Update re search for CVR memory module (CSMU)
.

It's still early days.

SJ-182
..
AF447
.

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. So it will be more the water surface conditions and temperatures which will determine the possible dive times. Since the small CVR unit can be deep in the mud, it can take a long time until they find it. They might at some time change to the typical gold miners solution with water and dirt pumps and separation on the surface.

Vilas,
Pilots are in the cockpit because their skills are supposed to be better than computers.
That's an interesting point of view, but not one I'd agree with. I'm not disagreeing that automation technology has now advanced to a level that gives that view credibility, however, I'm not sure that automation could cope with all the potential variables.

Maybe we're looking at this the wrong way, perhaps we should be looking to integrate the human factor into the automatics.

@Flying Clog #652, I agree. The most fundamental, the most basic thing a pilot must do is roll the aircraft wings level and pitch to level flight. And be able to do this instinctively, correctly, and by reference to just an attitude indicator, nothing else.

You can also do it with only an old fashioned turn and slip indicator and the VSI and ASI.

.
The 2021.02.15 briefing that included remarks about new provisions for a diving chamber and ambulances (#610) prompted me to wonder whether these were proactive or reactive measures to address dive team needs.

.
I asked earlier (#606) about contingencies for locating the CVR memory module when the ULB has been dislodged from the prominent external mounting brackets on the CSMU. There were no replies.

So close, yet ...

Edit: #606, not #667 re question about contingencies for locating CVR memory module.

The CVR recovery from AF447 has been mentioned a couple of times. It seems that its memory unit had remained in the shiny orange box. With the memory having gone AWOL
in the present case, it adds a different measure of difficulty to the search, offsetting the depth advantage somewhat. I have not noticed any published estimations of the chances
that the memory unit in its bare protective sleeve might get carried away by currents, in which case there is yet more added difficulty.

Euclideanplane

"I have not noticed any published estimations of the chances that the memory unit in its bare protective sleeve might get carried away by currents, in which case there is yet more added difficulty."

It's in a stainless steel shell. The most likely direction that it has travelled is downwards, into the mud, rather than being swept away by currents.

Even on normal compressed air the non decompression limit is 60minutes or so.

Whtever gives you that idea? I know the FMS will intercept and fly an ILS with 20 knots of crosswind better than I will. The reason we are there is that we are adaptable, flexible and can react to unusual situations and make rational decisions.

In #227 DaveReidUK wrote: "Found a video of the recovered CVR chassis from yesterday, which confirms it's an L3 (originally Fairchild) FA2100." A video in the post reveals the state of the FDR and CVR components found at the time.

The FA2100 can be viewed at the L3Harris website. The cylindrical drum in the foreground is the stainless steel "Crash Survivable Memory Unit". The orange outer housing with the reflective tape forms the protective shell for the CSMU - this is what divers will be searching for.

If the outer housing of the drum is compromised or separated from the contents (refractory material for heat protection and circuit boards bearing the solid state memory chips), I imagine that prospects for data recovery may be hampered.

blind pew

According to the initial accident report the Indonesian F/O had almost 5000 hours on the 737. Considering that in Europe LCCs generally only ask for about 4000 hrs total time for command upgrade I wouldn’t say this f/o had “limited experience”.

Re Experience of F/O in accidents ; In the last 20 years it has been quite often that its was the low time F/O that had it right and not the experienced 10.000h captain .
As to some European LCC ( or African for that matter) being on the right seat of a 320 or 737 with 250h TT is not that unusual .

Experience (funny that) has taught me that it's often the new person on type, either seat, who is more recently through the type rating who can remember some obscure and important fact rather than the old hand. Worth remembering when you're sat next to a brand new shiny F/O. They might lack raw handling skills and have the energy management you do, but their recall of limitations and specifics is probably better than yours!

Update re search for CVR memory module (CSMU)

Excerpts from a briefing 2021.03.03:
.

Or even less.

Can someone clarify the “mud suction” process? Assume mud removal makes for easier search, but is the mud/other debris suctioned up also examined? I thought I’d read that the actual missing bit of the CVR was quite small....?

I imagine they're talking about something like this:


The removed mud is dropped into a series of sieves to examine the material removed.

Joejosh999

The following physical dimensions are taken from a page on the L3Harris website for the FA2100 series of L3Harris Cockpit and Data Recorders:
..
In an accompanying image, the CSMU is the drum-shaped component of the FA2100 series assembly. From that image, my reckoning is that the dimension of the CSMU portion is approximately 100mm OD x 100mm (4" x 4") tall.

For perspective, look for a 1L / 1 Qt deep stainless steel mini sauce pan in your kitchen cupboard.

If my size estimate is correct, then the CSMU component that KNKT is searching for is somewhat smaller in diameter and height than such a sauce pan.

Thanks Eddy. Doesn’t sound too big. Can’t be easy to find....