'Contact lost' with Malaysia Airlines plane

[drunkenmaster]

Good question.

I'm not even sure of the location of the flight recorder in the plane. Is it in the cockpit?

Plane hitting the ocean, might be completely on it's own, or in whatever piece of the plane it was in before I guess.

Seems the Air France one was robotic submarine retrieval? Not sure how long that takes once you get the location part somewhat sorted. I think the Air France issue was how long it took to find it no idea how long the actual retrieval took.

 

[ThundyCat]

Well the Titanic was over two miles down and they sent unmanned submersibles into the wreck....so hopefully they will be able to do the same with MH370.

 

[Hyburnate]

Awesome, lets hope its the flight data recorder or the cockpit voice recorder, although surely the former would be better?

 

[drunkenmaster]

Just reading the wiki on the 447 recovery. When they finally found the crash site and then located the black boxes they got them up pretty quickly. Sounds like the first dives were made on April the 26th, the found the memory box on the 1st may and had them both onboard and en route to be looked at by the 7th.

At that depth(about 4000ft I think) it's pretty impressive that they basically got down there, looked around and retrieved both boxes in basically less than two weeks.

 

[Tuppy_Glossop]

I understand the CVR has a limited amount of memory so it overwrites itself. It will only have the most recent x hours. The FDR should have data for the entire journey.

 

[drunkenmaster]

http://maps.ngdc.noaa.gov/viewers/bathymetry/

If i'm looking at the right area 25 by 101, then(when you zoom in there is a bit more gradient detail) it looks like there is a low area included which is 5000ft depth, it misses the highest point which is 1600ft and there is a large area in between those heights which doesn't give an indication of the depth but you presume is significantly lower than 1600 and higher than 5000 depth.

 

[Lysander]

I understand the CVR has a limited amount of memory so it overwrites itself. It will only have the most recent x hours. The FDR should have data for the entire journey.

It has two hours of recording.

However if the pilot is on his own in the cockpit it will be little but silence and warning alarms.

 

[Tuppy_Glossop]

Zoomable Indian Ocean map

If it's in the Wharton Basin it could be as deep as 6000m.

 

[sniffy]

Brilliant news if this proves fruitful.

Awesome, lets hope its the flight data recorder or the cockpit voice recorder, although surely the former would be better?

I believe it only records within the cockpit for two hours then it starts overwriting old data. In this instance I imagine the main events took place long before the actual crash so not sure how useful it will be.

 

[Tefal]

Pressurising the cargo hold seems like bad design anyway, if there was no oxygen a fire would never start.

you know planes are tube shaped?

ever noticed most pressure vessels are too?


try and think why depressurizing the cargo hold but keeping the cabin pressurized might be a massive engineering challenge

 

[Hyburnate]

Brilliant news if this proves fruitful.



I believe it only records within the cockpit for two hours then it starts overwriting old data. In this instance I imagine the main events took place long before the actual crash so not sure how useful it will be.

It's only NTSB's recommendation to be 2hrs :/

e; But as Tefal says about pressurisation, it's not something we're able to do. Currently in the case of decompression of the cago hold there are vents that will close to keep the cabin pressurise but IIRC these don't work for too long.

 

[sniffy]

It's only NTSB's recommendation to be 2hrs :/

Well the events surrounding this accident are quite unique. From their prospective it's about striking a balance between keeping things as simple as possible whilst still having the level of sophistication required for the data to be useful. In most instances two hours is perfectly adequate so I guess it makes sense although irritating when the exceptions rear their head.

 

[dannyjo22]

Currently in the case of decompression of the cago hold there are vents that will close to keep the cabin pressurise but IIRC these don't work for too long.

They are to equalise the pressure so the floor doesn't collapse. They don't close on any I have worked on, the panel/seal blows.

This will explain to you better than I can type it...

http://lessonslearned.faa.gov/ll_main.cfm?TabID=4&LLID=18&LLTypeID=2

 

[Hyburnate]

They are to equalise the pressure so the floor doesn't collapse. They don't close on any I have worked on, the panel/seal blows.

This will explain to you better than I can type it...

http://lessonslearned.faa.gov/ll_main.cfm?TabID=4&LLID=18&LLTypeID=2

Is that your way of saying they don't work properly?

Because wasn't there another accident caused by the cargo hold opening because of some reason and it was ruled that there should be more vents?

 

[drunkenmaster]

He's saying it's the other way around. They are closed in normal use and they blow open if the cargo hold de-pressurises. If the cargo hold goes and the top half seals then the pressure difference between the top and bottom would cause massive difference between top/bottom half of tube and it would I presume, collapse. By releasing the pressure in the passenger cabin you drastically reduce the difference in pressure between the top and bottom half of the tube. So I presume in the other accident the cargo de-pressurises and there weren't enough vents to equalise pressure quickly enough and something would have failed.

 

[MOOGLEYS]

It's only NTSB's recommendation to be 2hrs :/

e; But as Tefal says about pressurisation, it's not something we're able to do. Currently in the case of decompression of the cago hold there are vents that will close to keep the cabin pressurise but IIRC these don't work for too long.

The vents are to stop the floor collapsing. A couple of crashes were caused by the passenger floor being sucked down and severing control lines and cabling that runs through the floor. They do not stop the loss of pressure just allow the pressure to be lost equally around the pressurised cabin.

 

[drunkenmaster]

The vents are to stop the floor collapsing. A couple of crashes were caused by the passenger floor being sucked down and severing control lines and cabling that runs through the floor. They do not stop the loss of pressure just allow the pressure to be lost equally around the pressurised cabin.

I was wondering where the damage was, I assumed the floor but wondered more like was it internal damage IE floor/cables or can a failure in the cabin floor cause the tube to fail. Or can it do both?

 

[Tefal]

It's only NTSB's recommendation to be 2hrs :/

e; But as Tefal says about pressurisation, it's not something we're able to do. Currently in the case of decompression of the cago hold there are vents that will close to keep the cabin pressurise but IIRC these don't work for too long.

other way around they let the cabin pressure out not keep it in. saves the high pressure in the cabin blasting through the floor as it's no longer supported by high pressure in the cargo hold.

 

[MOOGLEYS]

I was wondering where the damage was, I assumed the floor but wondered more like was it internal damage IE floor/cables or can a failure in the cabin floor cause the tube to fail. Or can it do both?

Any rapid de pressurisation is going to cause considerable failure of the Aircraft structure. The idea of the floor venting is to try and protect critical cabling and hydraulic lines running through these areas so hopefully maintaining as much control of the aircraft as possible.

 

[Hyburnate]

Ahh damn I wish my mind would remember things