AF 447 Search to resume (part2)
Join Date: Jul 2009
Location: SUSSEX UK
Age: 76
Posts: 57
Likes: 0
Received 0 Likes
on
0 Posts
@jcjeant
I think this may be galvanic action where the aluminium housing of the pinger is acting as an anode and is corroding rather than the ferrous cylinder. Further evidence of this is that there appears far less rust on the CVR cylinder than the FDR which has lost its pinger, and hence no sacrificial anode to stop it rusting. There needs to be an electrical path between pinger and cylinder for the effect to occur, which I assume is there somewhere.
Galvanic anode - Wikipedia, the free encyclopedia
Sacrificial protection on the hull of a ship using a Zinc anode.
Zinc anodes protect the steel parts of the hull | Flickr - Photo Sharing!
Concretions on the CVR pinger ..... indication of a crack ?
Galvanic anode - Wikipedia, the free encyclopedia
Sacrificial protection on the hull of a ship using a Zinc anode.
Zinc anodes protect the steel parts of the hull | Flickr - Photo Sharing!
The only suggestion of independent power supply that has emerged was after SR111 and that was the voice recorder.
Corrosion on pingers ?
If it's corrosion on the pingers, it is probably galvanic corrosion ( occurs between metals of different potentials in seawater).
But since the waranty ends after 30 days at sea, I don't think the designers cared about this.
But since the waranty ends after 30 days at sea, I don't think the designers cared about this.
Last edited by DJ77; 4th May 2011 at 17:11. Reason: Ooops, BJ-ENG fired first.
Join Date: Sep 2007
Location: Germany
Posts: 152
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by ChristiaanJ
Even without a vertical tail, the rear end of the fuselage provides some "weathervane" stability, ...
A swept wing without a fuselage doesn't need a VS to fly:
Horten Nurflugels
Join Date: Jan 2005
Location: France
Posts: 2,315
Likes: 0
Received 0 Likes
on
0 Posts
Caygill,
"If you lose all power on a modern aircraft..."
Rare... since there are batteries, and inverters to generate some essential AC from the 28V DC battery bus.
Us engineers are not quite as stupid as you seem to think.
RTFD... and so far I've seen almost nothing about the A330 system.
RR_NDB has a few points.
"If you lose all power on a modern aircraft..."
Rare... since there are batteries, and inverters to generate some essential AC from the 28V DC battery bus.
Us engineers are not quite as stupid as you seem to think.
RTFD... and so far I've seen almost nothing about the A330 system.
RR_NDB has a few points.
Join Date: Jan 2005
Location: France
Posts: 2,315
Likes: 0
Received 0 Likes
on
0 Posts
Join Date: Sep 2007
Location: Germany
Posts: 152
Likes: 0
Received 0 Likes
on
0 Posts
Join Date: Jan 2005
Location: France
Posts: 2,315
Likes: 0
Received 0 Likes
on
0 Posts
OK, bear, never heard that term for the 737...
Saw 'Fat Albert' a few times, then found that that particular 'sobriquet' had shifted to the C-130....
I like the 737, less of a noisy flying Coke can than the A320 family, from the SLF point of view.
[/offtopic]
Guest
Posts: n/a
OleOle
I flew a Manta 'Wing' in the seventies, so am familiar. Just a little fun poked at Jack Northrop and his obsession. At a billion dollars a copy, the B-2 is less a flying wing than an airborne Bank, or money sewer, depending on one's pov.
ChristiaanJ
Then there is the BUFF. Boeing gets the familiars, eh??
I flew a Manta 'Wing' in the seventies, so am familiar. Just a little fun poked at Jack Northrop and his obsession. At a billion dollars a copy, the B-2 is less a flying wing than an airborne Bank, or money sewer, depending on one's pov.
ChristiaanJ
Then there is the BUFF. Boeing gets the familiars, eh??
And what tells you that's not already the case?
Unless you have the full WDM for the A330 at hand....
Unless you have the full WDM for the A330 at hand....
18V DC is derived for the CVR area mic preamp, from the 115V AC supply delivered to the CVR.
Join Date: Feb 2011
Location: Nearby SBBR and SDAM
Posts: 875
Likes: 0
Received 0 Likes
on
0 Posts
Trying to keep some VS effect for a minimum of "airworthiness "
ChristiaanJ,
The separation of VS in both cases (AA587 and AF447) occurred at itīs "coupling" to the fuselage. This "coupling" in EADS design appears to be the "point" that fail when the loads exceed the specs. The "connection" between "conventional metal" to "new materials" advanced VS structure.
Question:
Wouldnīt be better/safer to have a "tapered design" with greater "Fault Tolerance" and "Graceful Degradation".
I mean:
Considering the main reason for a big VS is for take off * why not to have a tapered (strength) design?
To keep some VS effect even after exceeding specs limits (due any reason)
(*) Exceptions: Windy and cross wind Landing
Rationale:
Redundancy, fault tolerance and graceful degradation are "defense lines" against our "nightmare": Murphyīs law.
The separation of VS in both cases (AA587 and AF447) occurred at itīs "coupling" to the fuselage. This "coupling" in EADS design appears to be the "point" that fail when the loads exceed the specs. The "connection" between "conventional metal" to "new materials" advanced VS structure.
Question:
Wouldnīt be better/safer to have a "tapered design" with greater "Fault Tolerance" and "Graceful Degradation".
I mean:
Considering the main reason for a big VS is for take off * why not to have a tapered (strength) design?
To keep some VS effect even after exceeding specs limits (due any reason)
(*) Exceptions: Windy and cross wind Landing
Rationale:
Redundancy, fault tolerance and graceful degradation are "defense lines" against our "nightmare": Murphyīs law.
Join Date: Mar 2001
Location: us
Posts: 694
Likes: 0
Received 0 Likes
on
0 Posts
Very long New York Times article on the finding of AF 447.
What Happened to Air France Flight 447? - NYTimes.com
There is a lot of history, and some theorizing. Quite a bit of information on the autopsies, with the doctor indicating that he couldn't rule out that some might have survived the initial impact.
What Happened to Air France Flight 447? - NYTimes.com
There is a lot of history, and some theorizing. Quite a bit of information on the autopsies, with the doctor indicating that he couldn't rule out that some might have survived the initial impact.
Guest
Posts: n/a
RR NDB
"Sequential Failure". A time worn concept, whether "crumple zone", or ablative skin.
The problem is at least "twofold". One is the almost unavoidable problem of mating plastic to metal, mechanically (1), or bonded (2).
On the Airbus VS it is mechanical. This presents the "focal energy" obstacle. A concentration of stress in Epoxy/Reinforced structures is counter intuitive to the material's strong point. Thus a dowel, pin, or clevis, bracket system focuses failure sums of energy on an assembly whose design is related to stress/spread for maximum load areas. Note the A350 has gone to 5 (five) saddle/pin systems.
The second, bonded, is universally avoided unless some spread can be attained.
The most important consideration is the fact that this most critical assembly is "surface mounted". This concentrates virtually all Stresses on an inescapably small area. The VS/Rudder is vertically cantilevered, a swell looking and very efficient way to alleviate drag from external wetted areas.
However.......
edit... I cannot locate the "lateral rods" on the bare aft fuse of the 587 A300. These were added to later a/c....... There are pictures of these rods on the VS (447). After the fact design, hmmm.......
edit... Disregard, I did find a remnant of the "Lateral Rod" on aft bracket.
sorry...
"Sequential Failure". A time worn concept, whether "crumple zone", or ablative skin.
The problem is at least "twofold". One is the almost unavoidable problem of mating plastic to metal, mechanically (1), or bonded (2).
On the Airbus VS it is mechanical. This presents the "focal energy" obstacle. A concentration of stress in Epoxy/Reinforced structures is counter intuitive to the material's strong point. Thus a dowel, pin, or clevis, bracket system focuses failure sums of energy on an assembly whose design is related to stress/spread for maximum load areas. Note the A350 has gone to 5 (five) saddle/pin systems.
The second, bonded, is universally avoided unless some spread can be attained.
The most important consideration is the fact that this most critical assembly is "surface mounted". This concentrates virtually all Stresses on an inescapably small area. The VS/Rudder is vertically cantilevered, a swell looking and very efficient way to alleviate drag from external wetted areas.
However.......
edit... I cannot locate the "lateral rods" on the bare aft fuse of the 587 A300. These were added to later a/c....... There are pictures of these rods on the VS (447). After the fact design, hmmm.......
edit... Disregard, I did find a remnant of the "Lateral Rod" on aft bracket.
sorry...
Join Date: Jan 2008
Location: uk
Posts: 857
Likes: 0
Received 0 Likes
on
0 Posts
In contrast, in AF447 the couplings did not fail and were still attached to the VS along with bits of the fuselage. The rear fuselage itself failed. BEA first report has images (P39): http://www.bea.aero/docspa/2009/f-cp...90601e1.en.pdf
Join Date: Dec 2010
Location: Middle America
Age: 84
Posts: 1,167
Likes: 0
Received 0 Likes
on
0 Posts
Bear
Think you got your numbers mixed up, it isn't a 737, it is a 377 Super Guppy
http://upload.wikimedia.org/wikipedi...SA_landing.jpg
Think you got your numbers mixed up, it isn't a 737, it is a 377 Super Guppy
http://upload.wikimedia.org/wikipedi...SA_landing.jpg
Join Date: Feb 2001
Location: right here inside my head
Age: 65
Posts: 178
Likes: 0
Received 0 Likes
on
0 Posts
Quote:
Originally Posted by RR_NDB
ChristiaanJ,
The separation of VS in both cases (AA587 and AF447) occurred at itīs "coupling" to the fuselage.
No it didn't. In AA587 as shown in your images, the VS structure was torn off the couplings.
In contrast, in AF447 the couplings did not fail and were still attached to the VS along with bits of the fuselage. The rear fuselage itself failed. BEA first report has images (P39): http://www.bea.aero/docspa/2009/f-cp...90601e1.en.pdf
Originally Posted by RR_NDB
ChristiaanJ,
The separation of VS in both cases (AA587 and AF447) occurred at itīs "coupling" to the fuselage.
No it didn't. In AA587 as shown in your images, the VS structure was torn off the couplings.
In contrast, in AF447 the couplings did not fail and were still attached to the VS along with bits of the fuselage. The rear fuselage itself failed. BEA first report has images (P39): http://www.bea.aero/docspa/2009/f-cp...90601e1.en.pdf