How tough are EPIRB's

Submitted: Tuesday, Mar 25, 2014 at 12:06
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The last couple of weeks news has been consumed with the missing aircraft. Just wondering how tough an EPIRB is and would one survive a serious crash either in a car or plane crash. For me I find it amazing that an aircraft doesn't have some signalling device which automatically turns on in the case of an emergency.

In the USA the OnSat system for cars automatically turns on if the airbags are deployed and an distress signal is sent to OnSat, if the driver does not reply the authorities are notified of a crash.

What would have happened if a passenger in the plane activated an EPIRB could it have survived an ocean impact an floated giving a precise location of the crash.

Just wondering.
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Reply By: Boggs - Tuesday, Mar 25, 2014 at 12:15

Tuesday, Mar 25, 2014 at 12:15
I think if a personal EPIRB didn't survive neither would the passenger! I'm not even sure if you are allowed to carry a personal EPIRB in hand baggage. The only personal EPIRBs that self activate are the marine typre on contact with water.
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Follow Up By: garrycol - Tuesday, Mar 25, 2014 at 13:11

Tuesday, Mar 25, 2014 at 13:11
An aircraft as well - most likely detroyed in the crash.
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Follow Up By: Nomadic Navara - Thursday, Mar 27, 2014 at 19:58

Thursday, Mar 27, 2014 at 19:58
Personal Distress radio-beacons are not EPIRBs. They are PLBs (Personal Locator Beacon.) EPIRBs float, PLBs do not. A personal beacon would go down with the passenger.

Aviation ELTs (Emergency Locator Transmitters) are the class of beacons used in aircraft. They are designed to be as tough as the black boxes. They will survive the crash.

There is a problem with PLBs and ELTs however. Their signals will not penetrate a few thousand meters of salt water. The authorities are reliant on finding some reckage to locate the plane and then to track the signal emitted from the black box for sonar detection
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Reply By: Emerging I.T. - Tuesday, Mar 25, 2014 at 13:08

Tuesday, Mar 25, 2014 at 13:08
It's a very good point Lyn, I hope the MH370 legacy is a change in some very old fashion aviation technology. The planes should be trackable no matter although sadly it seems this plane didn't want to be.
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Follow Up By: Lyn W3 - Tuesday, Mar 25, 2014 at 15:47

Tuesday, Mar 25, 2014 at 15:47
I simply had no idea that commercial aircraft can't be tracked if their transponder (or whatever) is turned off.

just wondering if the whole story will ever be known.
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Reply By: Robin Miller - Tuesday, Mar 25, 2014 at 16:34

Tuesday, Mar 25, 2014 at 16:34
Time will show that MH370 was in effect tracked Lyn.

As for Epirb's , the specs are tough but I have seen the implementation of some of them and the electronics , well lets say its one of those unstated reasons why I like to have control in my hands and choose HF as the primary notification device.

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Follow Up By: The Landy - Wednesday, Mar 26, 2014 at 08:23

Wednesday, Mar 26, 2014 at 08:23
Robin

I’m with you on this one, an aircraft flying into the Southern Ocean region via the Indian Ocean, seemingly going no-where, would have been of interest to defence interests in the least. Maybe I’m a bit of a cynic, but even if they did track it, whoever they are, they are unlikely to divulge as it gives up defence monitoring capabilities. The Jindalee over the horizon radar has far reaching capabilities for instance…

On EPIRBs, we were required to have one located in our aircraft, and this is a requirement for all aircraft on the Australian register that will activate on impact – at least they get to find the remains of aircraft and occupants. They are very robust as they are designed for that specific purpose.

Cheers
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Follow Up By: Member - PJR (NSW) - Thursday, Mar 27, 2014 at 10:17

Thursday, Mar 27, 2014 at 10:17
Landy You are touching on a very big problem with our huge coastline. Land base radar only goes to the horizon and the OTHR (Over The Horizon Radar) system I believe is looking northward. I don't even know if is even working.

So unless we have a plane or ship patrolling out that way, then we wouldn't have know they were there. And then we get to the Defence budget! Let's not go there hey.

Yes it would be nice but we can't afford it. I can't afford a guard parked out the front. I rely on a phone call to the security center if the house is breached or on fire.

Phil
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Follow Up By: Member - PJR (NSW) - Thursday, Mar 27, 2014 at 10:34

Thursday, Mar 27, 2014 at 10:34
Robin

Wouldn't EPIRBS be a bit like the plane's Black Box growth and development. Originally not much more than voice and a few controls. These days I saw that they get almost a full breakdown of all sensors, voice and a whole bunch of the computers flight log etc, and of course all voice.

I think that the EPIRB is also a growing technology and as the Americans have done will also extend into cars especially as the later models are so electronically "smart" and physical size of the components inside an EPIRB shrink. Isn't it true that the technology that we wonder at today has been known for decades but mainly for financial and mechanical or physical reasons has not been implemented until today.

Now just some food for thought and not necessarily OT:
They will "grow". I also wonder where it will stop though. Will we all have one on our wrist watch or embedded into the lose skin at the back of the neck. Will the doctor be able to connect to my pacemaker and give me a medical.

How long will we be able to maintain control.

Now there is a little food for thought.

Phil
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Follow Up By: Member - Frank P (NSW) - Thursday, Mar 27, 2014 at 11:16

Thursday, Mar 27, 2014 at 11:16
Hi Phil

" Land base radar only goes to the horizon"

That would be correct if it is trying to detect something on the surface.

For airborne targets there are a number of things that affect range. If the radar is powerful enough, the two most important are the elevation of the radar and the altitude of the target.

Our civilian radars used for air traffic control have a typical range of about 160 nautical miles (about 320km) for aircraft at civilian jet altitudes (29,000 to 40,000 feet).

Even so, MH370 would not have been detected by Australian ATC radar - it was never within the range of any of them.

There are other tracking devices used by ATC when an aircraft is out of radar range, but they had been disabled on that flight. (Reason yet to be determined)

So authorities are now relying on position data supplied by the military technologies (which are vastly superior to civilian ATC technologies) of various nations. There are political inferences with that - revealing accurate location information may also reveal the intelligence-gathering capabilities of the country supplying the information, something most regimes are unwilling to do.

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Follow Up By: The Landy - Thursday, Mar 27, 2014 at 11:44

Thursday, Mar 27, 2014 at 11:44
Being a mere mortal I’ll preface this by saying “what would I know”.

But here is the thing. The Indian Ocean is crawling with military assets; in the air, on the surface, and under the water. These days it is all about detection, and if you look at the defence capabilities of some nations that we know of, it is astounding.

Without wanting to get into a hypothetical discussion about who might have known what, I find it difficult to conclude that it wasn’t observed and tracked by military hardware at some stage given its flight path, seemingly to no-where.

And of course, we many never know, as to reveal that a country’s defence forces observed it raises to issues, firstly they didn’t step forward earlier, and secondly, usually no country wants to highlight its capability.

Perhaps I’m a bit of a conspiracy theorist, but I suspect the real truth will never emerge…
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Follow Up By: Member - Frank P (NSW) - Thursday, Mar 27, 2014 at 12:20

Thursday, Mar 27, 2014 at 12:20
I am leaning toward that too, Landy.
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Follow Up By: Member - PJR (NSW) - Thursday, Mar 27, 2014 at 13:04

Thursday, Mar 27, 2014 at 13:04
I didn't worry about the accuracy of my post. 160 kilometers in thousands is not worth the hassle of then telling the uninitiated why it would go beyond the "horizon".

Seems like there finding more and more bits by satellite. Nothing picked up yet to confirm it.

Seems more likely that the Inmarsat boffins tracing the phone "keep alive" ping were maybe on the correct track. I don't think that this Inmarsat work was done by defence technologies. But the photos were for sure. Or maybe by oceanographic and weather satellites that do not necessarily have a defence roll.

However I really don't care. But it would be nice to find the plane and give the relatives closure. That does matter.

Phil
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Follow Up By: The Bantam - Thursday, Mar 27, 2014 at 23:55

Thursday, Mar 27, 2014 at 23:55
I think one thing that people may not fully grasp is the distance the suspected crash site is away from anything.

2000 Km is a very long way...and its not 2000Km away from London or New York its 2000Km away from Perth...as far as the rest of the world is concerned that is 2000Km away from nowhere.

There are not many wireless electronic systems that are reliable or at all effective over that distance without a satelite.

The middle of the indian ocean might as well be a black hole......its so far from any where it would be of very little military interest to any body...as for crawing..with anything but fish.....I don't think so.

The area is just vast.

You could put all the ships of all the Navies in the world out there and have enough room that they could all be out of visual range of any other ship.

Vast serioulsy vast.

cheers
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Reply By: Dennis Ellery - Tuesday, Mar 25, 2014 at 16:55

Tuesday, Mar 25, 2014 at 16:55
GPS devices similar to a SPOT, that fires off a signal to the satellite every few minutes, are in common use by recreational users and by truck companies to show vehicle location. If they had one of these in an external compartment of a plane, activating at take off by movement or air pressure – would give the last coordinates of an explosion or crash.
The technology is not the problem – it’s whether people see a need for another system sending data between the plane and its base.
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Follow Up By: Member - PJR (NSW) - Thursday, Mar 27, 2014 at 10:10

Thursday, Mar 27, 2014 at 10:10
Dennis Isn't that how they now believe they know what direction the plane took. I though that I heard something released by Inmarsat that they finally worked out which direction it took.

It appears that the on-board mobile phone system had a "keep alive" network connection to it's satellite network, and it allowed the boffins at Inmarsat to eventually get an idea where the plane could have gone.

I wonder if they could trace us. We use Inmarsat. Hmmm. Can't bloody well get away can we!!! Big Brother is watching.

Phil
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Reply By: Bob Y. - Qld - Tuesday, Mar 25, 2014 at 17:00

Tuesday, Mar 25, 2014 at 17:00
Lyn,

Don't know how robust these little items are, but would imagine the catastrophic forces involved in a crash might be too much to remain serviceable. Have seen them in helicopters, and they are a bit larger than the "personal" ones.

Re tracking of aircraft, one bloke rang one of the talk-back shows and wondered why they don't use a similar GPS set-up that are used in heavy transport in Australia. From my experience, these can tell the owner where the truck is, what speed it's doing, what direction, and when it's stationary, whether the engine is stopped or idling. Also believe some companies can control the power rating of the truck, say once it has crossed an area requiring full power, the power can be reduced, to conserve fuel. Most of the fridge vans one sees around the country are GPS controlled, and all the driver has to do is keep the fuel up to them, and maybe check the temperature, everytime he stops.

The mob I work for, also have very good cameras in the trucks, for "safety reasons", and I am sure, although they say not, that they could remotely turn on the camera, maybe to check whether you are picking your nose, or a similar activity :-)))

As for MH370. we'll maybe never know why,

Bob.

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Follow Up By: Lyn W3 - Tuesday, Mar 25, 2014 at 17:22

Tuesday, Mar 25, 2014 at 17:22
Bob,

We have GPS Auto Steering Control on two of our Row Crop tractors which records all movements including speed, direction etc. Even does a loud warning every 15 min. "Driver Alive Alert" where you have to tap the screen or the tractor will stop.
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Reply By: Member - Scott M (NSW) - Tuesday, Mar 25, 2014 at 17:29

Tuesday, Mar 25, 2014 at 17:29
I suspect the larger issue isn't whether they had these things on-board (and I have some familiarity with ACARS), is whether they should be able to be turned off or not.

Difficulty is - for safety the crew need to be able to pull the power the PM Bus's if needs be in the case of fire or failure - if the safety tracker is connected to the main power supply ..........................

Maybe there should be some device that is independent of the main supply an able to run for a theoretical maximum flight time if disconnected?
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Reply By: The Bantam - Tuesday, Mar 25, 2014 at 22:58

Tuesday, Mar 25, 2014 at 22:58
A couple of things to consider.

Even the standard marine EPERBs are fairly tough....even if the aircraft carry a similar hardened unit...it has to survive an impact into water that may be a couple of hundred miles an hour...and then float free.

EPERBs only operate if they are triggered.

Most of the distress systems on planes depend on being manually activated.....an asumption that they want to be rescued.

As for tracking.....I gather there are tracking systems, but the task is whole lot more complex in international air space, traveing at a couple of hundred miles an hour, than it is on the ground in a single country at less than 70 miles an hour.
The ground bassed systems can be suplimented by ground bassed transponders and communicate via the normal celular phone system ( when there is coverage)

The biggest problem is what the transponder will transmit too and how much power is required to do this.....the plane in question is suspected to have gone down what..2000Km away from the nearest contenent...that is Australia..that is a long way from anywhere.

An EPERB transmits a couple of watts and only continues for ...from memory 36 hours.....it is recieved by satilites specific to the purpose .....in some places it may be an hour or more between overflights.....and that system is only tracking emergencies......its not tracking several thousand vehicles world wide in continuous use.

IF this plane went down where it is susected...someone knew exactly what they where doing...and have made this plane as hard to track, locate and salvage as it possibly could be.

Cheers
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Follow Up By: Stevesub1 - Wednesday, Mar 26, 2014 at 08:22

Wednesday, Mar 26, 2014 at 08:22
http://www.spidertracks.com/

Designed for tracking aircraft, cheap as. Designed after it took 2 weeks to find a smashed helicopter. The aircraft industry is still using technology of the 60's in the main for comm's and location, not making use of the satellite technology of today.

http://english.martinvarsavsky.net/general/aviation-is-stuck-in-the-60s-a-reflection-on-mh-370.html
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Follow Up By: The Landy - Wednesday, Mar 26, 2014 at 08:26

Wednesday, Mar 26, 2014 at 08:26
All aircraft on the Australian register are required to have EPIRBs fitted that operate on an inertia basis, that is on impact...
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Follow Up By: The Bantam - Wednesday, Mar 26, 2014 at 20:49

Wednesday, Mar 26, 2014 at 20:49
But when a large plane hits the water at a couple of hundred miles an hour.
Not much is going to be in one piece.

cheers
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Follow Up By: The Landy - Wednesday, Mar 26, 2014 at 21:17

Wednesday, Mar 26, 2014 at 21:17
Usually only a blackbox and an epirb!
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Follow Up By: Robin Miller - Thursday, Mar 27, 2014 at 08:22

Thursday, Mar 27, 2014 at 08:22
My experience with those sorts of devices doesn't actually relate to the physical characteristics but rather the internal electronic design.

Still , when I was once reviewing the design of a saftey device at petrol stations , I always remember the comment about wether to implement a better sort of oscillator and comment went - well its not as though its likely to ever actually be used !
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Follow Up By: Member - Rod N (QLD) - Thursday, Mar 27, 2014 at 10:57

Thursday, Mar 27, 2014 at 10:57
As The Landy said, aircraft Crash Position Indicators (CPI) are operated by an inertia or G switch. They also have provision to be switched on by a switch on the CPI or a switch in the cockpit. They transmit a code which relates to the aircraft tail number and position.
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Follow Up By: Member - Frank P (NSW) - Thursday, Mar 27, 2014 at 12:00

Thursday, Mar 27, 2014 at 12:00
"The biggest problem is what the transponder will transmit too and how much power is required to do this.....the plane in question is suspected to have gone down what..2000Km away from the nearest contenent...that is Australia..that is a long way from anywhere."

There has been considerable mention here and elsewhere of the aircraft's transponder. It is not really relevant because it relies on a query from ATC radar (max range about 320km - see Followup 811969 further up the page) before it replies with limited information (which does NOT include position) to ATC.

The really useful piece of kit is ACARS. This broadcasts, amongst a heap of other things, the aircraft's position, via satellite to whoever wants to receive it. Range from land-based stations is not an issue. For a demonstration, install an app called Flight Radar 24 on your iOS or Android device. (Get it from the Appstore or Google's Playstore. It is free.) It will appear that your phone or tablet has turned into a world-wide radar system. The info required to make this happen comes from ACARS.

The missing aircraft had this equipment and was using it, but along with other communications equipment, it was switched off or deactivated early in the flight for reasons as yet unknown. Had it not been deactivated we would know precisely where the aircraft went down.

I would not be surprised if one of the results of this accident is the compulsory use by commercial aircraft of a tracking device like ACARS that is somehow powered separately from everything else and cannot be switched off while the aircraft is in flight.

This raises issues of the sovereignty of nation states. There is an organisation called the International Civil Aviation Organisation. Member states (the majority of nations) of ICAO bind themselves to its recommendations and directives. Some other states like to go their own way.

Cheers

Frank (retired ATC)
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Reply By: Nomadic Navara - Friday, Mar 28, 2014 at 00:34

Friday, Mar 28, 2014 at 00:34
There is a heap of light reading links on this page.
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