Rescue 116 Crash at Blackrock, Co Mayo(Mod note in post 1)

MadYaker · 26-03-2017 09:22PM

Now that they have the flight recorders are they only interested the fuselage because they think the bodies of the other crew members might be in it? Or if the bodies were found elsewhere would they still be trying to get the chopper out of the ocean?

Mech1 · 26-03-2017 09:30PM

The wreck could still be needed to confirm cause of accident, say it was a exploding oxygen bottle or something that caused it, that wouldnt be recorded on black box data.

Esel · 26-03-2017 09:32PM

As said above, they will try to get as much of the wreckage as possible to help in the investigation.

MadYaker · 26-03-2017 09:35PM

I'd say they'd be reluctant to try a lift until they are 100% certain that there aren't any more bodies in the fuselage also.

Gaoth Laidir · 26-03-2017 09:42PM

From fluid mechanics, pulling a mass through water has the effect of basically doubling its weight. The water inside it wouldn't add extra weight to it as the fuselage's damage will allow the water to escape.

Airbags is the best (and I would say only) method of lifting it for now. Best of luck to them.

vicwatson · 26-03-2017 09:50PM

Skuxx wrote: »

Just mentioned on RTE news that they plan to put airbags under it tomorrow to try and lift it and look for crew members underneath, if no sign then plan to broaden the search area. They mentioned parts of the wreckage have been found near Killybegs today, goes to show the strengthsof the currents!

Pat McGrath said the search area would be the size of a football pitch.

Irish Steve · 26-03-2017 09:59PM

The first priority is the recovery of the remains of the rest of the crew. For all the reasons detailed above, that is going to be a much more complex operation than had been anticipated.

After that, a lot will depend on what information comes out of the FDR, there is the very real possibility that AAIU will want as much as possible of the airframe to fill any gaps in the information they have, and in certain circumstances, it may be essential to recover some parts of the aircraft to allow AAIU to determine the sequence of events that happened. If they don't have the right equipment to do that at present, then they will get whatever is needed, as it is vital to get the right information about what happened, to make sure that it can't happen again any time soon for the same reason.

TomOnBoard · 27-03-2017 02:34AM

Call me Al wrote: »

The reporter mentioned that in the past 24 hours wreckage has been recovered as far north as Killybegs.

According to the Irish Times, quoting Belmullet Gardai, wreckage was found even further North at Portnoo. http://www.irishtimes.com/news/ireland/irish-news/coast-guard-helicopter-debris-found-on-donegal-coast-1.3025647

The thing is, the whole target area for shoreline search for wreckage will now become massively greater, as the currents that will have brought it as far as Portnoo will, once past Arranmore, next hit major coastline on the Western Isles of Scotland.

bronn · 27-03-2017 02:46AM

TomOnBoard wrote: »

According to the Irish Times, quoting Belmullet Gardai, wreckage was found even further North at Portnoo.

Jesus, Portnoo already?

Diving in those sea conditions and currents must be utterly exhausting both mentally and physically. The dedication and super-human effort being given by all involved in this search & recovery is nothing short of heroic. Fair play to them all and I hope they all stay safe and watch out for each other.

Gaoth Laidir · 27-03-2017 09:31AM

Waves and currents in the area this morning. From yr.no

Waves

Currents

TheChizler · 27-03-2017 12:30PM

I've just found out that I'm related to the immediate family of one of the crew members, and while I've never met them, I have family who would have known them well in the past. It just makes you realise Ireland is so small, and gives me an extra appreciation of the sensitivity and professionalism Boards mods and admin have exhibited on this thread.

Call me Al · 27-03-2017 12:39PM

Regarding the blackbox analysis, will this carry data relating to a serious sudden failure such as a gearbox malfunction?
Thanks

gahsux · 27-03-2017 12:42PM

mulbot wrote: »

Good to hear-I think that's equivalent to my PADI Divemaster? Doesn't look like they are on re-breathers with their short bottom times,maybe to decompress quicker? Is it likely the ROV has done alot of the work already?

Does anyone know why the divers have only 8-10 minutes at the wreck site? From my basic diving experience, 40m is around the limit for recreational diving and I would expect professional divers would have equipment and techniques to operate for a longer time at this depth.

irishgeo · 27-03-2017 12:44PM

https://earth.nullschool.net/#current/ocean/surface/currents/orthographic=-12.65,54.27,3000

map of current ocean currents.

scuby · 27-03-2017 01:04PM

gahsux wrote:

Does anyone know why the divers have only 8-10 minutes at the wreck site? From my basic diving experience, 40m is around the limit for recreational diving and I would expect professional divers would have equipment and techniques to operate for a longer time at this depth.

They would have to go into decompression chambers, reducing the turn around time, until they can dive again

Kerrydude1981 · 27-03-2017 01:08PM

scuby wrote: »

They would have to go into decompression chambers, reducing the turn around time, until they can dive again

I was reading through the thread during the weekend,just wondering how long would the turn around/recovery time be for the divers until they can dive again?

gahsux · 27-03-2017 01:21PM

Kerrydude1981 wrote: »

I was reading through the thread during the weekend,just wondering how long would the turn around/recovery time be for the divers until they can dive again?

scuby wrote: »

They would have to go into decompression chambers, reducing the turn around time, until they can dive again

So is it a shortage of divers then? Why can't they can't have one team decompressing while another works?

uck51js9zml2yt · 27-03-2017 01:23PM

gahsux wrote: »

So is it a shortage of divers then? Why can't they can't have one team decompressing while another works?

As with everything,there is a limited number of divers with the skill needed for this recovery.
They are limited in the amount of Dives they can do.

ectoraige · 27-03-2017 01:27PM

gahsux wrote: »

Does anyone know why the divers have only 8-10 minutes at the wreck site? From my basic diving experience, 40m is around the limit for recreational diving and I would expect professional divers would have equipment and techniques to operate for a longer time at this depth.

There's a number of factors, but the main reason will be diver safety. By limiting their time at that depth, the divers can make a continuous ascent to the surface over a period of about two to three minutes. If the divers remained at that depth for any longer they would have to take decompression stops during their ascent. This makes any equipment failures more hazardous. Given the unpredictability of the technical work you need to anticipate things such as the risk of lines getting snagged on debris. From the divers I've known, it's slow and tedious work where rushing never does anybody any good.

It also allows them to return for a second dive sooner. I'm speculating now, (eek!) but I assume they work in teams so the first team will go down, carry out their planned work, and return to brief the next team. The second team will then plan the next stage of work, and gather any extra equipment or information needed before making their dive. This then cycles through until enough time has passed before it is safe for the first team to make another dive. The length of rest needed will depend on the gas mixtures used and the exact profile of their dive, but it could be every four to six hours, I'm wide open to correction on this.

ted1 · 27-03-2017 01:29PM

scuby wrote: »

They would have to go into decompression chambers, reducing the turn around time, until they can dive again

If they used rebreathers can't they do away with the decompression chamber. Or significantly reduce the decompression time

sentient_6 · 27-03-2017 01:48PM

Quick someone ring the Navy and tell them there's a thread on boards with lads that know better than them. FFS.

ectoraige · 27-03-2017 01:55PM

ted1 wrote: »

If they used rebreathers can't they do away with the decompression chamber. Or significantly reduce the decompression time

Rebreathers can extend the working time, but also introduce extra points of failure. The wreckage is still in relatively shallow water allowing them to use more trusted methods. I expect if it have been much deeper then they would be using a different strategy, but the last thing anybody wants is a fatality during a recovery operation. If it means it takes a few extra days, so be it.

MadYaker · 27-03-2017 02:10PM

sentient_6 wrote: »

Quick someone ring the Navy and tell them there's a thread on boards with lads that know better than them. FFS.

Ah come on, there's no need to be rude. People are just trying to educate themselves about something they know nothing about.

sentient_6 · 27-03-2017 02:17PM

MadYaker wrote: »

Ah come on, there's no need to be rude. People are just trying to educate themselves about something they know nothing about.

I probably should have quoted this post above mine specifically:

ted1 wrote: »

If they used rebreathers can't they do away with the decompression chamber. Or significantly reduce the decompression time

Sounds like someone making a fairly to the point statement to me.

January · 27-03-2017 02:19PM

Looks more like a question to me, they'd have said 'they could use' if it was a statement.

PCX · 27-03-2017 02:25PM

Diving that requires decompression stops is riskier than staying inside of no deco limits.

Decompression stops would require the divers to stop on the way back up and stay in situ for considerable lengths of time at depths a few meters down from the surface. I imagine that the swells and currents in the area and being so close to the rocks make this far too difficult to be risked.

Hats off to the divers doing this demanding and risky job.

ted1 · 27-03-2017 02:50PM

sentient_6 wrote: »

I probably should have quoted this post above mine specifically:

Sounds like someone making a fairly to the point statement to me.

No it was a question, can't they as oppose to they can.

spaceHopper · 27-03-2017 03:01PM

The divers have to work with in limits of safety and what their bodies can take too.
Lets say are 40m you could safely stay down 20 mins, then they will hafl that to 10 mins, this give them margin for error if something goes wrong and they need to stay down longer.
The swell at the surface will be a problem too, if it's anyway big then they won't be able to do a safety decompression stop at say about 10M they'd be bobbing around in the swell.
Then if they all says down longer they could potentially have to go into the decompression chamber for a number of hours. Once it's in use they will have to stop all diving because they can't stop it mid way through to let somebody else in. And chambers aren't something you keep lying around there is probably only one.

By doing short dives they reduce the risk and keep the possibility of diving open, they probably get more done too.

youtheman · 27-03-2017 03:09PM

Better option would be to use Saturation Divers (from a Dive Support Vessel). The vessel would be D.P. (Dynamic Position), and would be able to operate in fairly extreme weather. And you would have divers operating at the work site 24 hours a day, for up to a few weeks on end. Unfortunately, you'd have to get one from the North Sea, and would cost a few million euros for the complete operation.

Coil Kilcrea · 27-03-2017 03:18PM

TheChizler wrote: »

I've just found out that I'm related to the immediate family of one of the crew members, and while I've never met them, I have family who would have known them well in the past. It just makes you realise Ireland is so small, and gives me an extra appreciation of the sensitivity and professionalism Boards mods and admin have exhibited on this thread.

TheChizler, we're a small tribe who stick together when the going gets tough. Profound sympathies and admiration.

Rescue 116 Crash at Blackrock, Co Mayo(Mod note in post 1)

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