necessarily disagree with the thrust of the rest of your post, I actually parsed this as:

"il est o, hein?"

They would sound very similar.

(Caveat: I am not a native speaker, but have been listening to French from an early age, as my father taught it, and was once fluent in it myself.)
fyrefli is offline  
Old 1st Aug 2011, 18:52
  #1262 (permalink)  
 
Join Date: Jun 2001
Location: US
Posts: 245
Likes: 0
Received 0 Likes on 0 Posts
2 h 11 min 06
PNF: () il vient ou pas

There's been some discussion as to whether "il" refers to the captain or the aircraft (Avion is masculine in French, so from a purely grammatical sense "il" could be l'avion.)

If you read the entire CVR transcript we have, there is no other reference to "il" referring to the aircraft. The three pilots usually say "je" ("I"), "tu" (second person singular "you"), or "on" (which here means "we", as in "on monte" -- "we're climbing"). That is, they always refer to either their own individual actions or to themselves collectively (which includes the aircraft, as they are in it). Nowhere else do they seem to refer to the aircraft as a distinct object. In my experience, this is common. You would say "il" refering to an airplane if you were outside it watching it; you would not usually say "il" if you were inside it.

"il vient" also would be a very unusual way to refer to an aircraft maneuver, unless one was at an airport waiting for the aircraft to arrive, for example. If it were "il monte" or "il descend" or "il se redresse" (he's recovering") or "il pique" (he's diving) it would make more sense, but I cannot think of any maneuver where a pilot would say "il vient".

So my conclusion is that "il" refers to the captain, and not the aircraft.
spagiola is offline  
Old 1st Aug 2011, 18:58
  #1263 (permalink)  
 
Join Date: Mar 2001
Location: us
Posts: 694
Likes: 0
Received 0 Likes on 0 Posts
takata and fyrefli and spagiola, thanks.

Perhaps with luck, a native English speaker will help with the English version of the third interim report, perhaps someone like the NTSB or AAIB representative / liaison to the BEA.
SaturnV is offline  
Old 1st Aug 2011, 19:17
  #1264 (permalink)  
 
Join Date: Jun 2009
Location: uk
Age: 62
Posts: 3
Likes: 0
Received 0 Likes on 0 Posts
I have now read many statements that the correct action should have been "pitch and power" at cruise level. If this is really true can any of the knowledgeable posters explain to me why autopilot disconnect was so urgent when speeds started to become strange. Could it not have continued on by simply keeping pitch and power with some noisy kind of alarm to the pilots.
I wondered more or less the same. Although I can perhaps understand the logic of the automation handing over with unreliable data and the desire not to complicate its logic still further, is it not possible to provide a simple emergency cruise "autopilot" that could be manually engaged in such circumstances that simply keeps the wings level and pitch at 5 degrees.
solaise is offline  
Old 1st Aug 2011, 19:28
  #1265 (permalink)  
 
Join Date: Aug 2009
Location: Texas
Age: 64
Posts: 6,553
Received 72 Likes on 45 Posts
Dozy, it read pilots to me. Perhaps me being far sighted and the PC I was using is to blame. If what you said was "apart from the pitots nothing was wrong" then my response to you was to something you didn't say.

Sorry about that. My, what a waste of bandwidth over that little error.

Apologies due to you and Old Carthusian for confusing the issue due to a slight reading problem.

takata:

Sorry, we are not speaking the same language nor in the same terms.

When the Captain leaves the flight deck, there are two pilots, one in each seat.

WHO IS IN CHARGE?

You can't answer that with "they are both co-pilots." There are expected roles for two pilots in a multi pilot cockpit.

So, when the Captain left, WHO WAS IN CHARGE?

The new rule, which was the end of your post, seems to be

Whomever is now sitting the left seat is in charge until I (the Captain) get back and relieve him.

Correct?

EDIT: to all of you kind folks, thanks for explaining the nuances of French in the reference that I presumed referred to the Captain's return, once called by the PNF. No hablo Francais sehr gut.

From something gums had said about how the F-16 waffles and falls in a particular kind of stall, it appears that the A330 has a similar "soft" feel to the stall ... but then, it appears that the nose was being held up, which kept it in a stall. Perhaps the "feeling" wasn't all that pronounced, other than the roll excursions early on, and so what the PNF was seeing and experiencing wasn't as obvious to the folks in the cabin, which included the Captain.

Last edited by Lonewolf_50; 1st Aug 2011 at 19:48.
Lonewolf_50 is offline  
Old 1st Aug 2011, 19:44
  #1266 (permalink)  
The Analog Kid
 
Join Date: Aug 2004
Location: Brecon Beacons National Park
Age: 57
Posts: 239
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Lonewolf_50
When the Captain leaves the flight deck, there are two pilots, one in each seat.

WHO IS IN CHARGE?
According to the procedures in operation at the time, the Junior F/O, as PF, in the RH seat.

Originally Posted by Lonewolf_50
The new rule, which was the end of your post, seems to be

Whomever is now sitting the left seat is in charge until I get back and relieve him.
That's also my understanding.
fyrefli is offline  
Old 1st Aug 2011, 19:49
  #1267 (permalink)  
 
Join Date: Jul 2011
Location: Northern Hemisphere
Posts: 195
Likes: 0
Received 0 Likes on 0 Posts
Christiaanj,

I think your post's contribution to the cause of the French language awareness of the non-francophone audience is welcome.

The common good is more important than the individual's so a thorough and thoughtful reading of my post which would have helped, if you're interested in avoiding making invalid assumptions, and saving time and bandwidth, of a preamble and unnecessary explanation of "l'avion" genre to me, is of a lesser importance.

Hm.... maybe a while back, your anglophone friends were also picking on, and/or having fun, to the use of a "feminine" name, to call a masculine object, resulting in the "le Concorde".... ... makes me think of the beautiful "Caravelle"...

Of course, I appreciate your honest reinforcing of the "il vient pas" translation, and agree with "ca viens ou pas? ...." regarding which, I would have been in agreement with Takata's take.... which is still bemusing me.

Originally Posted by ChristiaanJ
Sorry, airtren, but you obviously don't live in France.
You should have SOME doubts....
In French it's "un avion", so an aircraft is "il".
I've had regular problems explaining this to anglophone firends...
"Why do the French refer to a Concorde as "he" or "it", rather than "she" ?"

That said, you may have a valid point... "il vient ou pas" is more likely to refer to the captain than to the response of the aircraft. I would have expected "a vient ou pas ?" in the latter case (still too colloquial to translate unequivoqually without the full context)
Spagiola,

You pointed out some aspects that I have not thought about before, but now, when I think about them, switched to French language, make a lot of sense... thanks.

Originally Posted by spagiola
2 h 11 min 06
PNF: () il vient ou pas

There's been some discussion as to whether "il" refers to the captain or the aircraft (Avion is masculine in French, so from a purely grammatical sense "il" could be l'avion.)
...
So my conclusion is that "il" refers to the captain, and not the aircraft.

Last edited by airtren; 1st Aug 2011 at 21:33.
airtren is offline  
Old 1st Aug 2011, 20:19
  #1268 (permalink)  
 
Join Date: Jul 2007
Location: Virginia, USA
Age: 85
Posts: 77
Likes: 0
Received 0 Likes on 0 Posts
Lonewolf 50

I would think PNF would have been PIC in the Captain's absence. He had by far the greater total hours and hours in type, of the two, IIRC. Although, he had just come off "vacation"-- here another need to examine the French wording... off several weeks vacation, or was it that his mandated turn-around rest had been a little short of the required hours? Did I read correctly that PNF had just completed a [short?] rest in the rest cabin; did the Captain ask if he had gotten enough rest?

Again, PNF was sitting in the LH seat; ie, that otherwise occupied by the Captain. Now given the logistics of moving around in the cockpit this may have been just convenience of the moment. On the other hand, the A/C seems designed to be flown in emergency more conveniently from the LH seat.

Well, regardless of what one thinks of that, there can be not doubt that if you want to have some idea of what the pilot actually flying is seeing on his screens, datawise, then the pilot flying has to be sitting in the LH seat. Of course, we would still not know if the pilot actually flying was actually looking at the particular screen for which we would know the data.

But it does suggest to me there should be a policy that the PIC sit in the LH seat, and that the normal procedure in emergency should be for the PIC to request that control be turned over to him. (I do recognize that there are conditions when not making a change could be better, but this does not seem to have been such here.)

I agree we need to know French and AF custom in this regard, and indeed AB' thoughts on which side is better for control in emergency-- given AB did not treat each side the same. It would certainly be helpful for tenancy of the LH seat to indicate the chain of command, in cases such as this.

One other thought... This minature SS seems in this situation only to have the virtue of saving weight. Wasn't this control orginally devised for situations having many g's, where a pilot could at most only move his fingers? Certainly at 2 g's a skier can support his whole body, and easily move his arms about. --OE
Old Engineer is offline  
Old 1st Aug 2011, 20:52
  #1269 (permalink)  
 
Join Date: Feb 2001
Location: The Winchester
Posts: 6,476
Received 4 Likes on 4 Posts
Old Engineer

But it does suggest to me there should be a policy that the PIC sit in the LH seat, and that the normal procedure in emergency should be for the PIC to request that control be turned over to him
On the other hand in the case of augmented ops with the captain on break that would mean in any emergency automatically turning over control to the co-pilot sitting in the his/her "non natural seat", the Left one....which might not be the best idea ( the aircraft should be designed to be flown with equal "ease" from either seat, but a co-pilot's natural habitat is the Right Hand one)
wiggy is offline  
Old 1st Aug 2011, 21:05
  #1270 (permalink)  
 
Join Date: Jul 2011
Location: Northern Hemisphere
Posts: 195
Likes: 0
Received 0 Likes on 0 Posts
Takata,

Thanks for this answer. It seems the answer to the question posted by RetiredF4.

But will use the opportunity to ask a question of mine. But before I do that, if my sense of the tone of your post is correct, please take it as a very simple, non loaded question.

The range of air speeds was from 275knots down to very low values, which is quite a wide range.

Is one default value correct for such a wide range?

Originally Posted by takata;6612433; post 1253
Why do you think that system would bother to isolate any compromised ADR channel - they are continuously monitored in real time - beside for avoiding that wrong imputs would be used by the system flight controls?

Alternate law 2 is just doing that; C* law is modified; imputs are treated differently with less gain (meaning that default values are used instead of real air data).
If this part of your post is the answer to my question, then let me make sure!

My question was about "stick input duration", and there is no "duration" in your answer...

So, I will rephrase the question, just in case it was not clear, picking some numbers for the sake of clarity:

Is there a difference between the control surface deflection in response to a 1 second long stick input to a position 2/3 of stop, and the control surface deflection in response to one stick input that is 5 seconds long to the same position 2/3 of stop?

Originally Posted by Takata, post: 1253
There is no proportionality between surface deflection and stick imputs until direct law. Those imputs are translated into load-factor demand, and system will deliver them up to the limits (2.5g/-1 g in clean conf.).

Last edited by airtren; 1st Aug 2011 at 21:21.
airtren is offline  
Old 1st Aug 2011, 21:19
  #1271 (permalink)  
 
Join Date: Jul 2007
Location: Virginia, USA
Age: 85
Posts: 77
Likes: 0
Received 0 Likes on 0 Posts
Wiggy

Yes, that is a good point. Although it does appear that PNF was issuing instructions to PF which possibly were not being followed. But then, without the tone of the statements, what was being said exactly is a bit unclear, I'll grant. Then too, whether at the time of these comments the A/C had elevator authority to implement the ordered (if so) action is likewise unclear. --OE
Old Engineer is offline  
Old 1st Aug 2011, 21:27
  #1272 (permalink)  
 
Join Date: Jan 2005
Location: France
Posts: 2,315
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Old Engineer
Although, he had just come off "vacation"-- here another need to examine the French wording... off several weeks vacation, or was it that his mandated turn-around rest had been a little short of the required hours?
You're right, another language issue.... with the classic problem that similar English and French words do NOT necessarily mean the same...
The French word for holidays/vacation is "vacances".
"Vacation" in French refers to a "time on duty", so it's the opposite notion from the English.
Hope that helps.
ChristiaanJ is offline  
Old 1st Aug 2011, 21:41
  #1273 (permalink)  
 
Join Date: Jun 2009
Location: NNW of Antipodes
Age: 80
Posts: 1,330
Likes: 0
Received 0 Likes on 0 Posts
Originally posted by OE ...
I would think PNF would have been PIC in the Captain's absence. He had by far the greater total hours and hours in type, of the two, IIRC. Although, he had just come off "vacation"-- here another need to examine the French wording... off several weeks vacation, or was it that his mandated turn-around rest had been a little short of the required hours? Did I read correctly that PNF had just completed a [short?] rest in the rest cabin; did the Captain ask if he had gotten enough rest?
Interim Report No.1 refers to the crew as a "whole", and indicates that they flew out of Paris on the morning of 28 May 2009 (AF446?).

The passenger list provides the information that the Jnr F/O had his wife onboard. There is also a question mark regarding her possible presence on the FD.

There has been discussion a page or two back which suggested that the Capt actually appointed the PF (RHS) as his deputy before leaving the FD. Also, since the accident (takata reports) that AF policy has been changed and that the Snr F/O will sit in the LHS and assume command when the Capt is not on the FD. This action would tend to confirm that the Jnr F/O was both PF and PIC.
mm43 is offline  
Old 1st Aug 2011, 22:06
  #1274 (permalink)  
 
Join Date: Jul 2007
Location: Virginia, USA
Age: 85
Posts: 77
Likes: 0
Received 0 Likes on 0 Posts
mm43

Thanks for bringing me up to speed on the Captain's change-of-command instructions. I read his statement in the French, but this was one of those times when I relied on my own French, even though to me it was an ambiguous statement. My exact thought was, "Did he really say that, and what did he mean?" Well, I'm really short on French idiomatic usage and conversational French, and should have not skipped over some of the explanation from those trying to help. --OE
Old Engineer is offline  
Old 1st Aug 2011, 22:29
  #1275 (permalink)  
 
Join Date: Jun 2009
Location: florida
Age: 80
Posts: 1,583
Received 19 Likes on 5 Posts
back to the "technical" stuff

- First of all, and to A33Z, what's the document you are using for elevator deflection per "g"? And for the c.g. versus elevator moment arm? etc.

About 95% of the military FBW jets have the all-moving HS, and no "elevator". This is extremely important once past the mach, if not essential ( ask Yeager about his X-1 missions). So your document must be pointed at subsonic designs and heavies. And by the way, several subsonic designs have the all-moving HS/elevator.

As far as aircraft movement about the c.g......... where's the center of aero forces, the mean aero chord (MAC)? There are very good reasons to have the elevator at certain distances from both the c,g, and the MAC. Too close and the plane is 'twitchy", and too far makes the beast sluggish, and so forth.

I also question a minimum of 1 deg of elevator per gee. That seems very sensitive, and unless the control surface movement is biased by dynamic pressure, you can get into trouble real fast. I would prefer a surface deflection related to maximum movement AND maximum gee AND dynamic pressure, as we had in the Viper ( probably Shuttle, but have to ask some friends).

- Secondly. I'll beat the dead horse once again. Why doesn't the system have a "standby gains" to be used by HAL when the pitot system fails or is deemed unreliable. Our primitive FBW system had such, and it worked in just the situation AF447 encountered, and a prominent caution light came on.

"Standby gains" prevent the potential problem another poster has questioned - "what does HAL use for control surface "laws" when airspeed is unreliable or missing? maybe A33Z can answer that?

- Finally, I disagree that the plane was unrecoverable without using a horrendous 30 degree nose down attitude, or more. The 'bus appears to have excellent, if not oustanding directional capabilities, whether in a rudder "law" or basically good aero design. Our little jet took rudder away from us once AoA was above 29 -30 degrees to help avoid a spin. Hence, our deep stall was relatively free of yaw and had little uncommanded roll excursions.

Our problem was the pitch moment with the full nose down stabilizer, yet nose up capability was still there. Sound familiar?

The swept wing beasts don't have the sharp stall break that straight wing planes have. The usual problem at extreme AoA is that drag exceeds available thrust if you maintain the "back" stick pressure Concorde, all the delta designs, Vulcan, Shuttle, and the beat goes on. On all of those, you could get flying again without lowering the nose to a horrendous nose down attitude, while using all available power. I speak from personal experience from my hours in the Deuce long ago.

It seems that AF447 came close to "breaking the stall", i.e. getting thrust greater than drag. Using the full movement of the THS could have been the key.
gums is offline  
Old 1st Aug 2011, 22:37
  #1276 (permalink)  
PJ2
 
Join Date: Mar 2003
Location: BC
Age: 75
Posts: 2,482
Received 0 Likes on 0 Posts
HN39;
Originally Posted by Post #1200
That's another intriguing thing. The ADR's calculate Mach and CAS quasi-simultaneously from the same pitot and static pressures. Why would there be a delay of two seconds between Mach and CAS?
Yes, intriguing indeed. I doubt if it's "polling" in nature, as these values would be in continuous calculation, but "polling", (so to speak...it doesn't quite work that way, but close), does affect flight data due to recording rates-per-second. Between the two, I'm not sure what the ADR "saw". Is the two second apparent delay merely just that? ...the time it took for BITE processes to assess/decide and the first test was Mach No.?

We have only limited resources from which to build theories and create tentative conclusions; it has been my experience that one cannot rely upon the flight data, (meaning, one must take into account parameter recording rates), for these things because of polling rates, whereas, as you observe, Mach, CAS, etc are "quasi-simultaneously" calculated and (one assumes), sent to the "users", (the ADRs) for use.

Here, I'm not sure about the notion of "quasi-simultaneous" - are these calculations truly parallel and "held in memory" until all processes are finished and data can be sent onwards, or are they series and the data is sent as it becomes available, and if so, at what point in the calculation is a decision made, for example, if quasi-simultaneous calculations result in one Mach value of M0.26, does the process stop there and bifurcate into a "can the AFS remain engaged?" loop, or is it more recursive than this, "just to make sure" of data correctness and a decision to disengage is confirmed? From my reading of the AMM, it seems a lot simpler than this, and I wonder if the two-second "delay" is actually a delay or is it the nature of flight data itself?
PJ2 is offline  
Old 1st Aug 2011, 22:40
  #1277 (permalink)  
 
Join Date: Aug 2009
Location: Germany
Age: 67
Posts: 1,810
Likes: 0
Received 0 Likes on 0 Posts
Cool

Hi,

mm43
Interim Report No.1 refers to the crew as a "whole", and indicates that they flew out of Paris on the morning of 28 May 2009 (AF446?).
Thank you for this information
I miss it in my read of the report N1
So this make more weird to me the question of the captain to the Jnr F/O if he had the good qualifications for take the duty .... as reported in the report N3
So for the flight Paris - Rio ... the captain don't bothered of the qualifications .... or this Jnr F/O was never in charge .. for the Paris - Rio ?
jcjeant is offline  
Old 1st Aug 2011, 22:45
  #1278 (permalink)  
 
Join Date: Mar 2001
Location: us
Posts: 694
Likes: 0
Received 0 Likes on 0 Posts
The wife of the PF had gone with him to Brazil because the crew had a long layover in Brazil. As it was also Pentecost weekend, this meant a long holiday weekend. She taught physics in high school. Their two young sons remained in France.

The PF had the most flying hours of the three in the previous 30 days.

Hope that clarifies the circumstances of her trip, which I had mis-interpreted.
SaturnV is offline  
Old 1st Aug 2011, 23:13
  #1279 (permalink)  
bearfoil
Guest
 
Posts: n/a
As a Frernchman, jc, consider: Mrs. PF may be seated on the FD, in attendance, with her husband as PF. Perhaps a Plum for PF? Captain's question about the licensure was to reassure Captian as to legality? The seating arrangements and Ile de Sein recovery were reported amid mystery as to who sat where, and why the #4 was retrieved.

But......what would be the relevance anyway, if all was 'kosheur'?

Simply this. Ready to be corrected, but I am in a large family with strong representation of Native French. It is considered extremely RUDE to correct someone in his work. It is inexcusable to correct him in front of a woman, especially his wife.

Last edited by bearfoil; 1st Aug 2011 at 23:27.
 
Old 1st Aug 2011, 23:21
  #1280 (permalink)  
 
Join Date: Jul 2011
Location: South coast Geneva lake
Age: 82
Posts: 7
Likes: 0
Received 0 Likes on 0 Posts
to jcjeant [QUOTE] So for the flight Paris - Rio ... the captain don't bothered of the qualifications .... or this Jnr F/O was never in charge .. for the Paris - Rio ?

From interim report july 29

 Flying hours:
total: 2,936 on type: 807(9) in the previous six months: 368 hours, 16 landings, 18 take-offs in the previous three months: 191 hours, 7 landings, 8 take-offs in the previous thirty days: 61 hours, 1 landing, 2 take-offs
This pilot had performed five rotations in the South America sector since arriving in the A330/A340 division in 2008, including one to Rio de Janeiro. His oceanic route qualification was valid until 31 May 2010.
hulotte is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell or Share My Personal Information

Copyright © 2023 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.