MH370 Malaysia Airlines B772 Missing Enroute KUL-PEK Part 15

Finn350 · Wed Mar 12, 2014 6:56 am

Quoting kmot (Reply 98):
Here in lies the problem. I can't tell where I have spotted it. And if they have in fact found a raft, then this is mute

The raft is most likely from a ship, not an aircraft. But we will learn shortly, as we have a good photograph of the raft.

giopan1975 · Wed Mar 12, 2014 6:57 am

Quoting mandala499 (Reply 68):
Question: Who's going to pay for it?

OK then it is all about money and who cares about locating 200+ missed people (dead or alive) in the first seconds of communication loss?

Anyway, how many airplane orders has Boeing been missing during these 5 days of mystery? How much money has evaporated by stocks of related companies falling? How many people will develop fear of flying after such extensive global media coverage of the event? We are in 2014 and a super dooper high tech huge airplane just dissapears and noone is having a clue about what has happened.

Again you will argue that people do not have any alternative, they will keep on using the airplane and most of this story will be forgotten after 6 months, profitability will return to wished levels.

XFSUgimpLB41X · Wed Mar 12, 2014 6:59 am

Quoting kmot (Reply 83):
I have updated the map and put the red circle to the left of what I am describing.

http://www.tomnod.com/nod/challenge/.../4894

It does look like an airplane, but look at the scale and compare it to the object. Aft of the "wing" is longer than the 777-200 is in total length.

hamiltondaniel · Wed Mar 12, 2014 7:01 am

Quoting XFSUgimpLB41X (Reply 102):
It does look like an airplane, but look at the scale and compare it to the object. Aft of the "wing" is longer than the 777-200 is in total length.

Looking again I am back to thinking it's a compression artifact, but if not:

The "line" of the aft portion is offset slightly from perpendicular to the wing box (if we assume that those are wings), suggesting the tail has broken off and may be lying separately from the wings.

In fact, the two smaller patches down and left seem almost triangular, like stabilizers.

But that's really, really stretching it. What would a submerged white aircraft look like in these kinds of waters? Grayish-blue, I guess, but man.

Note how whatever it is is conveniently in the middle of a band of "smoother" compression within the left-to-right gradient in that image. I don't know enough about compression algorithms of satellite imagery to go beyond noting it, but it is interesting.

[Edited 2014-03-12 00:06:26]

woodentom · Wed Mar 12, 2014 7:03 am

Finding a raft sounds very positive but am amazed it has been found so close to KL. The currents maybe strong in the area.

Also from reading the posts and understanding how strange the Malaysian authorities have been, a sceptical person could think the raft has been planted in the sea in order to be found.........

Do rafts have individual codes to each plane so we know for sure it was from the 777??

Enobar · Wed Mar 12, 2014 7:03 am

Quoting Finn350 (Reply 100):
The raft is most likely from a ship, not an aircraft. But we will learn shortly, as we have a good photograph of the raft.

You think its from a ship? I think it looks like it says "Boeing" on that red sticker.. but then again if it did say Boeing, wouldn't you take a clear photo of it if you were the fisherman?

gr325 · Wed Mar 12, 2014 7:04 am

Well according to the text in the article it says Boarding.

Enobar · Wed Mar 12, 2014 7:08 am

Quoting gr325 (Reply 106 Well according to the text in the article it says Boarding. ):

Oh, I skipped right over the headline... urgh. Does anyone have any knowledge of what kind of information is printed on the life rafts? I can't imagine they would have "Boarding" written on them.. unless that donates the side which it is boarded from (i.e. the part which sits against the aircraft).

If it is from the plane, is it likely to have floated free without having been accessed by passengers? Surely it could be a sign that there are (or were) survivors?

[Edited 2014-03-12 00:10:00]

jetblueguy22 · Wed Mar 12, 2014 7:10 am

Quoting Enobar (Reply 105):
You think its from a ship? I think it looks like it says "Boeing" on that red sticker.. but then again if it did say Boeing, wouldn't you take a clear photo of it if you were the fisherman?

Do the rafts actually say Boeing though? I would think Boeing wouldn't want to put their logo on it. Not exactly the best PR after a crash to see a bunch of liferafts floating around with Boeing plastered across them. I would expect them to say Goodrich or whoever made them.
Pat

PhilV · Wed Mar 12, 2014 7:10 am

Something from Vung Tau region again.

http://twitpic.com/dy1qmm

Thought it was ruled out.. Maybe fake?

rwessel · Wed Mar 12, 2014 7:11 am

Quoting Starlionblue (Reply 18):
Of course the issue is that without electrics you would have no instruments beyond the whiskey compass. At night over the ocean that makes having the flight controls somewhat moot since you have no way of orienting yourself.

The standby instruments have their own battery, do they not? Certainly that's a standard feature on the standbys on smaller aircraft.

hamiltondaniel · Wed Mar 12, 2014 7:16 am

Quoting hamiltondaniel (Reply 103):
Looking again I am back to thinking it's a compression artifact, but if not:

The "line" of the aft portion is offset slightly from perpendicular to the wing box (if we assume that those are wings), suggesting the tail has broken off and may be lying separately from the wings.

In fact, the two smaller patches down and left seem almost triangular, like stabilizers.

In grid 1594, so ~.5mi SE of the object or whatever discussed above in grid 4894, seems to be a slick of some kind.

http://www.tomnod.com/nod/challenge/malaysiaairsar2014/map/1594

http://www.tomnod.com/nod/challenge/malaysiaairsar2014/map/4894

Edit: Nevermind. A different sort of artifact from the shadows of clouds on the water, which turn yellowish-green in this imagery.

[Edited 2014-03-12 00:21:41]

[Edited 2014-03-12 00:22:01]

rwessel · Wed Mar 12, 2014 7:17 am

Quoting hamiltondaniel (Reply 103):
Do rafts have individual codes to each plane so we know for sure it was from the 777??

A certified raft would have a serial number, and the airline should know which serial number rafts are on which aircraft.

phantomx18 · Wed Mar 12, 2014 7:17 am

Quoting Enobar (Reply 107):

From searching pictures on the internet, it appears that airplane life rafts do have the words "Boarding" on them to show survivors which side has the opening to climb into. But I am assuming that a raft that came off a ship would have the same wording, so this is not conclusive, although it might be the first break through in this mystery.

Enobar · Wed Mar 12, 2014 7:17 am

Quoting jetblueguy22 (Reply 108):
Do the rafts actually say Boeing though? I would think Boeing wouldn't want to put their logo on it. Not exactly the best PR after a crash to see a bunch of liferafts floating around with Boeing plastered across them. I would expect them to say Goodrich or whoever made them.
Pat

I am inclined to agree with you - It is probably not the worlds best PR to have your logo all over something like a life raft.. but on the other hand, I wouldn't have been surprised for it to have "Boeing 777-200" written on it as a means to identify the correct equipment being installed onto aircraft. I would assume that somewhere it would have an indication of what aircraft it belongs to, though perhaps not so large.

Also, if that was discovered yesterday, surely it has been verified/ruled out by now..

haynflyer · Wed Mar 12, 2014 7:22 am

Quoting Enobar (Reply 107):
I can't imagine they would have "Boarding" written on them.. unless that donates the side which it is boarded from (i.e. the part which sits against the aircraft).

Here's a picture of a life raft. There is the word "Boarding" to indicate where to board.

http://www.raftservice.com/aviation/eam-rafts-t-12.php

While this may not be Boeing life raft nor one that could be used on a ship, yes, they do he word "Boarding" on them.

Unbelievable that they let it get away! But then again, par for the course here.....

Coal · Wed Mar 12, 2014 7:22 am

"However, a Kuala Linggi MMEA spokesman said the raft sunk into the sea while they were trying to bring the raft onboard."

Cheers
Coal

Starlionblue · Wed Mar 12, 2014 7:23 am

Quoting Enobar (Reply 55):
Is this article from CNN accurate?

Quoting flyenthu (Reply 53):
Just saw this on CNN. Quite an interesting take:

http://us.cnn.com/2014/03/12/world/a...der-explainer/index.html?hpt=hp_t1

Because if so, I refer to my original question which I asked about why ACARS doesn't transmit a GPS location. Starlionblue replied (and I thank you for your input, but want to follow up)

Because you don't expect to need ACARS to send a position. It is primarily a maintenance system. The AF447 thing was purely fortuitous in context. You already have multiple ways of communicating and it is rather unlikely that they will all fail. Say the pilots are incapacitated, then the transponder would still be active. If the transponder breaks I'm pretty sure airliners have a second one, plus all the radios. Barring foul play (pulling all the breakers), if you're in a situation where absolutely none of that is working, the situation is probably so catastrophic an automated ACARS message won't do anything to save lives.
- Transponder. 2x
- VHF radio. 2-3x
- HF radio. 2x
- Datalink messaging in some cases.
- Satphone in some cases.
- If you are in visual range, you can signal with aircraft lights and receive from a light gun.

See also below.

Quoting Enobar (Reply 55):
Quoting Starlionblue (Reply 36):
There is already a system to determine location: the transponder.

From what i understand from that CNN article the transponder does not send out the aircrafts location per say, rather it only identifies itself when it is on ATC radar systems. So the difference between the transponder and ACARS actively sending GPS coordinates would be that you would still have a location fix on the plane when it is out of range of ATC.

Am I misinterpreting the article? (Or is CNN wrong?). If my understanding is correct, wouldn't it still be useful to have ACARS broadcasting GPS locations with its other information?

CNN article is correct but it only talks about Mode A (code) and Mode C (pressure altitude). A basic transponder like you'd find in a Cessna 172. A bit annoying because it doesn't really help us much with this event.

Airliner transponders do much more than that. In simple terms, with Mode S, transponders can send out position, heading, speed and gobs of other information. Most of the information you see on FlightRadar24 would be blank without Mode S.

Quoting mandala499 (Reply 60):
Quoting Starlionblue (Reply 20):
In the case of 777, 320, 330-340 you end up in what is called manual reversion.

Manual reversion is only there in terms of total systems failure ie: the HYD AND ELEC systems are unpowered. The 737 has manual reversion... 777, 320, 330, 340, 767, 747 do not.

Thx for clarifying.

[Edited 2014-03-12 00:29:58]

phantomx18 · Wed Mar 12, 2014 7:25 am

Quoting haynflyer (Reply 116):

Apparently fishermen were better equipped to hold on to that raft than SAR crew was. . .geez, this would make for great comedy if it wasn't such a tragic situation.

Starlionblue · Wed Mar 12, 2014 7:26 am

Question about Tomnod. I get the Tomnod logo and then a big blank grey-blue square. No controls or imagery. Any ideas?

Quoting rwessel (Reply 110):

Quoting Starlionblue (Reply 18):
Of course the issue is that without electrics you would have no instruments beyond the whiskey compass. At night over the ocean that makes having the flight controls somewhat moot since you have no way of orienting yourself.

The standby instruments have their own battery, do they not? Certainly that's a standard feature on the standbys on smaller aircraft.

Hitting head on desk now. Must check books in my shelf before posting. Yes I think you are right. Ok but if it is "no electrics at all" we have to fail them too.

hamiltondaniel · Wed Mar 12, 2014 7:27 am

http://www.rfd.co.nz/products/marine...-liferafts/dsb-lr07,-lr-97rsr.aspx

These look closer to the raft in the photo (black and orange, rather than yellow, as I understood aviation rafts to be).

Unfortunately listed as "marine" liferafts.

laxboeingman · Wed Mar 12, 2014 7:28 am

I am sorry, but I have been busy with school all day. I am sure I would have heard, though, but just in case I am going to ask: Did rescuers find anything?

Starlionblue · Wed Mar 12, 2014 7:30 am

Quoting laxboeingman (Reply 122):
I am sorry, but I have been busy with school all day. I am sure I would have heard, though, but just in case I am going to ask: Did rescuers find anything?

Zippo except maybe that raft.

[Edited 2014-03-12 00:32:08]

hamiltondaniel · Wed Mar 12, 2014 7:31 am

Quoting laxboeingman (Reply 122):

I am sorry, but I have been busy with school all day. I am sure I would have heard, though, but just in case I am going to ask: Did rescuers find anything?

A raft, that promptly sank before they identified it.

You can't make this up....

laxboeingman · Wed Mar 12, 2014 7:32 am

Quoting Starlionblue (Reply 123):
Zippo.

OK, thank you and for all of your help in the previous threads as well. That is terrible and unbelievable. Didn't we have some things recovered from AF447 by this point.

laxboeingman · Wed Mar 12, 2014 7:33 am

Quoting hamiltondaniel (Reply 124):
A raft, that promptly sank before they identified it.

You can't make this up....

That is bizarre. How did they even know it was a raft and how does a life raft just sink, esp. one used on a long haul airliner.

hamiltondaniel · Wed Mar 12, 2014 7:35 am

Quoting laxboeingman (Reply 126):
That is bizarre. How did they even know it was a raft and how does a life raft just sink, esp. one used on a long haul airliner.

Fishermen grabbed it, photographed it, and waited for SAR. SAR lost it somehow when they got there. SE of Kuala Lumpur, so way outside any of the search areas.

http://www.nst.com.my/latest/font-co...en-find-life-raft-near-pd-1.509222

Starlionblue · Wed Mar 12, 2014 7:35 am

Quoting laxboeingman (Reply 126):
Quoting hamiltondaniel (Reply 124):
A raft, that promptly sank before they identified it.

You can't make this up....

That is bizarre. How did they even know it was a raft and how does a life raft just sink, esp. one used on a long haul airliner.

If this is the raft, then at least there are pics. http://www.nst.com.my/latest/font-co...en-find-life-raft-near-pd-1.509222

Regarding sinking, the bladders could have been waterlogged.

Enobar · Wed Mar 12, 2014 7:37 am

Quoting phantomx18 (Reply 119):
Apparently fishermen were better equipped to hold on to that raft than SAR crew was. . .geez, this would make for great comedy if it wasn't such a tragic situation.

This is bound to be met with a fresh wave of cries of "coverup". How could the absolute muppets running the SAR operation allow what could be the first break in the investigation literally slip out of their hands..

Also,

Quoting Starlionblue (Reply 118):
CNN article is correct but it only talks about Mode A (code) and Mode C (pressure altitude). A basic transponder like you'd find in a Cessna 172. A bit annoying because it doesn't really help us much with this event.

Airliner transponders do much more than that. In simple terms, with Mode S, transponders can send out position, heading, speed and gobs of other information. Most of the information you see on FlightRadar24 would be blank without Mode S.

Thanks for the clarification. Interestingly enough you say that it would be unlikely that all those methods would fail, yet we seem to be looking at that very situation (barring human intervention in turning it off..). I bring this up not to argue, but because I'm wondering if there is now the possibility that the electrical failures were so severe that the black boxes could have been knocked out too? Is that possible - i seem to recall that in some previous accidents at least the CVR has been disabled (though my memory fails to bring a specific one to mind).

Also, do modern data/voice recorders operate for longer than they used to? didn't they once only record 30 minutes or so on a loop?

laxboeingman · Wed Mar 12, 2014 7:39 am

Quoting hamiltondaniel (Reply 127):
Fishermen grabbed it, photographed it, and waited for SAR. SAR lost it somehow when they got there. SE of Kuala Lumpur, so way outside any of the search areas.

So SAR let it get away? Even though it was far away from the search area, it could still be something because of how much time it has been drifting, unless the currents make it impossible for it to go that far. Was it a life raft that could be used in an airplane?

It seems like, though, officials don't have any ideas as to what the actual search area is because now everyone seems to be so enthralled with the idea it made a major turn.

Quoting Starlionblue (Reply 128):
Regarding sinking, the bladders could have been waterlogged.

Thank you. I did not realize that.

Starlionblue · Wed Mar 12, 2014 7:45 am

My two favored speculative scenarios right now are as follows.
- Catastrophic failure with pilots incapacitated and transponder down. Perhaps a electrical fire in the center console knocking out comms and pilots succumb to noxious gas inhalation. The plane glides intact to crash in a forested area far from habitation. This sequence of events is of course ludicrously unlikely but not completely outside the realm of possibility.
- Hijacking or other such shenanigans.

Quoting Enobar (Reply 129):
Thanks for the clarification. Interestingly enough you say that it would be unlikely that all those methods would fail, yet we seem to be looking at that very situation (barring human intervention in turning it off..). I bring this up not to argue, but because I'm wondering if there is now the possibility that the electrical failures were so severe that the black boxes could have been knocked out too? Is that possible - i seem to recall that in some previous accidents at least the CVR has been disabled (though my memory fails to bring a specific one to mind).

The recorders are at the other end of the plane but of course that's not where they get their electricity.

As I see it, if all that comms stuff actually suffers a failure, you're dead because it would imply a ridiculous amount of other things have failed also.

Quoting Enobar (Reply 129):
Also, do modern data/voice recorders operate for longer than they used to? didn't they once only record 30 minutes or so on a loop?

30 minutes is the mandatory legal minimum if memory serves. Some modern recorders go longer. However remember that the 777 is a 20 year old model so the FDR may well be at least as as old in design.

Then again, more than 30 minutes is not really needed.

Quoting laxboeingman (Reply 131):

Quoting laxboeingman (Reply 126):
Didn't we have some things recovered from AF447 by this point.

I am asking again.

Yes. Several things in fact. They found stuff on day two.

[Edited 2014-03-12 00:47:50]

[Edited 2014-03-12 00:54:44]

slinky09 · Wed Mar 12, 2014 7:47 am

Quoting Finn350 (Reply 65):
Apparently, MH did not have the same level of ACARS monitoring as AF. However, I assume that ACARS should have sent messages of system malfunctions. As there are no such messages, ACARS either itself or its communciations failed or it was turned off.

Has any information been released about the frequency of MH's ACARS communications or triggers for them? With AF447 they were very frequent, sometimes faults being report several times a minute. Even if MH's 'account' transmitted every 30 minutes then there should be a record of location after turning back, if indeed they did and if not then the original search area is where to look. If ACARS was switched off then that's another puzzle.

panampaul · Wed Mar 12, 2014 7:48 am

Malaysian officials are contradicting one another. Now the Air Force is saying that the plane did not head over the Strait.

Malaysian Air Force: Plane Did Not Detour Over Strait

To wit:

Quote:
A Malaysian air force official added to the confusion surrounding the search for the missing Malaysian Airlines flight when he categorically rejected reports that the Malaysian military had tracked the plane by radar over the Strait of Malacca, one of the world’s busiest maritime shipping channels....

.

Starlionblue · Wed Mar 12, 2014 7:50 am

Quoting slinky09 (Reply 133):
Has any information been released about the frequency of MH's ACARS communications or triggers for them? With AF447 they were very frequent, sometimes faults being report several times a minute. Even if MH's 'account' transmitted every 30 minutes then there should be a record of location after turning back, if indeed they did and if not then the original search area is where to look. If ACARS was switched off then that's another puzzle.

Only if the ACARS reports included position, and I don't think that is a given.

You're also assuming that the plane flew for a bit after turning.

And what if there were no faults to report? Transponder CB pulled. Keep flying. Nothing wrong mechanically so as I understand it ACARS would says nothing.

[Edited 2014-03-12 00:56:39]

tim73 · Wed Mar 12, 2014 7:51 am

Strait of Malacca, about 70000 ships yearly, almost 200 per day. Half of world's shipping traffic. Most of those ship will sail further into South China Sea. So about 1000 bigger ships have been sailing there in sunny weather during last five days. Plus thousands of smaller fish and other boats all around. 22-25 planes and 40+ ships from nine different nations searching.

Still, not even one possible debris sighting!

gr325 · Wed Mar 12, 2014 7:57 am

My colleague found this in Tomnod

http://www.tomnod.com/nod/challenge/malaysiaairsar2014/map/221

Any thoughts?

johnsonseattle · Wed Mar 12, 2014 7:57 am

I spotted something that looks to me like a fuel or oil slick in the Tomnod imagery. Centered around map 11206, but extending a few maps to the left and right.

There are oil rigs elsewhere in this map sector, but not immediately adjacent to the tagged area.

Does anyone know if tagging these actually calls attention to them somehow?

http://www.tomnod.com/nod/challenge/malaysiaairsar2014/map/11206

laxboeingman · Wed Mar 12, 2014 7:57 am

Thank you to everyone who responded to my AF447 question. I can say that this is now 100% different than AF447 rather than 99%.

zeke · Wed Mar 12, 2014 7:59 am

Quoting GSP psgr (Reply 95):
New Straits Times reports life raft found in waters near Port Dickson, just south of KL. There's even a photo of it.

http://www.nst.com.my/latest/font-co...en-find-life-raft-near-pd-1.509222

Most airliners that I am aware of, including the 777 have silver slide rafts, have a look at the SFO accident photos.

milestones787 · Wed Mar 12, 2014 8:00 am

OK I have a very newbie kinda question that I might as well ask: With the importance that the transponder carries, why is it even able to be turned off? Is there any practical reason when it is needed to be turned off?

barney captain · Wed Mar 12, 2014 8:05 am

Quoting milestones787 (Reply 143):
OK I have a very newbie kinda question that I might as well ask: With the importance that the transponder carries, why is it even able to be turned off? Is there any practical reason when it is needed to be turned off?

It is turned off at the gate to prevent saturation of the airports ground surveillance radar.

flyingturtle · Wed Mar 12, 2014 8:15 am

As it is 9 AM here and I've got to work a lot, I don't have the time now to read most of thread #14 and all the posts of #15, but I'm happy to see activity on the little wiki I opened yesterday. And I know that a.net admins may see this as an advertising, but I rather see it as a valuable resource for the our MH370 discussions.

Please paste there what we know - for example last positions, technical information concerning radars (PSR, SSR) and also debunked "facts". It really helps when answering to newbies who haven't read the past 14 threads!

airliners.net MH370 wiki

David

[Edited 2014-03-12 01:17:53]

chrcaremanav · Wed Mar 12, 2014 8:19 am

Hi! How are You? It is not easy time for Aviation Enthusiasts, that tragedy is confusing. Here is something to consider, maybe it is worth something or not, here is the article in question and take good care.

http://www.bernama.com/bernama/v7/ge/newsgeneral.php?id=1021242

aerocabin · Wed Mar 12, 2014 8:19 am

BBC World News reported that there is going to be another press conference at 4:30pm in Malaysia (so in around 12 minutes).

The Telegraph has also reported this:
"08.12 According to our correspondent in Kuala Lumpur, The press are now reassembling for government press conference about search operations. We hope it will start in 20 minutes, at 4.30pm local time."

http://www.telegraph.co.uk/news/worl...rlines-MH370-plane-crash-live.html

Let's hope there's some more information released on the search efforts.

aerocabin

sq452 · Wed Mar 12, 2014 8:21 am

The problem with the contradicting information is there doesn't appear to be any "unified" press spokesperson; you have the transport minister, the director general, the CEO of MAS, and so on and so forth all seemingly doing their own thing and making their own statements, then the military comes in at the 11th hour to contradict something that has already been said hours earlier. It's nuts. Crisis management training anyone? I know in a crisis there is usually a very fluid situation and information is evolving and changing constantly but if you have someone with proper crisis management training then they'll be able to filter everything and get information out to the public in a unified and succinct way so that it doesn't look like amateur hour at the podium.

On another note, anyone else having trouble getting Tomnod loading on their comp? It won't load for the life of me and I am ready to look at some maps and help with the search. I am honestly at a loss for words as to what happened with this aircraft, so puzzling.

flood · Wed Mar 12, 2014 8:25 am

Quoting PhilV (Reply 109):
Something from Vung Tau region again.

http://twitpic.com/dy1qmm

Thought it was ruled out.. Maybe fake?

The report itself looks legitimate, the question is what he actually saw. He estimated the object to be 50-70km... that's quite a distance.

His rig location, marked to the right in yellow with the object he apparently observed in red:

Quoting gr325 (Reply 139):
My colleague found this in Tomnod

Access to Tomnod appears to be iffy for many at the moment. It would help if people could post screenshots here (rather than direct links to their maps) so others can see the image in question. This would also help take some of the load off their already overloaded servers.

Quoting milestones787 (Reply 143):
why is it even able to be turned off? Is there any practical reason when it is needed to be turned off?

It's been addressed in more detail further up.

Quoting SQ452 (Reply 149):
On another note, anyone else having trouble getting Tomnod loading on their comp?

Yep.

flyingturtle · Wed Mar 12, 2014 8:31 am

Quoting flood (Reply 150):
Access to Tomnod appears to be iffy for many at the moment. It would help if people could post screenshots here (rather than direct links to their maps) so others can see the image in question. This would also help take some of the load off their already overloaded servers.

http://ireport.cnn.com/docs/DOC-1103537

There's also a page about this in the MH370 wiki, see http://mh370.wikia.com/wiki/Discussi...ject_%28ship%3F%29_found_on_Tomnod

David

Coal · Wed Mar 12, 2014 8:35 am

Is the press conference happening? It's 4:30pm here in SE Asia but CNN is not airing anything.

Cheers
Coal

Starlionblue · Wed Mar 12, 2014 8:36 am

Quoting milestones787 (Reply 143):

OK I have a very newbie kinda question that I might as well ask: With the importance that the transponder carries, why is it even able to be turned off? Is there any practical reason when it is needed to be turned off?

This has been covered. Transponders need to have an off switch and a circuit breaker for a few reasons.
1. To prevent saturation at busy airports and in busy airspace.
2. During maintenance when the plane is powered up on the ground without the intent of moving it.
3. Most importantly, in order to be able to isolate the electrical circuit if it malfunctions. All circuits on the plane can be cut with a circuit breaker in the cockpit because if you have, say, electrical arcing, you want to shut the darned thing off before anything catches fire.

Circuit breakers are an important safety feature on any circuit. If the transponder system is changed so it cannot be turned off, you are introducing a host of new risks which will endanger far more flights than the one every decade or two that can't be found immediately. Consider also that if this plane has crashed and everyone is dead, an always on transponder wouldn't have saved any lives.

[Edited 2014-03-12 01:38:15]

YokoTsuno · Wed Mar 12, 2014 8:40 am

Quoting PlaneInsomniac (Reply 145):
Frankly, tragic as it may be, it is time for somebody to step up and officially declare the plane lost and everybody dead, for which there is a 99.9% probability. The French did it within the day, and I believe it was the best they could have done for the relatives.

In the unthinkable event that the airplane will never be found, which jurisdiction/authority actually declares the passengers officially deceased?

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