Hot: Air France Jet Missing (AF 447)

It is deep very deep. So says CNN. They stated the depth is about the same as the height of Mt. Everest at about 16000-17000 feet. Nice, I guess they accept a 50% margin of error.
 
Last heard was that US is sending its Deep Sea Subs with listening devices, that can listen to the frequency sent out by the black box. basically subs can travel to max. permissible structural limits(the depth untill which the hull can withstand the external h2o pressure and not explode)which should be pretty deep but, for recovery purposes, unmanned subs would be used which can go any deeper untill they can be tracked.
 
Cptnchia said:
As far as you know they can't. I know some Seals who might disagree with you though.
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You aren't supposed to know about that stuff!:cool:

However, I stand by my statement...at 16,000' there is no hatch that will open to let people out. At that depth, anybody would be crushed...I'm just sayin':insane:
 
bravoalphakilo said:
Last heard was that US is sending its Deep Sea Subs with listening devices, that can listen to the frequency sent out by the black box. basically subs can travel to max. permissible structural limits(the depth untill which the hull can withstand the external h2o pressure and not explode)which should be pretty deep but, for recovery purposes, unmanned subs would be used which can go any deeper untill they can be tracked.
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I realize this is semantics....but I'm certain you meant IMPLODE. Not much exploding going on at the bottom of the ocean. :dunno:
 
Cptnchia said:
You might be suprised by what I know. Or not.:dunno:
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I have no clue of your background so I would not guess as to what you know or do not know. I was trying to bring some levity to a sad subject. I do agree there are some neat "tricks" the Navy has with subs...I'm sure there are some things I have no clue about (I was not a "bubblehead") when it comes to the underwater community. I did know about the SeAL's extraction techniques. Those guys definitely have my respect!!!



I think it would be obvious common sensewise that the recovery will not be by humans.
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And that was my only point.:D
 
Stone Cold said:
That's classified...for the layman, just know it can go deeper than you can hold your breath!!;)


Honestly, I have no clue. I'm sure they have them looking for the "pinger" so they can locate it and will send in deep submersibles, since the hatch does not let them out of the sub at depth!:panic::D
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I think the US Navy gives out these test depths:
LA class 688/I > 600 ft
Seawolf and Virginia class > 850 ft
I also haven't a clue and they obviously aren't going to be the recovery platform.
I think the important things is that they make a better sonar platform than surface ships due to the ability to get below the thermocline to hear the pingers.
Recovery would be by some sort of manned or unmmaned DSV.
 
granlistillo said:
I think the important things is that they make a better sonar platform than surface ships due to the ability to get below the thermocline to hear the pingers.
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My understanding of ocean acoustics is that there are layers where the acoustic/chemical/mechanical/etc. characteristics of the fluid are different, which can strongly attenuate energy transmission between layers.

Is it uncommon for naval surface vessels to have a sonar-on-a-stick (i.e., a microphone that can be lowered a thousand feet or so)?
 
Minuteman said:
My understanding of ocean acoustics is that there are layers where the acoustic/chemical/mechanical/etc. characteristics of the fluid are different, which can strongly attenuate energy transmission between layers.

Is it uncommon for naval surface vessels to have a sonar-on-a-stick (i.e., a microphone that can be lowered a thousand feet or so)?
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If you read Tom Clancy's Hunt for Red October, most US vessels have a tail, which they can send at various depths. The Helos and P-3s can launch sonobouys as well at various depths. You are correct that temperatures, salinity, and pressure cause various sound layers, meaning if your microphone was in one layer, it may never hear the sound in the other layer.
 
mjg407 said:
You are correct that temperatures, salinity, and pressure cause various sound layers, meaning if your microphone was in one layer, it may never hear the sound in the other layer.
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There is a similar phenomenon with the atmosphere and an early morning inversion. When I was a F4 mech I remember the ear splitting scream of J79s taking off with the morning inversion.
 
mjg407 said:
If you read Tom Clancy's Hunt for Red October, most US vessels have a tail, which they can send at various depths. The Helos and P-3s can launch sonobouys as well at various depths. You are correct that temperatures, salinity, and pressure cause various sound layers, meaning if your microphone was in one layer, it may never hear the sound in the other layer.
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Subs have towed arrays that can be deployed way behind the sub and away from the subs own noise. The slower the subs travels the lower the array can be dipped to help it get below any thermal layers.
 
Minuteman said:
My understanding of ocean acoustics is that there are layers where the acoustic/chemical/mechanical/etc. characteristics of the fluid are different, which can strongly attenuate energy transmission between layers.

Is it uncommon for naval surface vessels to have a sonar-on-a-stick (i.e., a microphone that can be lowered a thousand feet or so)?
Click to expand...


There isn't a layer or layers of water that makes one depth of ocean different from one another. It's all based on the local speed of sound at that particular depth. Pressure, Temperature and Salinity affect the speed of sound. We use an average speed of sound in water of 3,000kts for some calculations.

Sound will travel to where the speed of sound is slower. So the only way to figure out where sound is going to go is to drop an XBT to get a sound velocity profile.

Where you get the "layer" is where one factor (like temperature) affecting the speed of sound overrides another factor (pressure) affecting the speed of sound. As pressure increases, the speed of sound increases. As temperature increases the speed of sound increases. As salinity increases, the speed of sound decreases.

Water temperature will usually be highest near the surface. So the speed of sound will be higher near the surface. So sound will tend to travel deeper.

As you go deeper, pressure increases so the speed of sound will increase and turns the sound back towards the surface. That depth where sound turns back towards the surface - that is the layer. (that is a very simplified explanation.)


As far towed microphones go - submarines have them - surface ships have them. The microphone is 1200ft long. Surface ships can get them down to about 2000-2500ft. I don't know how deep a submarine can drag their array - but they obviously have an advertised 600-800ft head start as the advertised max depth for submarines is around 600-800ft. Ships get their array down so that they can listen below the layer. A submarine already can hide below the layer so they don't have as much of a pressing need to get their towed array any deeper since they're looking for another submarine not pingers.
 
Subject: Air France Accident: Smoking Gun Found

I found this on another forum while browsing about the Airbus..... seems like a good quick read.... makes sense... what ya'll think?

A Brazilian Naval unit reportedly found the complete = vertical fin/rudder assembly of the doomed aircraft floating some 30 miles = from the main debris field. The search for the flight recorders goes on, but given the failure = history of the vertical fins on A300-series aircraft, an analysis of its = structure at the point of failure will likely yield the primary cause factor = in the breakup of the aircraft, with the flight recorder data (if found) = providing only secondary contributing phenomena.

The fin-failure-leading-to-breakup sequence is strongly suggested in the = attached (below) narrative report by George Larson, Editor emeritus = of Smithsonian Air & Space Magazine.

It's regrettable that these aircraft are permitted to continue in routine flight = operations with this known structural defect. It appears that safety finishes = last within Airbus Industries, behind national pride and economics. = Hopefully, this accident will force the issue to be addressed, = requiring at a minimum restricted operations of selected platforms, and grounding = of some high-time aircraft until a re-engineered (strengthened) vertical = fin/rudder attachment structure can be incorporated.

Les

--------------------------(George Larson's Report)---------------------

This is an account of a discussion I had recently with a maintenance professional
who salvages airliner airframes for a living. He has been at it for a while, = dba BMI
Salvage at Opa Locka Airport in Florida. In the process of stripping parts, he sees =
things few others are able to see. His observations confirm prior assessments of
Airbus structural deficiencies within our flight test and aero = structures communities
by those who have seen the closely held reports of A3XX-series vertical fin failures.

His observations:

"I have scrapped just about every type of transport aircraft from = A-310,
A-320, B-747, 727, 737, 707, DC-3, 4, 6, 7, 8, 9, 10, = MD-80, L-188, L1011
and various Martin, Convair and KC-97 = aircraft.

Over a hundred of them.

Airbus products are the flimsiest and most = poorly designed as far as
airframe structure is concerned by an almost = obsession to utilize composite
materials.

I have one A310 = vertical fin on the premises from a demonstration I just
performed. It was pathetic to see the composite structure shatter as it did,
something a Boeing product will not do.

The vertical fin along with the = composite hinges on rudder and elevators is
the worst example of structural = use of composites I have ever seen and I am
not surprised by the current = pictures of rescue crews recovering the
complete Vertical fin and rudder assembly at some distance from the crash
site.

The Airbus line has a history of both multiple rudder losses and a vertical
fin and = rudder separation from the airframe as was the case in NY with AA.

As an old non-radar equipped DC4 pilot who flew through many a = thunderstorm
in Africa along the equator, I am quite familiar with their = ferocity. It is not
difficult to understand how such a storm might have stressed an aircraft
structure to failure at its weakest point, and especially so in the presence of
instrumentation problems.

I replied with this:

"I'm = watching very carefully the orchestration of the inquiry by French
officials and Airbus. I think I can smell a concerted = effort to steer
discussion away from structural issues and onto sensors, = etc. Now Air
France, at the behest of their pilots' union, is = replacing all the air data
sensors on the Airbus fleet, which creates a = distraction and shifts the
media's focus away from the real problem.

It's difficult to delve into the structural issue without wading into the
Boeing vs. Airbus swamp, where any observation is instantly = tainted by its
origin. Americans noting any Airbus structural issues = (A380 early failure
of wing in static test; loss of vertical surfaces in = Canadian fleet prior to
AA A300, e.g.) will be attacked by the other side = as partisan, biased, etc. "

His follow-up:

One gets a really unique insight into = structural issues when one has
first-hand experience in the dismantling process.

I am an A&P, FEJ and an ATP with 7000 = flight hours and I was absolutely
stunned, flabbergasted when I realized that = the majority of internal
airframe structural supports on the A 310 = which appear to be aluminum are
actually rolled composite material with = aluminum rod ends. They shattered.

Three years ago we = had a storm come through, with gusts up to 60-70 = kts.,
catching several A320s tied down on the line, out in the = open.

The A320 elevators and rudder hinges whose actuators had been
removed shattered and the rudder and elevators came off.

Upon = closer inspection I realized that not only were the rear spars
composite = but so were the hinges. While Boeing also uses composite
material in its airfoil structures, the actual attach fittings for the elevators,
rudder, vertical and horizontal stabilizers are all of machined aluminum."
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Re: Subject: Air France Accident: Smoking Gun Found

cencal83406 said:
I found this on another forum while browsing about the Airbus..... seems like a good quick read.... makes sense... what ya'll think?
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sounds a bit like anti french propaganda to me. I can't vouch for the authenticity of the scrap man's findings but it all reads like freedom fries!
 
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