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-   -   737-500 missing in Indonesia (https://www.pprune.org/rumours-news/637944-737-500-missing-indonesia.html)

sceh 22nd Mar 2021 11:45

still no news on the CVR search?

retired guy 25th Mar 2021 10:13

Dear EXCRABgg
Experience - oh dear. What a misused word I find. I knew a man who retired from the civil service and he was described as a man who had 35 years experience. A soft voice at the back said " He came to work on the first day, and repeated it 10,000 times but never improved." That is the case in so may reports on pilot experience levels. USA 1500 hours experience before CPL. Europe 180. But if the 1500 was crop spraying or "hour building" the 180 at Oxford/Jerez ATO would be more valuable. "The captain had 10k hours before the crash. " Then we find he was in the Soviet Air Force for much of that time doing great things with solo fighter jets which hardly equips you to fly a civil airliner with much use of a level CRM playing field. And so on......... Just at thought that is often missed.

BedakSrewet 25th Mar 2021 10:59

Since the ULB ( of the CVR ) was found, one would guess that the CVR must be around the same area from where the ULB was found.

pineteam 25th Mar 2021 15:09

retired guy

Well said. Could not agree more. :D

DaveReidUK 25th Mar 2021 16:35

It will be in the last place they look ...

etudiant 25th Mar 2021 18:13

The crash site is open ocean and not that shallow, so it may be challenging just to relocate the exact spot where the other bits were recovered. Plus it is a costly exercise, which is surely orphaned in the system.
One wonders whether a reward, say $1MM, would encourage the searchers.

lomapaseo 25th Mar 2021 18:29

Many a plane parked on a remote tarmac will then be missing its CVR

grizzled 25th Mar 2021 19:42

Hahahaha! Yes indeed. One of the first lessons I learned as a naive newcomer to accident investigation in the developing world: Don't offer a reward. For anything. I won't tell the tale here -- and lomapaseo, you likely know the story anyway.

etudiant 25th Mar 2021 23:21

Sigh... I think I understand exactly what you mean.
Even though faking the cockpit audio would not be easy, any such 'discovery' would certainly throw another spanner into the process.
Probably best to keep on searching.

Asturias56 26th Mar 2021 09:56

"The crash site is open ocean"

I'd say open sea rather than ocean and not that far from either land or islands. It isn't that deep. I know the area reasonably well and have dived on some of the islands nearby. The big problem is that the whole area is covered in recently laid down mud from all the rivers in N Java - no hard bottom. Probably the best way would be a very high-res magnetometer survey - but the CVR is tiny in proportion to the volume of the area it could be in

retired guy 26th Mar 2021 11:18

Hi Asturias. I think we are talking about the CVR memory card - the box was found - is that correct? If its a memory card buried in deep mud it going to be some challenge all right.

DaveReidUK 26th Mar 2021 12:56

retired guy

"I think we are talking about the CVR memory card - the box was found - is that correct? If its a memory card buried in deep mud it going to be some challenge all right."

If by "the box" you mean the stainless steel/titanium container that protects the memory modules, then I haven't seen any reports saying that has been found.

lomapaseo 26th Mar 2021 13:50

Can you post a pic with a relative scale of what they are looking for?

DaveReidUK 26th Mar 2021 16:32

This is the FA2100 recorder family (CVR is the one in the background):

https://cimg6.ibsrv.net/gimg/pprune....608e9ba914.jpg

Width of the FDR and CVR is 5.0 inches, so the diameter of the cylindrical memory module shell is just a tad less than that.

EddyCurr 26th Mar 2021 18:04

DaveReidUK posted an image of an intact CVR (& FDR) in P#696

From the following article:Below is an image of one of two CVR sub-components that have been recovered to date. The other piece recovered is the ULB - the polished horizontal cylindrical object mounted in brackets projecting from the side of the Crash Survivable Memory Unit in DaveReidUK's post.

As can been seen below, the CSMU (which in P#681 I suggested is slightly smaller than a stainless steel 1L mini sauce pan that you can probably find any reasonably discerning cook's kitchen cupboard) has been sheared off the top of the CVR housing.

Photo credit: Antara/Muhammad Adimaja

https://cimg5.ibsrv.net/gimg/pprune....f9618c645a.jpg


lomapaseo 26th Mar 2021 19:40

Sorry I'm still confused by the great pix. I don't want to know what has been found I would like a scaled view of what they are still looking for. An artist rendition or photoshop overlay would help

I've never watched one being opened up, all I did was listen to the recordings

infrequentflyer789 26th Mar 2021 20:53

If it helps, this is my attempt at a not-actually-Photoshop overlay:

https://cimg2.ibsrv.net/gimg/pprune....03a0d13471.jpg

For rough scale use the hand, or other posters' suggestions of !L saucepan or just under 5in diameter.

There are repeated posts about looking for "memory card" (or similar) - those are just misleading. If the CSMU has worked as designed then the memory cards will still be sealed inside it, it is finding the unit now it is separated from the chassis and ULB that is the problem. I've never handled one either, so I don't know how much they weigh, but given what they are specified to withstand they won't be exactly light (1kg or slightly more maybe?) - gut feeling says a 1kg round projectile may penetrate whatever it lands on a lot further than that flat chassis.

Chu Chu 26th Mar 2021 21:27

It seems like a reasonably safe assumption that whatever force ripped the CSMU off the chassis didn't drop to zero at the moment of separation.

lomapaseo 26th Mar 2021 21:35

Many Thanks !!! .

being circular in shape helps even if torn off the base. It is probable that a major impact was against the round secion and reacted by the base which was recovered. I would consider it likely that a major aircraft structure hit it when it entered the water and that the cylinder and major aircraft structure were in close proximity together on the bottom. Might even be embedded into each other.

More likely that its tangled in something than buried in mud

Did they bring up all the big pieces that could be wrapped around this cylinder? How about clothing and carpets as well?

grizz I spent sometime going through stuff like this looking for a missing scavenge pump about half its size

EddyCurr 26th Mar 2021 22:17

Here is a link to a document with photos: pgs 3-4 show extraction of circuit boards containing memory chips from the CMSU of a Honeywell 6022 CVR.

The physical outer shape of the 6022's CMSU is somewhat different, but it has similar "circuit boards encapsulated within a thermal barrier substance housed inside a strong enclosure" construction.
NATIONAL TRANSPORTATION SAFETY BOARD
GROUP CHAIRMAN’S FACTUAL REPORT OF INVESTIGATION
DCA19MA086
By Sean Payne


EVENT SUMMARY
Location: Baytown, Texas
Date: February 23, 2019
Aircraft: Boeing 767-375BCF, Registration N1217A
Operator: Atlas Air Cargo, Flight 3591
NTSB Number: DCA19MA086

DaveReidUK 27th Mar 2021 07:31

infrequentflyer789

"If it helps, this is my attempt at a not-actually-Photoshop overlay:"

Yes, thanks for identifying the cylindrical part.

jolihokistix 27th Mar 2021 07:52

It looks somewhat like an oil filter for an ICE engine.

turbidus 27th Mar 2021 14:38


At 16m you can dive with Nitrox40 (oxygen enriched breathing air with less nitrogen) and the ground times will be mainly limited by fatigue and body heat loss.
At 16m or even to 50m...you can dive supplied air however long you want....
We have ROV's that can map an area, with video, sidescan, mag, and sub-bottom profilers...mowing the lawn for weeks...
Most have a recovery arm....

EddyCurr 27th Mar 2021 15:28

turbidus

"Mag"? As in magnetic field detection?

In P#606 I asked "does submersible technology exist that is capable of locating a stainless steel component (which may be made of an SS with properties that are not strongly responsive to magnetic field detection) at some depth below the surface of the sea bed amidst a debris field made up of aluminum and other metallic objects?"

The magnetic properties of stainless steel alloys vary significantly according to elements added to the alloy family. The SS pots in my cupboard are NOT responsive to a magnet, the trim on my vintage car IS responsive.

Asturias56 28th Mar 2021 08:23

Also of course there will be a million small pieces of wreckage in the mud :(

EDLB 28th Mar 2021 11:03


Originally Posted by turbidus (Post 11017406)
At 16m or even to 50m...you can dive supplied air however long you want....

At extended times (think hours) this become saturation dives which need much more support and safety equipment compared to normal open water equipment, since you can not decompress to surfaces pressure in short times. You will need chambers and pressurised living compartments. Problem is the nitrogen saturation of your blood and it will take days for decompression after you are fully saturated.
The homo sapiens physiology is not good adapted for long stays below 10m ( 2000mbar absolute pressure) under water level.

EddyCurr 28th Mar 2021 13:07

The twisted pieces of orange-coloured sheet metal on the tank holding the FDR are most of what was stripped from the top of the CVR enclosure displayed a few posts up the thread. Attachment points for where the CSMU was positioned on the CVR enclosure are visible.

The seemingly intact ULB cylinders on top of the tank - one of which was suspended in brackets protruding from the side of the missing CSMU - look incongruous beside those twisted pieces of sheet metal and the mangled sheet metal CVR housing the pieces were torn from.

https://cimg9.ibsrv.net/gimg/pprune....728d2827c4.png

With so much of the CVR in hand, it is tantalizing to think that the CSMU was nearby, but somehow overlooked.

As lomapaseo intimates, the CSMU might be embedded with other debris. While a thorough search through the artifacts already brought to shore has probably been done once, a second pass with fresh eyes couldn't hurt.

andrasz 29th Mar 2021 08:10

The primary challenge here is the nature of the seafloor rather than anything else. The bottom is not distinct, but consists of a deep layer of fine silt carried to the sea by rivers from the surrounding tropical islands (it is not open ocean, but an enclosed shallow inland sea) which is intermingled with both live and decaying micro-organisms that feed on the nutrients in this silt. The mud thickens as one goes deeper, but the top layer is practically of liquid consistency, any denser object will sink into it. Firm ground is several metres below the top of the mud, and any dense compact object will sink to the bottom. Probably all wreckage that was light enough or large enough to stick out of the mud has already been recovered, now the only way forward is to suck away the mud and search by feel, as visibility is next to zero during this process (and when suction stops, nearby mud flows in to fill the void). If done in a systematic way, this will eventually lead to the recovery of all wreckage, but it is a really tedious slow process.

etudiant 29th Mar 2021 12:03

Who pays for this effort and who manages it?

lomapaseo 29th Mar 2021 13:57

Who do you think should and why?

It seems nobody agrees since there is no law

etudiant 29th Mar 2021 20:08

Think the best candidate would be IATA, because they live and die by the air transport industry. Plus they presumably have a serious interest in minimizing disastrous aviation accidents.
That does not address issues of expertise or funding, which are separate, but there does need to be some entity that handles international crashes effectively.
Perhaps the BEA or the NTSB need to become UN sponsored entities to allow them to take on this role>

EddyCurr 29th Mar 2021 23:12

There's an idea, etudiant.

Here's another. The UN could name the entity the International Civil Aviation Organization, ICAO for short.


Nil by mouth 29th Mar 2021 23:31

andrasz

If these are the conditions on the bottom (sea bed) are as described above, divers searching and finding an item such as the CVR component are pretty remote.
As a certificated advanced enriched air diver just disturbing a muddy,silty bottom with a hand or fin renders visibility to zero.
At 16 metres Nitrox 40 is a little OTT, Nitrox 32 is more than enough to give more bottom time and a quicker safety stop (decompression) on ascent.
Divers aiding suction dredging and filtering would be far more productive than literally groping around in zero visibility feeling for the CVR component.

lomapaseo 30th Mar 2021 01:45

EddyCurr

Well if it's money you want why don't you just go directly to the pot that funds ICAO., maybe that has a slush fund not yet allocated

andrasz 30th Mar 2021 09:12


Originally Posted by Nil by mouth (Post 11018869)
Divers aiding suction dredging and filtering would be far more productive than literally groping around in zero visibility feeling for the CVR component.

I believe that is exactly what is happening, but the divers still need to search by hand for remaining heavier components that are not dislodged by suction.

etudiant 30th Mar 2021 11:46

Which one of the several international aviation agencies actually picks up the tab?
Is it a 'case by case' situation or are there agreed rules?

Icarus2001 30th Mar 2021 12:28

The SAR agency in whose SRR the aircraft is located is responsible for the cost. However if the SEARCH is concluded and there is no RESCUE likely then other factors come in to play. MH 370 for example.

morton 30th Mar 2021 14:35

Ref post 711 - Who pays?

Indonesia has been down this road before. See the salvage section of this.

https://en.wikipedia.org/wiki/Adam_Air_Flight_574

WillowRun 6-3 30th Mar 2021 16:07

I don't believe it's accurate to speak of "several international aviation agencies." There's ICAO. And it's the only game in town.
IATA is a trade association; IFALPA an organized labor entity; ACI an airports industry group, etc.

Annex 13, under which investigations are conducted, itself isn't exactly "law." The Chicago Convention of 1944 is an instrument within international law, but the extent to which any Annex is "law" gets into pedantic territory (and even more so regarding SARPs....).

andrasz 30th Mar 2021 16:26

Regarding the questions referring to the responsibility of the SAR costs, if my rusty memory is correct it was all set out in the original 1944 Chicago Convention (the one that established ICAO) or perhaps some later amendment. Adhering States provide Air Traffic and SAR services to all flights falling under the Convention, and in return they may collect an Air Navigation Charge proportional to the overflown distance modulated by an aircraft weight formula to recover these costs. While purely domestic flights do not fall under the Chicago Convention, most adhering States apply the same rules to domestic traffic too. Same Convention sets out responsibilities for accident investigation, and any related search and recovery costs are bourn by the investigating authority (in principle also funded from the Air Navigation Charge). The picture becomes complicated when a small country (with proportionately small ANC income) needs to fund a major investigation (usually involving a foreign airline), but in this case they have the option to delegate the investigation to another interested party (State of operator or manufacturer).

Of course in real life in most countries the collected charges just get swallowed up by the larger state budget, and there is some moaning involved when the bill is presented for an expensive recovery operation (usually carried out by specialised salvage firms).


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