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-   -   AF 447 Search to resume (https://www.pprune.org/tech-log/395105-af-447-search-resume.html)

vovachan 7th Jan 2010 16:28

I think it is terribly important they raise the Titanic... er... AF447

As in the case of the Titanic, there is an experienced crew, following SOP, and then Bam!

Unusual Attitude 7th Jan 2010 16:28

The tendering process for the 3rd search is in the closing stages with an extensive team also working on a refined search area. Not much else to report I suspect until the contract is awarded and the vessels etc are underway.

iakobos 7th Jan 2010 18:53

Just the trace of an idea...

CVR/FDR, all well until they are located, recovered and in readable condition.
What we are looking essentially at is the location of the frame.

Relying on HF or satellite-based comms has too many limitations and drawbacks.

So, what about transmitting/broadcasting the information simply to other crafts in the "vicinity" ?
Vicinity has to be understood as 400 to 850km, being the respective line of sight distances from one plane at 30k ft to another at sea level (worst case), and two planes at 35k ft (best case).

Every craft (flying out of radar coverage that is) would have a simple and inexpensive transceiver and related antenna, VHF or UHF (the lower the best) with data storage capability. That memory would be fed in real time with position data, possibly also with some other critical data.
Transmission, continuous until "manual reset" by the cockpit, would be triggered (automatically) only in case of "abnormal/emergency" situation.

It would be received by all aircraft in the said vicinity, from where it either could be forwarded to their ACARS transmitter for forwarding, or simply stored and read upon arrival. Many scenarii are possible.
H/W cost per craft: 4 cifers.

mm43 7th Jan 2010 19:45

@jakobos

So, what about transmitting/broadcasting the information simply to other crafts in the "vicinity" ?
Excuse me, but this suggestion in many forms has been raised and debated in this and other AF447 threads for some time.

It is doomed to fail, for one the infrastructure doesn't exist, and secondly there are some very lonely Oceanic routes out there where the chances of having other aircraft within the 'so-called' range would be minimal. The Buenos Aries (EZE) to Auckland (AKL) route is one that comes to mind - 5,600NM, and for 5,000NM of the track, the chances of having reciprocal or same direction traffic in range is basically zip/zero, i.e. the sole westbound aircraft becomes the sole eastbound service on the return leg.

mm43

JamesCam 7th Jan 2010 20:04


As to djp's suggestion about a "listener".... I like it!
Contrary to what tuj says, "listening", with modern technology, would consume far less power than regular "pings".
So pinging for a few weeks, then listening for a few months, is a good idea. It would need a new module inside the FDR and CVR (or rather inside the beacon), which doesn't exist yet, so whether there will be enough of an impetus to update the beacons, for what is a rare occurrence, is an open question.

The boxes would have to only listen say every 15 mins for a few seconds as the search vessel can carry a high powered transmitter and sensitive receiver which is operating continuously with a ping/listen cycle. if the CVR/FDR hears the ping during its listening period it immediately responds with its reply ping which is repeated for say a few minutes.

In this way, power consumption during idle periods would be minute; probably in the order of microamps, just powering a timer.

James

Graybeard 7th Jan 2010 21:18

The CVR/FDR is a fortified box inside the frangible orange box you see on an intact airplane. The pinger, an afterthought, is bolted to the outside of the frangible box. There is no electrical nor direct mechanical connection between the pinger and the fortified box. Any improvement to the pinger would likely have to be done inside the fortified pinger.

GB

ChristiaanJ 7th Jan 2010 21:27

JamesCam,

I read you, but I'd almost say... don't bother.
Most "passive" equipment now lasts longer than the shelf life of the battery.
Look at your kitchen timer, or your watch.
The only time they drain the battery is when they go "beep"" for some reason, which uses a few hundred milliwatts rather than microwatts.

With current technology, a receiver that listens and only answers to an interrogator (rather than to every whale passing by) will, as I said, die only when the battery dies. Always assuming the battery is designed to continue functioning at the temperatures 4000m down.

Just thought of this while typing, actually :ugh:
What is the temperature 4000m down? And what does that do to the currently used batteries?

CJ

mm43 7th Jan 2010 22:05

@ChristiaanJ

What is the temperature 4000m down?
Around +1 °C

And what does that do to the currently used batteries?
Operating temperature of Lithium batteries -55 to +130 °C (depending on what designed for), but suspect lower temperature will result in slightly lower voltage and current output.

mm43

Sallyann1234 8th Jan 2010 10:52


The boxes would have to only listen say every 15 mins for a few seconds
Microphones are delicate things.
Would the proponents of such a system kindly propose a design for a suitably small, light and low-powered receiver transducer that could function reliably under a seabed pressure of a few tons per square inch?

beachbud 11th Jan 2010 12:15

Captains And Co Pilots
 
Can anyone tell me Air France's history with regard to reducing the number of captains on a long haul flight from two to one? Is this the case? And what about US carriers? BA?

onetrack 11th Jan 2010 14:33

For those who aren't up with underwater recovery ability, the recovery of the remains of AF-447, is most certainly within the realms of possibility.
Bluewater Recoveries have an outstanding record of shipwreck and treasure recovery - aircraft wreckage recovery is only a slight shift in their capabilities.
These people have engineered recovery vessels capable of locating and lifting 200 tons from 6000 metres .. and they have carried out projects whereby long-lost wrecks have been found, and large tonnages have been lifted from great depths in the ocean.
All the initial indications are, that the greatest depth that the remains of AF-447 are at, is around 3850 metres. It's more likely that the actual position is around 3250-3500 metres - quite within the abilities of the BR Company.

Admittedly, many shipwrecks left a decent paper trail to allow some narrowing of the search. A lot didn't, and they were still found by David Mearns and his skilled helpers (HMAS Sydney comes to mind).
AF-447 left some surface wreckage that helps pinpoint the area - Mearns and his associates have all the necessary equipment, to allow further target area narrowing, and searching with robot submarine vehicles at vast depths. All that's needed is the money.

This should be a French-Govt-initiated search, with additional financial assistance from other nations involved in pax losses. The amount required to find the important larger remnants of AF-447 appears to possibly be in the order of US$5-10M. This is piggy-bank money to Govts and nations, particularly when you see what they waste on other fruitless projects.

The Australian Federal Govt, in combination with Australian State Govts, easily found AU$4M to pay Mearns' company to find the Australian WW2 Hospital ship, the Centaur.
Mearns found the wreckage of the Centaur with ease - just as he found the wreck of the HMAS Sydney - a vessel whose location was argued and tossed about, for nearly 67 years. Many wild theories were bandied about as regards the loss and location of the HMAS Sydney, too.
I think I'd be pretty safe in saying, that if the funding was found for Mr Mearns and his operatives, they would relish the chance to find the remains of AF-447 and raise it.

This needs to be done, to put to bed, once and for all, the endless pontification, the endless rumours and finger pointing, and to define the precise reasons for the loss of AF-447. These Govts of the nations involved, as well as Air France, owe this much to those unfortunates who perished in what appears to have been believed to be (by aircraft design people) a nearly impossible event.

Bluewater Recoveries - Blue Water Recoveries are a deep sea shipwreck recovery company

ChristiaanJ 11th Jan 2010 16:20

Thanks, onetrack.

My first question would be "IS there a wreck"?

BWR has been working on shipwrecks. Now those are usually largely in one or two pieces, even if they're associated with a debris field - I expect all of us here are familiar with the Titanic as the classic and most-often described example.

What if there IS NO wreck, but only a widely dispersed debris field?

CJ

Donkey497 11th Jan 2010 17:26

If there's no actual "wreck" as such, just a debris field, it might make things easier to find as a debris field is considerably larger than the craft. :ok:

Where it gives you problems is that you have more individual pieces to pick up and re-assemble to get to the initial cause.:(

I guess tha main thing is to have an active search under way, rather than sit on shore and speculate.

Finn47 11th Jan 2010 19:42

Flight data recovery working group
 
The BEA has formed an international working group to explore all kinds of ideas which would ensure better recovery of recorders and/or data during and after accident events. Most of what has been suggested here is being discussed.

Following the AF447 occurrence as well as other difficult sea recovery operations, the BEA decided to create an international working group called “Flight Data Recovery” in order to look into new technology to safeguard flight data and/or to facilitate the localization and recovery of on-board recorders. Areas such as flight data transmission via satellite as well as new flight recorder or ULB technology have been considered. It was also important to assess the cost and benefits of the possible solutions compared with existing systems. This working group met twice to perform this task.
There´s quite a lot more to read here in this technical report dated Dec 22:

http://www.bea.aero/en/enquetes/flig...nal.report.pdf

JD-EE 12th Jan 2010 00:50

Large masses of ferrous metal may be easier to detect than large masses of composites. But, if they detected wooden vessels with few if any cannons, the picture for AF447 looks nicer.

{^_^}

BreezyDC 12th Jan 2010 02:56

Thanks for the citation, Finn 47.

Impressive for their empirical approach, methodology and processes for evaluating technical feasibility, cost and applicability, as cited in the body of the document and the appendices. Also that this was accomplished in a couple month period.

Razoray 14th Jan 2010 21:06


I think it is terribly important they raise the Titanic... er... AF447
As in the case of the Titanic, there is an experienced crew, following SOP, and then Bam!
Yes, there are eerie similarities between the two tragedy's. Captain Smith and crew were arrogant, speeding ahead into an ice field. They were overly reliant on modern technology and considered thier vessel unsinkable......and Captain Smith was asleep far below decks when the plane....er.....Titanic hit the ice berg....

:suspect:

robertbartsch 14th Jan 2010 22:48

...90 day FDR recommendation is confusing to me. If an A/C goes down in very deep water, would this increase the odds of retrival? On the other hand, it is probably a "cheap" mod that could be done "fast" on existing units.

I'm I correct in assuming that no one has ever tested FDR at the depth where AF447 is suspected to have gone down? ...pressures at those depths must be enormous.

mm43 14th Jan 2010 23:00

@robertbartsch

...pressures at those depths must be enormous.
Nearly 1 atmosphere for every 10 meters, e.g. 4,000m = 397.815atm

mm43

grumpyoldgeek 14th Jan 2010 23:49

One one thing I've often wondered is why the various navies didn't get involved,
using their antisubmarine technology to triangulate the wreckage before the pinger stopped.


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