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

AF 447 Search to resume

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

AF 447 Search to resume

Old 8th Apr 2011, 22:46
  #3201 (permalink)  
 
Join Date: Jun 2009
Location: NNW of Antipodes
Age: 78
Posts: 1,330
Originally posted by HazelNuts39 ...
It would be of interest to know the tolerance of the “credibility” test of the monitoring process internal to the TCAS which applies to the standard altitude parameter. It shouldn't be too difficult for the BEA to get that from the TCAS manufacturer.
It took until the Report #2 for relevance of that ACARS message to be interpreted, which supprises me, on the basis that it appears to have been a non documented routine.
mm43 is offline  
Old 8th Apr 2011, 23:21
  #3202 (permalink)  
 
Join Date: Jan 2005
Location: W of 30W
Posts: 1,939
Originally Posted by takata
One will also note that this aircraft used a different (faulty?) hardware and would remember that this issue was not an "upset" properly: in fact, even if this situation could have caused some serious harm to the passengers, it did not cause an "upset" as the aircraft did not departed from its safe flight envelope (which doesn't mean that this problem was not dangerous for the aircraft safety).
The point on QF72 is that that airplane decided to do something on its own and on which the crew had absolutely no control.

In this case, this would mean that they were not aware of the weather situation as they were not flying in "turbulence penetration mode", having their A/THR still ON up to this point.
Unless thrust changes become excessive, it is not an Airbus request to disconnect A/THR for turbulence.

Originally Posted by dvv
The NIST team has studied WTC7 quite thoroughly, and the study only confirms that the 9/11 conspiracy nuts are just that — conspiracy nuts.
'Thoroughly' until you read it.
I can only encourage people to read these guys too and evaluate if they qualify for the name of nuts ...
CONF iture is offline  
Old 8th Apr 2011, 23:38
  #3203 (permalink)  
 
Join Date: Jun 2009
Location: NNW of Antipodes
Age: 78
Posts: 1,330
Originally posted by ventus45 ...
... there was no "post separation impact" with any other part of the aircraft, nothing other that water, and even that must have been "benign".
Put it another way, "Why would there have not been any surface damage to the V/S if it had fluttered down from altitude?"

No, the benign landing in the water was IMHO a consequence of the fortuitous way that it parted company with the empennage at impact. A combination of a high CG and the noted fact that the tail was rotating to port at impact, allowed the V/S to depart and fall into clear water about 30 degrees to the left of the heading at impact. Its residual momentum probably allowed it then to drift clear of any other surface debris.
mm43 is offline  
Old 9th Apr 2011, 00:08
  #3204 (permalink)  
 
Join Date: Aug 2005
Location: fl
Posts: 2,561
Probably more that the wind had an influence on it's movement with the current so moved it downwind of the bodies because it floated in the wind effect. Sort of like if you let loose of your boat in the water and the wind blew it away from you and you couldn't outswim it.
bubbers44 is offline  
Old 9th Apr 2011, 00:47
  #3205 (permalink)  
 
Join Date: Jul 2007
Location: My Stringy Brane
Posts: 377
ventus45 -- We're still waiting to hear what specific in-flight forces would cause the separation of AF447's VS.

Why the similar condition to the VS of ANZ A320 that hit the sea near Perpignan at 260+ knots?
Machaca is offline  
Old 9th Apr 2011, 01:14
  #3206 (permalink)  
 
Join Date: Jun 2009
Location: Midpines, CA
Posts: 56
More info on the Ile de Sein ship.

ILE DE SEIN - 9247039 - Vessel's Details and Current Position


Automatic Identification System (
AIS) position and tracking.

Live Ships Map - AIS - Vessel Traffic and Positions


ACLS65 is offline  
Old 9th Apr 2011, 01:32
  #3207 (permalink)  
 
Join Date: Jun 2009
Location: Paris
Posts: 691
Originally Posted by CONF iture
The point on QF72 is that that airplane decided to do something on its own and on which the crew had absolutely no control.
On the other hand, the fact that such incident happened only twice in the very same aircraft, as well as during the same flight, and that hundreds of other A330 flew safely many millions hours without ever experiencing it would give all the statistical depth necessary to conclude that this incident was obviously related to this particular aircraft and/or flight.

Originally Posted by CONF iture
Unless thrust changes become excessive, it is not an Airbus request to disconnect A/THR for turbulence.
Unless I'm wrong, capitains are supposed to act like their Company is asking them to do by applying their Company published procedures.
Then, specific Air France procedure for A330 would ask for a speed reduced to M 0.80 and A/THR disconnected if an expected turbulence zone would be crossed. I don't think that they are different from Airbus ones in that respect.
Consequently, either this crew wasn't expecting any turbulence at all up to this point, either nobody was seriously looking at the weather radar.

Originally Posted by CONF iture
I can only encourage people to read these guys too and evaluate if they qualify for the name of nuts ...
There is plenty of books published about the sociology of the rumor spreadings. Maybe you should try to read one and avoid to make a fool of yourself.

There was three official and independant "commission d'enquête", all made in order to convince the people from Abbeville that the flooding of the Somme area in May-June 2001 was not decided by the governement in Paris for protecting the capital from being flooded (even if the bassin of the Seine can't be pumped and deversed into the Somme). Nonetheless, most people from Abbeville are still believing the later today.

Last edited by takata; 9th Apr 2011 at 01:52.
takata is offline  
Old 9th Apr 2011, 01:36
  #3208 (permalink)  
 
Join Date: Dec 2010
Location: Middle America
Age: 81
Posts: 1,163
Originally posted by CONF iture...
...Unless thrust changes become excessive, it is not an Airbus request to disconnect A/THR for turbulence.
At 35 and .82 in A/THR while entering an area of disturbed weather, would the pilot choose to manually ease back on thrust to slow speed on the basis to make the Pax more comfortable?

I ask this question in that having passed through the first storm cell and suddenly entering the second cell, which was much more formidable, if speed was bled off intentionally and that this might have been the prelude to events that followed?
Turbine D is offline  
Old 9th Apr 2011, 01:47
  #3209 (permalink)  
PJ2
 
Join Date: Mar 2003
Location: BC
Age: 73
Posts: 2,460
TurbineD;

Turbulence penetration speed is 260kts at FL350, M0.78 higher, which would normally be selected on the FCU [Flight Control Unit on the glareshield]. Manual thrust is often selected to avoid large thrust changes with airspeed variation. The A330/A340 ALT mode is a "soft" hold which permits about a 50' altitude variation above/below the target altitude. This is primarily for fuel conservation purposes but permitting minor variations in turbulence also works. seem to recall that the books say that maintaining attitude and allowing altitude variations in severe conditions is preferred. Sounds easy, doesn't it?

On the VS...
I'm a bit surprised that the present discussion regarding the VS is taking on the dimensions of the MLG-extended discussion. It has been discussed at length in the past. I think it can be assumed that both will be resolved in the next few months.

That said, for those who argued two years ago and continue to do so today that the VS came off in flight, the question remains regarding the relatively pristine condition of most of the cabin interior parts, and, as we know now, the undersea wreckage.

We know from past accidents that a complete loss of the VS, as in this case, will, without fail in a swept-wing aircraft, result in a loss-of-control, almost certainly, but not inevitably, followed by a high-speed impact.

Notwithstanding that qualification, there isn't a single case of a transport category aircraft surviving the loss of the entire vertical stabilizer.*

We now know that the wreckage is concentrated indicating an intact aircraft at impact, but by the few photographs seen in public, large sections of the aircraft have survived relatively intact meaning a low-forward-speed impact. Contrast this with the condition of the Swissair 111 MD11 remains, even after a LOC from between 5000 and 2000ft, (TSB Report, Sec 1.18.9.3, pg.196)**

The wreckage found on the surface, and now onsite, does not bear the earmarks of a high-forward-speed impact. I think a more reasonable conclusion is that the VS broke off at impact, ostensibly as mm43 describes above, (8th Apr 2011 16:38).


*I am fully aware of the photograph and survival of the Vietnam B52, which has been used to counter this example before. But some of the VS remains, enough, obviously to provide the lateral stability needed to make it home - I would be interested in an engineer's POV on this; the JapanAir B747 bulkhead accident remained aloft through extremely competent airmanship providing deft handling of power, but was eventually lost - the circumstances under which AF447 was operating would almost certainly preclude such a response.

**The TSB Report on SR111 is interesting reading for a number of reasons, some of which may possibly relate to a few aspects of AF447. Not thinking of a fire-on-board as a possibility but of comments regarding crew confusion from multiple warnings and system failures, and other aspects such as wreckage recovery, and investigation processes. Impact was 300kts, as explained in the report. The China Airlines B747-200 in-flight disintegration is also an interesting report to read in the light of both what is known and what may some expectations may be.

Last edited by Jetdriver; 9th Apr 2011 at 14:27.
PJ2 is offline  
Old 9th Apr 2011, 03:06
  #3210 (permalink)  
 
Join Date: Jun 2009
Location: I am where I am and that's all where I am.
Posts: 660
Sorry CONF iture, "I can only encourage people to read these guys too and evaluate if they qualify for the name of nuts ..." does not work. I have. Those idiots don't have a real clue about science, strength of materials, or the difficulty of keeping something secret.

(My hobby during my days at Rockwell International Anaheim was taking very vague hints of what was going on in the black world and noting things like what they were not talking about and telling them what they were doing and offering suggestions. It was fun freaking some of them out when I hit it right on the head. You CANNOT keep something that large a secret. By now somebody should have published information about size of charges, locations, who did it, and all the rest. Some idiot savant like me would have broken the whole thing with details FAR FAR less vague and hand-wavey than those cretins.)
JD-EE is offline  
Old 9th Apr 2011, 03:14
  #3211 (permalink)  
 
Join Date: Jun 2009
Location: I am where I am and that's all where I am.
Posts: 660
PJ2, B2 and F-111 suggest that a plane can fly without a vertical stabilizer and swept back to the point of being triangular wings. If a computer can fly the plane a human could potentially learn how.

I suspect, however, that learning on the job in a crisis is not at all unlikely.
JD-EE is offline  
Old 9th Apr 2011, 04:52
  #3212 (permalink)  
 
Join Date: Oct 2009
Location: berlin
Posts: 152
For my money, "why the LACK of damage to the VS LE, it's sides, and rudder TE, not even scratches to the paint" has been the most compelling question from the release of photo number one the day it was spotted from the air, and confirmed with the divers recovering it.
ventus, your money.....

there is a big damage on the rudder, like a shark bit, and if the chrash angel is more vertical than +/-45 degree the inertia energie let rotate the VS backwards to the blue sea

even the NZ paint on the VS in perpignan swam without scratches in the water, after stall............... with the same shark bit..... grity
grity is offline  
Old 9th Apr 2011, 04:59
  #3213 (permalink)  
PJ2
 
Join Date: Mar 2003
Location: BC
Age: 73
Posts: 2,460
JD-EE;

Yes, well, aircraft can be designed to fly without a vertical stabilizer when ways of controlling yaw are provided as in the cases cited. Also, as you'd know, some military aircraft require fbw because they are too unstable, (hence highly maneuverable) to hand fly. I believe "learning how" wouldn't be the impediment.

I agree with your last comment JD-EE because it's been proven a number of times with crippled transport aircraft. The results are mixed but that doesn't negate the likelihood.

In my estimation, under the circumstances which the AF447 crew faced, (I am assuming RP in the left seat, F/O in the right), re-learning how to fly an A330 with a missing VS, whether in ideal conditions or (depending upon when it is assumed by others that the VS departed before impact), with a stream of ECAM messages and audio warnings, in turbulence, in darkness, in cloud, with no airspeed information is an unlikely proposition and would result in the outcome described in my post above.

Last edited by PJ2; 9th Apr 2011 at 05:15.
PJ2 is offline  
Old 9th Apr 2011, 05:09
  #3214 (permalink)  
 
Join Date: Jul 2009
Location: Not far from a big Lake
Age: 79
Posts: 1,461
JD-EE, A moment of thread drift here:
"I can only encourage people to read these guys too and evaluate if they qualify for the name of nuts ..."
They aren't nuts, but they are charlatans, and they are collecting money from the nuts they reel in for their cause. Their "explosives were used in the WTC " story is extremely flawed in that they have not accounted for the air trapped in the buildings as the upper floors came down like a monster piston.
Now back to AF447.
Machinbird is offline  
Old 9th Apr 2011, 05:32
  #3215 (permalink)  
dvv
 
Join Date: Jun 2007
Location: KIAD east downwind
Posts: 155
CONF iture, as I've read all the 9/11 NIST reports quite thoroughly, I can confidently say that all of them are very thorough, and none of the truthers' truthiness is anywhere close to the real scientific/engineering approach to facts and conclusions demonstrated by the NIST teams.

And oh, thanks for making my further reading of PPRuNe a bit more effective.
dvv is offline  
Old 9th Apr 2011, 07:04
  #3216 (permalink)  
PJ2
 
Join Date: Mar 2003
Location: BC
Age: 73
Posts: 2,460
CliveL;

Interesting regarding the possibility of flight without the VS, thank you. There is perhaps more controllability than I'm assuming?

However, I imagine your point regarding the hydraulic power seals the issue of controllability, as the rudder is powered by all three systems, (the THS by the blue and yellow) and a loss of fluid would be assured. That would leave engine thrust the only control for all three axes.

PJ2
PJ2 is offline  
Old 9th Apr 2011, 09:13
  #3217 (permalink)  
 
Join Date: Jul 2009
Location: France - mostly
Age: 81
Posts: 1,688
It seems "loss of control" is now amply explained.

How about arm '36g'?
HazelNuts39 is offline  
Old 9th Apr 2011, 09:37
  #3218 (permalink)  
 
Join Date: Jul 2009
Location: France - mostly
Age: 81
Posts: 1,688
Originally Posted by JD-EE
But that might allow enough airspeed pickup to allow the plane to get engines started and pull out to level flight.
Using full rudder would help getting the nose down. You didn't forget to extend the flaps on the other wing to permit rolling it back to wings level?
HazelNuts39 is offline  
Old 9th Apr 2011, 10:24
  #3219 (permalink)  
 
Join Date: Jun 2009
Location: I am where I am and that's all where I am.
Posts: 660
HN39, you asked "Using full rudder would help getting the nose down. You didn't forget to extend the flaps on the other wing to permit rolling it back to wings level?"

Um, I'd rather envisioned retracting the flap that was temporarily extended if the plane gathers too much speed to safely have flaps extended. Regardless, the concept is that once it was broken out of its "spin" you'd want to return to a symmetrical configuration. Otherwise you simply buy yourself new problems.
JD-EE is offline  
Old 9th Apr 2011, 10:57
  #3220 (permalink)  
Moderator
 
Join Date: Apr 2001
Location: various places .....
Posts: 6,717
http://www.pprune.org/tech-log/376433-af447.html links to a second locked thread on this subject.
john_tullamarine is offline  

Thread Tools
Search this Thread

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

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.