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

AF 447 Search to resume (part2)

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

AF 447 Search to resume (part2)

Old 2nd May 2011, 17:54
  #541 (permalink)  
bearfoil
Guest
 
Posts: n/a
dufc

I agree that it is stipulated that there is a contingent of BEA sceptics aboard. I think the repetition may come from anxiety that it will be overlooked, as BEA's history is well defended here also. Perhaps a truce until we have more results in the form of releases of prose and pictures.

More importantly, I apologize to anyone who was offended by my choice of the word "fun" in describing my experiences here. It was selfish, and unthinking. In my defense I will say that I have spent far more time in some anxiety and gloom, thinking of how the people may have felt in their last moments. A better word(s) would by rewarding, and fascinating.
 
Old 2nd May 2011, 17:57
  #542 (permalink)  
PJ2
 
Join Date: Mar 2003
Location: BC
Age: 72
Posts: 2,429
Chris;
I think the Americans can lay claim to having caught up with the Brits by now...
I really wonder if they are. I know Canada isn't. Canada has no CARS governing flight data analysis programs. The programs are entirely voluntary with no specifications on parameters or data handling. I believe the JARs are well ahead of this.

The FAA Mandatory parameters are:

- For FDAU-equipped aircraft, (Flight Data Aquisition Unit) manufactured before October 11, 1991, 22 parameters are mandatory;
- After that date, 34 parameters are mandatory
- After August 20, 2000, 57 parameters are required;
- After August 19, 2002 88 parameters are required.

Canada's requirement is essentially the same.

Eighty-eight parameters is barely adequate in terms of investigative capability.

Functional checks of the mandatory parameters are required once per year.

EASA has proposed rules requiring internal self-monitoring of mandatory parameters so that failures, (even the silent kind where a recorder just quits) can be addressed immediately instead of the next check, which could theoretically be 364 days away.

QARs for FOQA programs routinely record up to 2000 parameters many times at rates higher than required. The requirement for SSFDRs remains minimal while voluntary programs are exceeding minimums by a substantial amount. However, the FOQA QAR is mounted in or under the cockpit in the same area as the FDAU/DFDAU and as such is not crash-proof.

Upgrade and rule changes are driven by cost, not need.



The Honeywell 980-4700-42 was capable of 1300 parameters.
PJ2 is offline  
Old 2nd May 2011, 18:06
  #543 (permalink)  
 
Join Date: Nov 2005
Location: London
Posts: 16
Anyone with a rudimentary understanding of French may be interested in the downloadable video clips on the BEA.aero website, in particular the one relating to the 'first dive'. This screengrab shows a labelled debris field...

dinbangkok is offline  
Old 2nd May 2011, 18:51
  #544 (permalink)  
 
Join Date: May 2008
Location: USA
Posts: 44
Did anyone notice that the clear container with a CSMU inside in the lower left hand corner of this picture: http://www.bea.aero/fr/enquetes/vol....mages/fdr3.jpg is the same one that the recovered CSMU is inside in the last picture in this sequence: Information, 2 May 2011 . I saw a quick video clip of the CMSU being put into the clear box this morning and noted that it was the same as the one that slf99 pointed out in the first picture supposedly taken before the CSMU was recovered.
areobat is offline  
Old 2nd May 2011, 18:59
  #545 (permalink)  
 
Join Date: Jan 2008
Location: Blighty (Nth. Downs)
Age: 73
Posts: 2,082
PJ2,

Yes, I might have mentioned that all the SESMA and maintenance-monitoring data is acquired from the QAR in the avionics bay near the cockpit. On BA short-haul, the QAR cassette is changed every 24 hrs, normally at base; not sure what happens on long-haul.

It does seem unfortunate when crash-resistant DFDRs record only the legal minimum of data, but I don't know how the JARs compare with FARs. As for AF447, 1300 parameters sounds impressive, but one also hopes all the differing sample rates will prove to be enough for this investigation.

If AF447 impacted nose-up, I wonder if there could still be a chance of finding an intact QAR cassette...
Chris Scott is offline  
Old 2nd May 2011, 19:14
  #546 (permalink)  
 
Join Date: Feb 2011
Location: Nearby SBBR and SDAM
Posts: 873
High energy impact

If AF447 impacted nose-up, I wonder if there could still be a chance of finding an intact QAR cassette...
The remains of the radome enables us estimate the forces in the a/c nose section.
RR_NDB is offline  
Old 2nd May 2011, 20:10
  #547 (permalink)  
PJ2
 
Join Date: Mar 2003
Location: BC
Age: 72
Posts: 2,429
Chris;

The SESMA program is excellent from what I know about it. Understand the download process.

I'm led to believe that the QAR is an optical disc rather than a PCMCIA card. Either way, I have doubts about survival/readability of the medium but we won't know until the unit is located and recovered. That may be a priority after the SSCVR is located and recovered and both sent to France, (I wonder if they'll send them on separate aircraft?).
PJ2 is offline  
Old 2nd May 2011, 20:53
  #548 (permalink)  
 
Join Date: Feb 2011
Location: Nearby SBBR and SDAM
Posts: 873
QAR media

PJ2,

At pg 6 the vendor sez both cards (Optical disk or PC card):

http://www.teledyne-controls.com/pdf/FDMS-Brochure.pdf

But here:

http://www.teledyne-controls.com/pdf/OQAR_brochure.pdf

If the unit was not crushed there are chances to recover the cassete info.

On LHR 777 i wrote (Pt):

Soft landing, Hard landing ou Crash landing? | insiderNews

With an analogy between World Economy hit by US financial Tsunami and the BA 777 at LHR. A short article for a Stock Market website.
RR_NDB is offline  
Old 2nd May 2011, 21:00
  #549 (permalink)  
 
Join Date: Jul 2007
Location: My Stringy Brane
Posts: 377
Vidcaps from BEA video "Premiere Plongee":
















Composite of 3 vidcaps to reveal a bit more:

Machaca is offline  
Old 2nd May 2011, 21:17
  #550 (permalink)  
 
Join Date: Mar 2002
Location: Florida
Posts: 5,248
The remains of the radome enables us estimate the forces in the a/c nose section.
I don't think so.

The soft frangible parts are extremely difficult to decipher vectors. Far easier to look at the strongest parts of the aircraft like the cockpit or engines or at least something with wide breadth to it.
lomapaseo is offline  
Old 2nd May 2011, 21:38
  #551 (permalink)  
 
Join Date: Mar 2011
Location: engineer at large
Posts: 1,409
Did anyone notice that the clear container with a CSMU inside in the lower left hand corner of this picture:
This is a mockup to train for the recovery...

Then once they bring it up, it has to be sealed in fresh water for an amount of time to leach out any salt intrusions, and perhaps pressure treatment.

(if you look closely, you will see that the 2 images are not of the same containment vessel)
FlightPathOBN is offline  
Old 2nd May 2011, 21:44
  #552 (permalink)  
 
Join Date: Feb 2011
Location: Nearby SBBR and SDAM
Posts: 873
Falling tail first and "aluminum shower" speed

lomapaseo,

What i thought:

1) a/c hit surface at pitch 5~15
2) nose drops
3) lower part of radome breaks in several parts
4) higher part (the one found) shows coherence to the model at 1) and 2)

I agree that for evaluate gs better to look not to light composites.

The radome was my "reference" of the impact of a/c nose cone "falling"

In a low energy impact would just break and detach. It shown like crushed from vertical deceleration despite its lightweight.

Question:

Supposing first impact at tail and second at a/c nose. (falling some degrees pitch up) how we compare the gs. My feeling is the second (nose) is more intense. Is it a valid assumption? The difference may be negligible, i guess.

PS

We can imagine the "aluminum shower" in the water to the bottom.

Question:

Roughly how many minutes estimated? Supposing no big currents.

Last edited by Jetdriver; 3rd May 2011 at 16:50.
RR_NDB is offline  
Old 2nd May 2011, 21:58
  #553 (permalink)  
 
Join Date: Mar 2011
Location: engineer at large
Posts: 1,409
Mac,

What are you trying to figure out?

We can imagine the "aluminum shower" in the water to the bottom.
Question:
Roughly how many minutes estimated? Supposing no big currents.
There are many factors.....
FlightPathOBN is offline  
Old 2nd May 2011, 22:32
  #554 (permalink)  
 
Join Date: Feb 2011
Location: Nearby SBBR and SDAM
Posts: 873
Mind models

FlightPathOBN,

In order to imagine some models:

After a/c hit water how many feet (horizontal) the debris probably traveled?

They publicized the xy coordinates of the wreckage?

Whats the wreckage field distance to LKP?

The question of "dive time" is because they mentioned "sea currents" for defining search area priorities.

And considering the debris concentration this appears to me meaningless.

And it seems revealing "gross errors". Why? Just delayed the investigation.

Last edited by Jetdriver; 3rd May 2011 at 16:51.
RR_NDB is offline  
Old 2nd May 2011, 23:24
  #555 (permalink)  
 
Join Date: Mar 2011
Location: engineer at large
Posts: 1,409
RR,

Not sure what delayed the investigation means.

I have significant experience in underwater recovery.

There are many factors, when even if you know the surface impact point, determine the search grid and potential bottom location.

I understand the depth of the 447 was substantial. This in itself, leads to quite a bit of research to ascertain the bottom location. All of the materials will ave a relative density as in relates to the seawater. The seawater also has bands of density in relation to currents, temperatures, salinity, and MET factors. Surface conditions at the time of impacts need to be considered as well.

The oceans have different describable levels, as levels of dense, cold water, will migrate, much as the currents in the air. Pilots are aware of all of the different layers of air, temperature, and density, and the gulf stream affects, the same is true of the underwater 'currents', nothing is ever static.

You mentioned the 'aluminum shower', well the debris field can be theoretically calculated, but as we have all noted in the Titanic, that mass took quite the effort to find. The pieces of the aircraft would have a relative density to the seawater on descent, not to mention the buoyancy effects of the shapes in flutter. Given that, the denser, less aerodynamic pieces, would tend to descend rapidly, hence, more directly straight down, and due to pressure at depth, would potentially accelerate at the same rate. I believe what we are seeing in the underwater images, is all of the 'pieces' of the near the same relative aerodynamic density with regards to the descent.
To me, this means that the impact of the vessel had little forward momentum, as the density of impact, had there been significant forward motion, would have left assemblies of relative density along a trail.
FlightPathOBN is offline  
Old 2nd May 2011, 23:52
  #556 (permalink)  
 
Join Date: Feb 2001
Location: UK
Posts: 647
How can 100-200g relate to the relatively undamaged galley unit (sorry I forget the correct name but Im sure the experts know what I mean)?
chrisN is offline  
Old 3rd May 2011, 00:20
  #557 (permalink)  
 
Join Date: Mar 2011
Location: engineer at large
Posts: 1,409
Chris,

Can you explain further....

A 'unit' may have characteristics that 'fly' or have specific properties underwater.

Forensic Taphonomy is a pseudo science, and there is certainly an artform associated with the forensic evaluations.....
FlightPathOBN is offline  
Old 3rd May 2011, 00:54
  #558 (permalink)  
 
Join Date: Mar 2002
Location: Florida
Posts: 5,248
ChrisN

How can 100-200g relate to the relatively undamaged galley unit (sorry I forget the correct name but Im sure the experts know what I mean)?
Are you talking about decell rates?? and where did they come from??

With a car, your bumper, grill and fenders do a great job of taking an instantaneous high G load and spread it over a couple of seconds before you feel it. In that period of time much energy is being absorbed to lessen the load on your innards.

OTOH if you manage to get a uncrushable object like an engine block between you and the immovable brick wall your G loads are gonna be a lot higher.

Many of the box structures a couple of feet above the airplane keel beam are not gonna feel the same load as the belly structure simply due to the crushing and speading out in area of the load as well as in time.

All I'm doing in this explanation is explaining why your eye sees things the way they are in a photo.

In real life I've seen occupants that have survived sitting within feet of those that haven't all due to variances in G load and their relative nearness to an unbuckled part of the airframe in a given accident.
lomapaseo is offline  
Old 3rd May 2011, 00:55
  #559 (permalink)  
 
Join Date: Feb 2011
Location: Nearby SBBR and SDAM
Posts: 873
Shape of debris field an orientation

FlightPathOBN,

I am speaking on the first searches far from LKP. They spent time and effort doing that and delaying the current phase.

Amazingly wreckage is very near LKP. How near? Any info. on the distance?

The shape of debris field and orientation are related to the direction the plane hit sea surface? They informed the direction?

In a previous post i made some questions on travel time of debris. How much time you estimate? In your opinion the debris did fall near vertical?

What surprised me was the concentration of them. And the flat terrain.

Last question: Whats the estimated temperature at bottom?
RR_NDB is offline  
Old 3rd May 2011, 01:00
  #560 (permalink)  
bearfoil
Guest
 
Posts: n/a
chrisN

Howdy. Lomapaseo's proposed g values are astronomic, and frankly, it is hard to disagree with him. I have offered my experience of dealing with similar structures in falls and warehouse damage that exhibited far more damage than the Galley stack, and some other recovered bits. It is a monstrous disconnect, one I cannot get my arms around, at all. If she hit tail on, in a flat aspect, the cockpit became the crack on the whip, perhaps even accelerating as the tail stopped. The forward part of the a/c hit with certainly the same velocity as the tail, if not more. The crew rest, in the hold, suffered a severe display of flattening, not just from stopping on the hold floor, (and the sea's surface), but then suffering the collapse of two more diaphragms on top, the cabin floor, and the dorsal skin of the fuse.

Initially, I thought a hull rupture at altitude had allowed some contents to spill out, which would have had a far less emphatic impact with the sea, being in free fall, etc. I don't think that is wrong, but I continually adjust the altitude at which the contents separated from the a/c. Beyond the impact, the potential damage to be done as the a/c spreads out in a surface field on a stormy sea, and the potential for damage beyond that which pieces may have endured on impact, the galley cabinet with its intact food boxes is either a miracle or a hint at separation from the hull prior to impact. In any case, if photos of the cockpit are allowed, the disconnect will be affirmed as other than simultaneous and co-located sea entry, imo.
 

Thread Tools
Search this Thread

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

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.